,rii,i.i, iiTTT ii,i,i,i,i,i,i i,i,i.i,i,i,i,i,i,i,i,iriTi |ii , 1 Storrs A[(riciiltiiral Collep j Vo/..*^0.^.0 I ' C!j- .Vc'.-SST) I PKIiSKNTEn KY i.i.i.i.i.i.i.i j . i . i 1, 1 , 1 .1.1.1 1 1 ] i Timm^ Please handle this volume with care. TheUmvenityofCoimechcut Libraries, Storrs DEPARTMENT OF THE INTERIOR MONOGRAPHS United States Geological Survey VOLUME XXXYIII WASHINGTOlf GOVERNMENT PRINTING OFFICE 1899 Digitized by the Internet Archive in 2009 with funding from Boston Library Consortium IVIember Libraries http://www.archive.org/details/illinoisglaciallOOIeve UNITED STATES GEOLOGICAL SURVEY CHARLES D. WALCOTT, DIRECTOR THE ILLINOIS GLACIAL LOBE BY FR^NK LEVERETT WASHINGTON GOVERNMENT PRINTING OFFICE 1899 ^&^l CONTENTS. Letter of transmittal xv Abstract of voLUiMii xaii Chapter I. — Introduction 1 Chapter II.— Physical features 7 Chapter III. — Outline of time rel.a^tioxs or glacial succession 19 Chapter IV. — The Illinoi an drift sheet and its relations 24 General statement 24 Relation to outlying and underlying drift 24 Relation to the lowan drift sheet 24 Culmination of the Illinois lobe at the Illinoiau stage 25 General aspects of the Illinoiau drift sheet 25 Extont of its exposures 25 Topographic expression - - 26 Thickness of the drift 27 Structure of the drift - -- 27 Gumbo (?) 28 Sections of the Illinoiau drift 33 The drift border 1 -- 34 Distribution - 34 Topographic expression 38 .Structure of the drift border 40 Character of the out wash 70 The i-idged dri ft of the Kaskaskia Basin 71 Buffalo- Hart moraine 74 Eskers or gravelly rjdges of northwestern Illinois 76 Leaf River or Adeline esker - 76 Hazelhurst esker 78 Garden Plain esker 79 Pecatonica esker system - 80 CedarviDe belt 81 Orangeville belt.. 81 General observations - 82 Transported rook ledges - 82 Glacial stria; - 84 Effect of the Illiuoian ice invasion on the outer-border drainage 89 Temporary displacement of the Missis8ii)pi River 89 Changes of drainage in southwestern Indiana , 97 Plei-stocene deposits beneath the Illiuoian till sheet 105 Kansan till 105 Pre-Illiuoian till and associated deposits j 107 Silveria ( ?) formation and other silt deposits Ill Chapter V.— The Yarmouth soil and weathered zone 119 Weathering of the buried Kansan drift - 119 Buried soil, peat, etc 120 Erosion of the Kansan drift sjheet 121 Organic remains 123 Y VI CONTENTS. Page. Chaptki! VI. — The Sangamon .soil and weathered zone 125 CriAPTEii VII. — The Iowan driet sheet and associated deposits 131 The Iowan sheet of the Illinois lobe 131 Distribution or extent - 131 Topographic expression - 134 Thickness of tlie drift 136 Structure of the drift - 137 StriiB 140 Probable extent of Iowan drift sheet beneath the Wisconsin 141 Probable extent of Iowa portion of Iowan drift 144 Relation of the Illinois and Iowa ice lobes 151 The Iowan loess - 153 Distribution - 153 Variations in thickness 155 Structure - 156 Fossils - 165 Mode of deposition - 176 Chapter VIII. — The Peorian soil and weathered zone (Toronto ior.mation?) 185 General statement 185 Soil and peat between the Iowan and AViscons-n drift sheets 185 Leached loess beneath the Wisconsin drift 187 Iowan outline compared with succeeding and preceding glaciations 188 Change in attitude of the land 188 Length of the Peorian stage - - 188 The Toronto formation 189 Chapter IX. — The early Wisconsin drift sheets 191 General statement 191 Section I. Shelbyville morainic system 192 Extent of the Shelbyville sheet 192 Shelbyville moraine 192 Distribution 193 Relief 194 Range in altitude 194 Surface contours _. - 195 Structure and thickness of drift - 197 Character of out wash 208 Inner-border tr.act 213 Topography 213 Thickness of drift 213 Structure of d rift 213 Cerro Gordo moraine 218 Distribution 218 Topographic expression 218 Structure of the drift 219 Character of out wash 221 Inner-border tract 222 Section II. Champaign nmrainic system 223 Distribution 223 Relief 225 Range in altitude 226 Surface contours 227 Thickness and structure of drift 231 Character of outwash 237 Associated till plains 239 Section III. Bloomington morainic system 240 Distribution 241 Relief 244 CONTENTS. yjj Chapter IX.— The eai!ly Wisconsin drift sheicts— Coutinued. Section III. Blooiuington morainic system— Continued. ^^^' Ran,!>e in altitude ,._ --. .._._.. , __ — .... -.-...__...._.. 24:0 Snrf'ace contours _._ '' . . .. — , , — .. __ — _ ^ ■i45 Between western Kane County and the head of Bureau Creek 246 In Bureau Creek drainage basin 1^.^ In Bureau, Marshall, and Peoria counties "" 25O , Between the Illinois and Mackinaw rivers 9-, Between the Mackinaw River and Ford County reentrant 055 The reentrant in Ford County 9-T Eastward from the Ford County reentrant to western Indiana 255 The ijortion covered hy the late Wisconsin drift 257 The weak moraine in eastern Iroquois County, Illinois 258 Cropsey Ridge f,_„ Chats worth-Cayuga Ridge ~)sq Farm Ridge or Grand Ridge oro Thickness of drift 9„f, Structure of drift ZJl " .iDO Character or outwash „..„ ^ ^ " 270 Intermorainic tracts .„„ Distribution or extent i .jo„ General features ' 9„„ Thickness of drift ^o^ Structure of drift : . . 900 Kaneville esker and delta 901 Little Rock esker, or " Devils Backbone " oita Covel Ridge " ^sg Onarga Ridge „on ^ ° 289 Section IV. The composite morainic belt of northern Illinois 09O Marengo Ridge f,q„ Distribution ^\^ Relief .jQ^ Surface contours 9q^ Thickness of drift 90, Structure of drift 9qo Character of outwash . . r,q. Inner-border phenofiiena 9q- Correlations .,„_ Portion of the composite belt west of Fox River om General features 9q_ Structure of drift onn Correlations 0^9 Portion of the composite belt cast of Fox River 304 Distribution and connections nn< General features oj,^ Thickness of drift ." ong Structure of drift onp Section V. The Marseilles moraine oqj Distribution 007 Range in altitude ong Relief _ o/.q Surface contours oqq Thickness of drift 011 Structure of drift 3j2 Character of outwash gj^o Inner-border til.1 plain qjg Vlir CONTENTS. Page. Chapteu X.— Thk late Wisconsin nRii-r sheets 317 Basis for separat ion from the early Wisconsin 317 Outline of the late Wisconsin liorder .-. 318 Section I. The Minooka till ridge 319 Ilistribution 319 Probable line of continuation -- - 319 Relief - 320 Thickness of dri It , 320 Structnre of drift - - 321 Character of the outwash 321 Inner-border till plain 324 Section II. Bowlder belts 325 Section III. Lake Kankakee 328 Extent of the sand - 329 Range in altitude of the border of the sand - 331 Surface contours - - 33- Thickness of the sand - 333 A'ariatious in coarseness - - 333 Interpretations - 334 Section IV. The Valparaiso morainic system - 339 Distribution 339 Border between the Lake Michigan and Saginaw Bay lobes 340 Range in altitude - 34.3 Surface contours - 345 Detailed description of the Michigan portion 34!^ Thickness of the drift -- 353 Structure of the drift - - 356 Character of the outwash 375 Section V. The lake-border morainic system - 380 Till ridges of Lake and Cook counties, Illinois 380 The outer or west ridge 380 The middle ridge - 381 The east riilge 381 Probable continuations 382 Relief 384 Thickness of drift : 384 Structure of drift 38.i Till ridges on the southeast border of Lake Michigan 386 Tho outer ridge - --■ 386 Covert Ridge 388 Zeeland Ridge 390 Relief 391 Range in altitude 391 Thickness of drift 39- Structurc of drift 393 Character of the outwash ; 403 Associated till plains 404 Altitude and slopes 4"* Thickness of drift ■106 Structure of drift -107 Section VI. Stria' within limits of Shelbyville moraine 412 Chapter XI. — The Chicago Outlet and iieaches op Lake Ciucaoo 418 Previous writers 418 The Chicago Outlet *20 The glacial T^ake Chicago 427 Upper, or Glcu wood, beach 428 CONTENTS. IX Chapter XI. — The Chicago Outlet and beaches of Lake Chicago— Continued. Pao-e. The glacial Lake Chicago — Continuefl. Interval of emergence _ 440 Second, or Calumet, beach __ 443 Possible second emergence 44g Third, or Tolleston, beach 447 The preseut beach of Lake Michigan _ 453 CHArTEi; XII. — Influence of the drift on drainage system.s and drainage conditions.. 460 The Mississippi Valley 461 Accession from the north (?) 461 Minor deflection at Fultou, Illinois 462 Deflection past the Leclaire, or upper, rapids 463 Reestablished stream between upper and lower rapids _ . _ 467 Deflection at the lower rapids ' 469 Reestablished stream below the lower rapids 473 Deflections south of glacial lioundary 474 Rock floor and present stream compared 474 Minor tributaries of the Mississipppi _. 477 Apple River 477 Plum River 478 Edwards River 478 Henderson River _ 479 Flint River 479 Lost Creek 480 Bear Creek 480 Bay Creek 480 Big Meadow channel 481 Rock River drainage basin 483 The preglacial drainage 483 Present cour.se of Rouk River 486 Greeu River 492 Rock gorges of northwestern Illinois 493 Illinois River drainage basin. 496 The lower Illiuois 1 499 The upper Illinois 501 Des Plaines River 503 Kankakee River 505 Au Sable Creek and Nettle Creek 508 Mazon Creek, etc 508 Fox River 509 Covel Creek 510 Vermilion River _ 511 Little Vermilion River, etc 512 Bur.eau Creek 512 Kickapoo Creek 513 Farm Creek 514 Mackiuaw River 514 Quiver Creek 515 Copperas Creek 516 Spoon River 516 Sangamon River 517 Crooked Creek 520 McKee's Creek 521 Indian, Mauvaise Terre, and Big Sandy creeks 521 Apple Creek.. .' 522 Macoupin Creek 522 Otter Creek ^ 523 X CONTENTS. Chapter XII. — Inkluexce of the drift on urainage systems and conditions— Cont'd. Va.g:e. Kaskaslcia River drainage basin 523 Kaskaskia River 523 Shoal Creek 524 Silver Creek - 525 Big Muddy River drainage basin 526 Saline River drainage basin 527 Cache River - - - 528 Wabash River drainage basin - - 528 Preglacial Wabash \' alley - 529 Minor deflections of the Wabash 530 Little Wabash River -- - 530 Bon Pas River 531 Patoka River -- - 532 White River - 532 Embarras River - - 534 Busseron Creek - - 535 Big Raccoon Creek - 535 Sugar Creek 536 Vermilion River 536 Lake Michigan drainage basin - 538 Chicago River - 538 Calumet River - -- 538 Trail Creek - 539 Galien River --- 539 St. Joseph River 539 Pawpaw River - - 540 Black River -- --- 541 Kalamazoo River - 541 Chapter XIII. —Average thickness of the drift in Illinois 542 Chapter XIV. — Wells of Illinois 550 Introduction . - - _- - 550 Classification of underground waters 550 The geologic formations 552 Attitude of the strata 553 Essential conditions for artesian wells 555 Relation of the drift to ordinary wells 557 Gas wells --- 557 Tabulation of sources for city water supply 557 Detailed discussion 564 Jo Daviess County 564 Stephenson County 567 Winnebago County 569 Boone County 573 McHcnry County 575 Lake County 579 Cook County 581 Dupage County -'91 Kane County 594 Dekalb County 599 Ogle County 604 Lee County 608 Carroll County 611 Whiti^sido County 614 Rock Island County 619 Mercer County 622 Henry County 623 CONTENTS. XI Chapter XIV. — Wells of Illinois — Continued. Page. Detailed discussion — Continued. Bureau County.. - .- 626 Pntnam County - - 633 Lasalle County - — — 635 Kendall County - 643 Grundy County - - --- 645 Will County - 648 Kankakee County - - 653 Iroquois County — -- -- 654 Ford County - 662 liivingston County - 664 Marshall County - - - - - - 668 Woodford County - - 670 Stark County - 672 Peoria County 673 Knox County - - 676 Warren County - 678 Henderson County ' --- 679 Hancock County - - - 681 McDonough. Couuty - 685 Fulton County -- 686 Mason County - 688 Tazewell County 689 McLean County . - - 692 Vermilion County -- 697 Champaign County - 701 Piatt Couuty 703 Dewitt County - 704 Logan County 707 Menard County - - 709 Cass County ' - 710 Schuyler County - 711 Brown County 712 Adams County 713 Pike County . . - 718 Scott County - 721 Morgan County - - 722 Sangamon County 724 Christian County 725 Macon County — 727 Moultrie County - 729 Douglas County 731 Edgar County 732 Clark Couuty 733 Coles Couuty 734 Cumberland County 736 Shelby County 737 Montgomery County 740 Macoupin County 742 Greene County 744 Calhoun County - 745 Jersey County - - 746 Madison County 748 Bond County --- 750 Fayette County - 752 XII CONTENTS. Chapter XIV. — Wells of Illinols — Contiuueil. Page. Detailed discussion — Continued. Effingham County ''53 Jasper County ''^54 Crawford County - 755 Lawrence County 756 Richland County 756 Clay County - - 757 Marion County 758 Clinton County - 760 St. Clair County - 761 Monroe County 765 Randolph County 767 AVashingtdu County 770 Perry County - 771 Jeft'erson County - 773 AVayne County 774 Edwards and Wabash counties 775 White County 776 Hamilton County 777 Franklin County - 778 Jackson County 778 Williamson County - 780 Saline County 781 Gallatin County 783 Unglaciated counties of southern Illinois 784 CiiAPTEH XV.— Soils 788 Sources of soil material 788 ' Classes of .soil - 788 Residuary soils.. 791 Bowlder-clay soils 792 Gravelly soils 792 Sandy soils 793 Bluff-loess soils 793 Silts slowly pervious to water 794 Fine silts, nearly impervious - 795 Peaty and organic soils 796 Index - - 799 ILLUSTRATIONS, Page. Plate I Map showing the several drift sheets and the present glaciation of North America . 2 II. Map showing- base lines and principal meridians in the district covered by the Illinois glacial lobe -.; III. Topographic map of Illinois and western Indiana ^ IV Map showing areas between 100-foot contours * V. Profiles across Lake Michigan .- " VI. Glacial map of Illinois ice lobe - VII. Bowlder bed at Keokuk, Iowa J^ VIII. Glacial map of southwestern Indiana - - IX Glacial map of south-central Indiana J^ X A Sano-amon soil, near view; i?, Sangamon soil, more distant view 1-b XT. A, Exposure on Farm Creek, near Peoria; IS, exposure on railroad cutting east of Peoria " XII. Glacial map of northwestern Illinois XIII. Exposure of Wisconsin gravel -j' XIV. Glacial map of parts of Kane and Kendall counties, Illinois -JH XV. Glacialmap of southwestern Michigan 340 ■XVI. Striation of under surface of limestone '^1° XVII. Map of Lake Chicago area .'.':"" XVIII. Topographic map showing drainage features near Fulton, Illinois, and lu vicinity of the upiier rapids of the Mississippi. ; In pocket. XIX. Topographic map showing drainage features near Ottawa, Illinois 508 XX. Map of Illinois, showing distribution of wells - - - ^J^^ XXI Geoloo-ic map of Illinois and western Indiana ^o- XXIL Map showing main absorbing areas for the Potsdam and St. Peters formations -- .5.56 Xx'lII. Map showing distribution of artesian wells and deep borings 5o6 VxiV. Map showing the relation of the drift to ordinary wells 556 Fig. 1. Section of Silveria formation near Freeport, Illinois 112 2. Glaciated surface in bed of Chicago drainage canal *1d 3 Grooves exposed in bed of Chicago drainage canal 11^ 4. Sketch map of the region bordering the lower rai^ids of the Mississippi River 468 0. Section from Sonora, Illinois, toArgyle, Iowa - *69 6 Sections across Rock River Valley, in northern Illinois 7. Section from the Wisconsin River, in Grant County, Wisconsin, southward to Cap au Gres, near the mouth of the Illinois • °i^ 8. Section from Galena to Olney, Illinois - - ^^^ 9. Section from Davenport, Iowa, to Joliet, Illinois ='=' XIII LETTER OF TRANSMITTAL. University of Chicago, July 15^ 1898. Sir: I have the honor to transmit herewith the manuscript of a mono- g-raph on The lUinois Grlacial Lobe, by Mr. Frank Leverett. This is one of a series of monographs which are in course of preparation on the glacial formations of the Northern States. My instructions when entering upon the work of the Geological Survey were to prepare a monograph on the terminal moraines which stretch from Dakota to the Atlantic. Soon after the inauguration of the work, however, it became ajjparent that the mo- rainic systems were more amply and more intricately developed than had been at first apprehended, and that they, together with the associated glacial formations, were so highly diversified and so complicated that their eluci- dation could be reached only by prolonged investigation involving detailed work. It was therefore thought best to study the glaciated area by sec- tions, and to publish the results of these partial studies as they might be ready, reserving for a later date the monographic treatment of the whole. Early in the preliminary work special attention was drawn to the Illinois glacial lobe, because its morainic ridges and its till sheets were very widely deployed and because its relations were such as to make it, in some sense, a key to the whole glacial series east of the Mississippi; and hence it has been given precedence. Previous to my connection with the Geological Survey I had made sufficient reconnaissance of the area covered by this monograph to deter- mine some of its salient features, and at tlie same time to disclose many other features which only patient and detailed study could elucidate. The results of these partial studies, combined with observations made during the first year of my connection with the Survey, were embraced in a prelim- inary paper published in the Third Annual Report. The more detailed work was taken up by Prof. R. D. Sahsbury, Prof. L. C. Wooster, Mr. Frank XVI LETTER OF TRANSMITTAL. Leverett, iiiid lUAxolt' (•(injointh" in 188G. Later the whole work was coniiuitted to Mr. Leverett, with tlie gratify ing results of which this mon- ogi'aj)li is au expression. Tlie relations of Mr. Leverett and myself during- the progress of the investigation have been unusually intimate, and it has been a pleasure to contribute to the work such data and suggestions as m^- studies in this and other regions permitted. I trast that the monogi-aph will jjrove a valuable contribution to the complex problem presented by the gla- cial series of the Northern United States. Very respectfully, yours, T. C Chamberlin, Geologist in charge. Hon. Charles D. Walcott, Director United States Qeological Survey. ABSTRACT OF TOLUME. Chapter I. Introduction. — The Illinois glacial lobe formed tlie southwestern part of the great ice field that extended from the high lands east and south of Hudson Bay southwestward over the basins of the Great Lakes and the north-central States as far as the Mississippi Valley. It overlapped a previously glaciated region on the southwest, whose drift was derived from an ice field that moved southward from the central portion of the Dominion of Canada as far as the vicinity of the Missouri Eiver. This southwestern part of the eastern ice field, being mainly within the limits of the State of Illinois, has received the name Illinois Glacial Lobe. The results of earlier studies by Chamberlin, Salisbury, and others are noted, and the plan of investigation is set forth. A brief explanation of the method of num- bering townships is presented. Chapter II. Physical features. — -The variations in altitude are set forth in a topographic map and also in tables, and the marked increase in altitude of certain parts of the region because of drift accumulations is considered. The consxaicuous reliefs of the rock surface are briefly touched upon, and the preglacial valleys receive passing notice. Profiles and maps are extended across the bed of Lake Michigan as well as border districts, and the inequalities of the lake basin are briefly discussed. Chapter III. Outline of time relations or glacial succession. — A sketch of the major and minor divisions of the drift sheets and of the intervals between them is accompanied by a brief explanation of the basis for the classification adopted. Chapter IV. The Illinoian drift sheet and its relations. — The Illinoian is the most extensive drift sheet formed by the Illinois glacial lobe and receives its name because of its wide exposure in the State of Illinois. The evidence that the Illinoian drift sheet should be separated from the outlying and underlying drift and also from the lowan drift is briefly set forth. The aspects of the Illinoian drift sheet are then discussed, its topography as well as its structure being considered. In connection with this drift sheet a very adhesive clay, known as "gumbo," which caps it, is described and the questions of its relation to this drift sheet and to the overlying loess are considered. A detailed descrii^tion of the border of the Illinoian MON xxxviii 2 ^"^'ii XN'JU ABSTRACT OP VOLUME. drift sheet is then given, wbicli is followed by a description of the moraines and other drift aggregations back from the border. Remarkable instances of the transportation of rock ledges are noted. The strife pertaining to this invasion are discussed iu some detail. The effect of this ice invasion and its drift deposits upon the outer-border drainage is touched upon, but the detailed discussion of the influence of the drift upon drainage is deferred to a later chapter. The chapter closes with a discussion of the deposits which underlie the Illinoian drift sheet. Chapter V. The Yarmouth soil and weathered zone. — A well-defined soil and weathered zone which appear between the Kansan and Illiuoian drift sheets in the overlap of the latter upon the former are described, and sections are presented which show clearly the relations to these drift sheets. The amount of erosion effected during the interglacial stage is also considered. The name Yarmouth is taken from a village iu southeastern Iowa, where the interglacial features were first recognized by the writer. Chapter VI. The Sangamon soil and weathered zone. — Another well- defined soil iind accompanying weathered zone which appear between the Illinoian drift and the overlying loess are described. The name Sangamon is applied because these features are exceptionally well developed in the Sangamoa River Basin in Illi- nois and were there first noted by Worthen in the early reports of the Illinois geological survey. Chapter VII. The Iowan drift sheet and associated deposits. — The name Iowan was applied by Chamberlin to a sheet which is well displayed iu eastern Iowa and which had beeu brought to notice by McGee. The chapter opens with the discussion of a drift sheet of a similar age which was formed by the Illinois lobe, its extent, topographic expression, and structure being considered. The relation of this ice lobe to the Iowa ice lobe, and the relation of each to the great loess deposit of the Mississippi Basin are then considered, after which the loess is discussed. The problem of the mode of deposition of the loess forms the closing topic Chapter VIII. The Peorian soil and weathered zone (Toronto forma- tion?). — The name Toronto formation, suggested by Chamberlin, for interglacial deposits exposed in the vicinity of Toronto, Canada, may prove to be applicable to a soil and weathered zone wliich appear between the Iowan drift sheet or its associated loess and the Shelbyville or earliest Wisconsin drift sheet which overlies the Iowan. Exceptionally good exposures of a soil and weathered zone at this horizon in the vicinity of Peoria, Illinois, make it seem advisable to apply the name Peorian, while tlie relations of the Toronto formation renuiiii uncertain. Other exposures as well as those near Peoria arc discussed. A marked interglacial interval between the Iowan and Wisconsin stages of glaciation may also be inferred by a comparison of the out- line of the ice sheet at the Iowan stage of glaciation with that of the outline at the ABSTRACT OF VOLUME. xiX culmination of the Wisconsin stage. It may also be inferred by a change in the atti- tude of the laud, by -which better drainage conditions were prevalent in the Wisconsin than in the lowan stage. Chapter IX. The early Wisconsin drift sheets.— The Wisconsin drift, named by Chamberlin from the State in which it was first recognized as a distinct drift, is cbaiacterized by large morainic ridges and comparatively smooth intervening till plains which have been thrown into two groups, known as the early Wisconsin and late Wisconsin. In the first group the moraines form a rudely concentric series, which are well displayed in the northeastern part of Illinois, but are largely over- ridden by the moraines and drift sheets of the later group in districts farther east. The outer border of the second, or late, Wisconsin group is so discordant with the moraines of the first group that there seems in this feature alone sufficient reason for separation. The several morainic systems of the early Wisconsin group are taken up in suc- cession from earlier to later, the distribution, relief, range in altitude, surface contours thickness and structure of the drift, and the character of the outwash being con- sidered. In connection with each morainic system the associated till plains are discussed, attention being given to the surface features and to the structure and thickness of the drift. In northern Illinois the several morainic systems are merged into a composite belt so complex that it is difficult to trace the individual members The several moraines and their associated sheets of till do not appear to be separated by intervals so wide as are found betweeu the Illinoian and lowan or the lowan and Wisconsin drift sheets. Indeed, instances of the occurrence of a soil or a weathered zone between Wisconsin sheets are very rare. There may, however have been considerable oscillation of the ice margin. Chapter X. The late Wisconsin drift sheets.— The basis for separation from the early Wisconsin is first considered, after which the several morainic systems and their associated till plains are taken up in order as in the discussion of the early Wisconsin drift. An interpretatiou of the Kankakee sand area is attempted, though several qnestions connected with it still remain open. The chapter closes with a discussion of the striae found within the limits both of the early and of the late Wis- consin drift. Chapter XI. The Chicago Outlet and beaches of Lake Chicago.— That a body of water once extended over the low districts bordering the southern end of Lake Michigan and discharged southwestward to the Des Plaines and thence into the Illinois River has been recognized since the early days of settlement, and several papers discussing the beaches and tlie outlet have appeared. The latter has long been known as the Chicago Outlet, because it led away from the site of that city. The lake has recently been given a name in harmony with that of the outlet (Lake Chicago.) XX ABSTKACT OF VOLUME. After reviewing tbe previous reports and papers, the Cbicago Outlet is described in some detail. The several beacbes of Lake Cbicago are tbeu taken up in order from highest to lowest. Tbe chapter ends with a discussion of the present beach of Lake Michigan. Ghaptek XII. Influence of the drift on drainage systems and drain- age CONDITIONS. — It is shown that many drainage systems are entirely independent of the preglacial lines, while others are independent only in part, a considerable part of their courses being along the lines of old valleys. The development of drainage systems is shown to be much farther advanced on the lowan and Illinoian drift sheets than on the Wisconsin. This is found to be due to differences in age and not to natural advantages for discharge. The Wisconsin is, on the whole, more favored by uneven surface for the rapid development of drainage lines than the Illinoian. The several drainage systems are discussed in considerable detail. Chapter XIII. Average thickness of the drift in Illinois. — Illinois affords an especially good opportunity for the estimate of the thickness of the drift, because of the large number of well sections obtained, and because of the compara- tive smoothness of the region. The inequalities of the rock surface beneath drift plains may be estimated by the study of neighboring driftless tracts, as well as by borings and outcrops within the drift covered area. There arc thus two quite differ- ent methods by which the average thickness of the drift may be ascertained. The first method here used is that of averaging the results of borings and out- crops. These are averaged in each township in which the distance to rock is known, and the results are then combined for the average of all the explored townships. Con- sideration is then given to the distribution of the explored townships in reference to drift plains and moraines and to preglacial uplands and valleys, and necessary cor- rections are made. By this method the thickness of the drift is found to bo not less than 100 feet, and it may be 1'20 feet or even more. The second method, based upon a comparison of the Illinois drift area with the neighboring driftless tracts, gives 129.3 feet as the average thickness, or slightly more than the highest results obtained by the first method. Combining the two methods, tbe average thickness of the drift of Illinois can be i^laced at not more than 130 feet and not less than 100 feet. An attempt is made to estimate the part contributed by each ice invasion, but the data prove to be scarcely complete enough for a good estimate. It is found that the general thickness withiu the limits of the Wisconsin drift is 40 to 45 feet greater than in the portion of the State outside. Chapter XIV. The wells of Illinois. — This chapter aims to present all the reliable well records obtained within the State which throw light upon the deposits jDenetrated as well as upon the character of the water sui)plies. In addition to the wells which terminate in the drift there are included many which extend ABSTRACT OF VOLUME. XXI deeply into the underlying rock formations. This necessitates a classification of the underground waters and a description of the several rock formations penetrated, including a discussion of the attitude of the strata. The essential conditions for obtaining artesian wells are considered, and also the relation of the drift to the ordinary wells. There is a brief discussion of gas wells, confined mainly to those obtained in the drift. A tabulation of sources for city water supply is then presented, after which there appears a detailed discussion of wells, taken up by counties. Chapter XV. Soils. — The sources of soil material are first discussed. An attempt is then made to classify the soils according to their origin. Eight classes are recognized, as follows: Residuary soils, bowlder-clay soils, gravelly soils, sandy soils, bluff-loess soils, silts slowly pervious to water, fine silts nearly imj)ervious, peaty or organic soils. THE ILLINOIS GLACIAL LOBE. By Frank Levebett. CHAPTER I. INTRODUCTION. The Illinois glacial lobe includes a portion of the great ice sheet which extended from the highlands east and south of Hudson Bay, southwestward across Michigan, the Lake Michigan basin, and Illinois, to the axis of the Mississippi Valley in southwestern Illinois and southeastern Iowa (PL I). It finds its natural limits on the northwest at the border of the Driftless Area of southern Wisconsin and northwestern Illinois. On the west it overlaps a region previously glaciated, but its extent there is readily deter- mined, for it has usually a definite border in a belt of ridged drift. On the south and southeast it extends to the unglaciated tracts of southern Illinois and southern Indiana. From central Indiana northward it seems to have been merged with the eastern portion of the great ice sheet, except in shrunken stages. In the last stage here considered it extended but little beyond the borders of Lake Michigan and was then distinct fi-om lobes to the east lying in the Saginaw and Maumee basins. The present report discusses the deposits made by the lobe south from the latitude of the Illinois- Wisconsin line, in Illinois, Indiana, and Michigan. The drift deposited by this ice lobe has received considerable attention from the geologists of the several State surveys, and also from several students of geology not connected with official surveys. The early publi- cations furnish numerous sections of the drift, of which mention is made below, which throw light on its structure and thickness. They contain MON xxxvni 1 1 2 THE ILLI>fOIS GLACIAL LOBE. only occasional references to the topography of the drift surface. Appar- ently the first clear recognition of the import of morainic belts in this region was that by Prof. T. C. Chamberlin, who began his investigations in the Wisconsin Survey in 1873, and who in 1876 presented a map, before the Wisconsin Academy of Sciences, showing the distribution of the moraines of eastern Wisconsin. This was followed by one in 1878 show- ing moraines then recognized in the United States.^ It soon became apparent to Professor Chamberlin that sheets of drift of widely different age occur, the later of which are characterized by stronger morainic lines than the earlier. Prior to liie recognition of the morainic belts and of drift sheets of widely different ages the published sections of the drift presented many puzzling features. But with this recognition the sections published by the early students became of service in making interpretations. The later students are thus able to build upon the work of the earlier. The disad- vantages imder which the earlier students worked, on account of the less complete knowledge of the glacial features, can scarcely be appreciated by those who are furnished with the present facilities for study. Any en-oneous interpretations resulting from the restricted acquaintance with such featm-es merit a most charitable construction. For example, the writings of Profes- sor Worthen of the Illinois survey are full of the hypothesis of deposition of the di-ift by icebergs. The early reports of the geologists of the Indiana survey contain a similar inteipretation of the drift. In the light of present knowledge of the moraines, with their attendant valley trains of gravel and other features demonstrating the presence of land ice, the iceberg hj'iDOthesis must of course be set aside, but this study of moraines has largely taken place during the fifteen or twenty years since the reports refeiTed to were published. The present report is an outgrowth of studies entered upon by Pro- fessor Chamberlin prior to the publication of his paper in the Third Annual Report of this Survey.^ In that paper it is shown that the State of Illinois is traversed by several morainic lines lying outside the great moraine which is the theme of the paper. These lines, together with others not then ' Trans. Wisconsin Acad. Sci., Vol. IV (for 1876-77), 1878, pp. 202-234; with two maps. -Preliminary paper on tho terminal moraine of the second Olaci.al epoch, by Thomas C. Cham- li.-iliii : Third Ann. Rept. U. S. Geol. Survey (for 1881-82), 1883, pp. 291-402. U. S. GEOLOGICAL SURVEY. MONOGRAPH XXXVIII PL. 157° 137° 117° .-1 '^C E r-.T-' LoivgiLiidc 37" \Wst Crniii i^vemwich ' ^-^^. ■t(j/;'-iJ(CiayS^-~~ji-i- / B A ' r •- } ^ A) ^ — - A.VW- '7^ lOo Kansan drift Dlinoian drift i lowan di-lfl V^ ■Wisconsinandlala-drifistieets v^x Existing glaciers and ice sheets Quaternarj' lakes (Boraieville.Lahontan and Glacial LakeA^assiz) \ \\ I Glacial currents known by strias Glacial currents known by drift transportation or otherwise inferred_ 30° LoTtgilu.cle "West 20° ft:om"Waslun.fetorL JULIUS BIEN a CO. LITH N.Y, MAP OF THE GLACIATED AREA OF NORTH AMERICA. (Modified from Upham's map Plate X\t; MonographXXV) BY FRANK LE^^RE T T 1898 Scale, about .5.50 miles Lo an incli INTRODUCTION. 3 known, have been mapped in detail and a large amount of data concerning them have been collected. The detailed studies were begun in the spring of 1886, and the follow- ing statement concerning them was made bj Professor Chamberlin in his report to the Director for the fiscal year 1886-87: Messrs. L. C. Wooster, R. D. Salisbury, F. Leverett, and myself have under- taken a work that is measurably new, though a part of the general plan of work previously inaugurated. In the region about the head of Lake Michigan and between it and the Erie basin is a tract which was invaded by successive glacial movements from both these great basins, these movements being more or less inharmonious and couflicting, resulting in exceptionally complicated phenomena. There arose from this a need for detailed study and the development of more refined methods of investiga- tion than those demanded by the simpler drift tracts.' During the field season of 1886 the study was extended out for a dis- tance of 60 to 100 miles from the head of Lake Michigan in Illinois and Indiana, a division of the district being made so that each person worked a separate area. Since that season the field work has been largely carried on by Professor Salisbury and the writer, though Professor Chamberlin has constantly superintended the work and has from time to time visited the field. Professor Salisbury's work, since the first season, has been largely in southern and western Illinois, while the writer's has been mainly in the northern half of the State. During the autumn of 1892, however, the writer was detailed to collect soils and prepare a soil map of Illinois for the Illinois Board of World's Fair Commissioners. This study necessitated a reconnaissance of the southern portion of the State. This reconnaissance has been supplemented by more detailed studies in 1894 and 1896. The field work carried on by the writer in the region under discussion has been done mainly in the field seasons of 1886, 1887, 1892, 1894, 1896, and 1897. In the intervening years the same line of study was extended into bordering districts, and the broadening of the field has resulted in a better understanding of the features of this region. In the preparation of this report, and also throughout the field study. Professor Chamberlin has given constant advice and direction. The report really embraces the information obtained by Professor Chamberlin in his early reconnaissances, and the best fruits of his wider studies, and of the studies of his other associates, as well 'Eighth AnD. Kept. U. S. Geol. Survey (for 1886-87), 1889, p. 141. 4 THE ILLINOIS GLACIAL LOBE. as the data directly obtained by the writer. It is with gratitude as well as with pleasure that this acknowledgment of indebtedness is made. In this investio-atiou there have been several distinct lines of observa- tion, which supplement one another in throwing light upon the glacial succession. (1) The work began with a mapping of moraines, and this map- ping has been can-ied to completion, i. e., each moraine has been followed thi'oughout its entire course with sufficient zigzagging to leam its breadth and general features as well as the position of the crest. (2) With this study of the moraines there has been carried on an investigation of the stratigraphy of the drift, shown by well sections or other exposures, both artificial and natural. Several thousand well sections have been collected, many of which appear in tabulated form in this report. The mode of deposition of the glacial drift is such that a simple study of the drift sheets in a vertical series can not, in many cases, furnish index of the glacial suc- cession. The mapping of the moraines has often aided greatly in working out the full glacial succession. (3) Coupled with the stratigraphic study and the mapping of the moraines there have been a few measurements and estimates of the relative amounts of erosion or other surface changes in the drift in different parts of the drift-covered area, a study which aims to throw light upon the relative ages of different drift sheets. Since the townships are frequently referred to by number and range, rather than by the civil name applied to them, a brief explanation of the method of numbering townships in this region is here presented, together with a map (PI. II) showing base lines and principal meridians. The expla- nation begins with the Second Principal Meridian adopted by the United States Land Survey, since the First Principal Meridian (which follows the State line of Ohio and Indiana) was not used as a basis for laying' out any portion of the region under discussion. The Second Principal Meridian leads north to south through west- central Indiana from the line of Michigan to the Ohio River, and is situated about 2 miles east of longitude 86° 30' west from Grreenwich. The base line crosses the southern portion of Indiana within 1 or 2 miles south of latitude 38° 30'. The townships are numbered both north and south from this base line. The State of Indiana only extends to T. 9 S., but reaches T. 38 N. of the base line. The ranges ai-e numbered both east and west from the Second Principal Meridian. Tliose on the east extend to the State U.S. GEOLOGICAL SURVEY. MONOGRAPH XXXVIII PL. II JULIUS Bl EN SCO. LITH NY INTRODUCTION. 5 line of Indiana and Ohio, while those on the west have an irregular boundary. From the head of Lake Michigan southward nearly to latitude 41° the west boundary is at the State line of Indiana and Illinois, but south from this line it extends west into Illinois about 25 miles, being very near longitude 88°. The Third Principal Meridian leads north from the mouth of the Ohio River to the Wisconsin line. It is about 8 miles west of longitude 89°. The base line is a direct continuation of the base line of the second merid- ian survey in southern Indiana. It enters Illinois from Indiana just north of the city of Mount Carmel and touches the south part of Centralia and Belleville, coming to the Mississippi River immediately below St. Louis. There are 17 townships south of the base line and 46 north of it. From the north line of the State soiith to the Illinois River at Peru the ranges lie entirely east of the Third Principal Meridian, but south from that stream the ranges are numbered both to the east and to the west. To the east they extend to the western limits of the survey based on the Second Principal Meridian; to the west they extend to the Illinois River above the mouth of that stream and to the Mississippi River south from the mouth of the Illinois. The Fourth Principal Meridian leads fi-om the Illinois River at Beards- town north to the Mississippi River about 8 milefe above Rock Island, and is continued in western Jo Daviess County. The base line leads directly west from Beardstown to the Mississippi River, 6 miles above Quincy, and is situated about 2 miles north of the fortieth parallel of latitude. The townships south of the base line reach the number 14, while those north reach 29. The ranges are numbered both to the east and to the west of the principal meridian, north from Beardstown; south from that city they are numbered only to the west. In Iowa and Missouri, together with several other States west of the Mississippi, the land surveys are governed by the Fifth Principal Meridian, which leads from the mouth of the Arkansas River north through eastern Arkansas, eastern Missouri, and eastern Iowa. The base line crosses cen- tral Arkansas, passing just south of the city of Little Rock. From this base line the townships are numbered to the south as far as the line of Arkansas and Louisiana. They are numbered to the north as far as the international boundary in western Minnesota and north Dakota. Eastern 6 THE ILLINOIS GLACIAL LOBE. Minnesota and Wisconsin are laid out from the Fourth Principal Meridian, the townshijis being numbered from the State line of Illinois and Wisconsin northward to the international boundary in Minnesota and Wisconsin, and to the line of Michigan and Wisconsin in eastern Wisconsin. The State of Michigan is laid out from the Michigan meridian, which leads from Sault Ste. Marie south to the Ohio State line. The base line follows the parallel 42° 30'. The numbering of townships north from the base line harmonizes with those laid out from the Fourth Principal Meridian in Wisconsin and Minnesota. The ranges are numbered both to the east and to the west of the principal meridian as far as the limits of the State. In each township there are 36 sections, numbered back and forth in tiers of six, the numbering beginning at the northeast and terminating at the southeast corner of the township. CHAPTEE II. PHYSICAL FEATURES. Before eutering upon a discussion of the glacial deposits, tlie leading physiograpliic features of the region will be outlined. The region invaded b}^ the Illinois lobe occupies the midst of the great interior basin which on the east rises to the Appalachian Mountains and on the west to the Rocky Mountains. The State of Illinois has the distinction of being the lowest of the North-Central States. Its mean elevation has been estimated by Mr. Hemy Gannett to be about 600 feet above tide, while that of Indiana is 700 feet, Michigan 900 feet, Wisconsin 1,050 feet, Iowa 1,100 feet, and Missouri 800 feet' Including the south end of the Lake Michigan basin, the region cov- ered by the Illmois lobe shows a range of not far from 1,200 feet, the bottom of the lake opposite Racine, Wisconsin, being at sea level, while the highest rock surfaces of Illinois covered by glacial drift are nearly 1,200 feet above sea level. It is not unlikely that glacial erosion and differ- ential depression have increased this range, but there is reason to think that in preglacial times the lake basin was at least several huudi-ed feet lower than the highest ridges of the border districts and that it had a controlling influence upon the course of the ice movement.^ The State of Illinois has been covered by a careful barometric survey conducted by Prof C. W. Rolfe, of the University of Illinois, a survey which had for its object the preparation of a topographic model of the State for the Columbian Exposition. Professor Rolfe used as datum points the altitudes of railway stations which had been determined by surveyor's level. These are found at intervals so frequent in nearly every county of the State that there is but little room for error in his maps. He has exercised great 'The average elevation of the United States, by Henry Gannett: Thirteenth Ann. Rept. U. S. Geol. Survey, 1892, p. 289. = See discussion by R. D. Irving: Geol. of Wisconsin, Vol. II, 1877, pp. 632-634. Also T. C. Chamberlin: Ann. Rept. AVisconsin Geol. Survey, 1878, pp. 23-32. 8 THE ILLINOIS GLACIAL LOBE. care in reducing to a minimum eiTors arising from barometiic fluctuations. He has kindly allowed the writer to trace from liis unpublished map sheets such contours as are represented on the accompanying map (PI. III). In the hilly-driftless tracts in the northwest corner, and in the southern end of the State, the sm-face is so uneven that only 100-foot contom-s are intro- duced. But the altitude of the greater part of the State is represented by contours Avith 50-foot interval. For very small areas, covering but a frac- tion of a square mile, the contours must necessarily be omitted on a map of so small scale. A few such areas occur in the hilly disti-icts in the noi-th- westem and the southern portions of the State. In PL IV the areas between each 100-foot contour are shown m color, and the bottom of Lake Michigan is also represented. In a general way the altitude decreases from north to south in the State of Illinois, there being four counties on the north border (Jo Daviess, Stephenson, Boone, and McHemy) in which points rise 1,000 feet above tide. Near the southern border of the Coal Measures basin the average altitude is below 500 feet. There is, however, south from the Coal Meas- ures basin a prominent ridge which rises neai-ly to the altitude of the northern portion of the State, its crest reaching at one point an altitude of 1,047 feet (Rolfe). A reference to Pis. Ill and IV will make cleai' the altitudes and slopes of Illinois and also of the portions of southwestern Michigan and western Indiana embraced in this discussion. The highest point in Illinois (1,257 feet) is Charles Moimd, on the Illinois- Wisconsin line, in the northwest county. The lowest points are near the junction of the Ohio and Mississippi, and fall slightly below 300 feet at low-water stages of the sti'eam. At high-water stages none of Illinois is below 300 feet. It appears from the table below (p. 12) that only 125 square miles, or an area of less than four townships, rises above the 1,000-foot contoiu-, and that only 10,747 square miles, or less than one-fifth of the State, falls below the 500-foot contour. About 20,000 square miles, or more than one-third of the State, stands at 600 to 700 feet above tide, or at about the average altitude of the State. The thickness of the di-ift is so great in the northeastern fourth of Illinois as to convey a false idea of the altitude of the rock surtace in that i:egiou. Were the tbift coating entirely removed, the average elevation would prob- ably be as low as the surface of Lake Michigan (580 feet above tide), and 'H >^ ui s 9 •^ 3 Hi ifiiii ? S5 ie3i»>Q.a.ia-jSoo>''iolinT_iIo*oa.oo«;iicia.in5> o ^ -g J= Tj "^ ^o 3 O I I — I I— ' H O C r. o PHYSICAL PBATUEBS OF THE EEGION. 9 possibly it would not exceed 500 feet above tide. This low altitude extends eastward some distance into Indiana. The low altitude of this district, as well as that of the Lake Michigan basin, as noted above, probably influ- enced the ice flow and invited its great southward extension in the State of Illinois. The following table showing the range in altitude of the drift surface and of the rock floor in each county of Illinois serves to show not only the general range but also the variations within small districts. As the impres- sion prevails widely that Illinois is a very level region, the table may be of service in dispelling this illusion. The impression of flatness arises from the general absence of abrupt reliefs. A comparison of the ranges in altitude iu the several counties shows that 18 counties have a range of over 400 feet in their drift surface and that 22 show an equally great range in rock surface. In 55 coiinties, or more than half the number in the State, there is a range of less than 300 feet in the drift surface, while in 62 coun- ties the known range in rock surface falls below 300 feet. In the remaining 29 counties the range in altitude of drift surface falls below 200 feet. Table showing altitudes of drift surface and rock floor, icith their range, in each county of Illinois, (a) County. Highest point. Highest known rock surface. Lowest point. Lowest known rock surface. 1,257 1,257 575 453 1,170 1,170 735 (500) 990 975 680 (425) 1,040 1,000 720 (450) 1,040 875 740 580 913 607 581 505 910 699 581 478 812 680 581 581 975 760 614 579 950 813 649 542 1,000 1,000 660 (400) 1,017 875 649 (400) 1,020 1,000 568 435 890 850 564 435 840 675 530 (425) 857 736 523 (385) 850 815 562 560 987 800 431 330 Kange in drift sur- face. Range in rock sur- face. Jo Daviess . . Stephenson. . Winnebago. . Boone McHenry Lake Cook Dupage Kane Dekalb Ogle.... Lee Carroll Wbiteaide... Eock Island - Mercer Henry Bureau (?) 435 310 320 300 332 329 231 361 301 340 360 452 326 310 334 288 556 804 (670) (550) (550) 295 102 221 99 181 271 (600) (475) 565 415 (250) (351) 255 470 a Altitudes of rock surface in parentheses have been inferred from known altitudes in bordering counties. 10 THE ILLINOIS GLACIAL LOBE. Table showimj altitudes of drift surface and rock floor, etc. — Continued. County. Putnam Lasalle Kendall Grundj- Will Kankakee Iroquois Ford Livingston . . . McLean Tazewell Woodford Marsball . Stark , Peoria Knox Warren , Henderson . . . Hancock McDonough . Fulton Adams Schuyler Brown Mason Cass Menard Logan Dewitt Macon Piatt Champaign . A'^ermilion ... Edgar Clark Cumberland . Coles Douglas Moultrie Shelby Christian .. . Sangamon . . . Highest point. 740 930 760 700 820 750 780 840 840 913 820 830 895 850 835 850 810 770 765 775 750 750 750 807 650 690 650 744 800 760 820 830 790 839 770 700 799 725 750 770 750 721) Highest known rock surface. 565 680 640 552 700 690 615 561 688 700 575 621 585 800 780 800 750 670 685 680 740 735 645 710 371 550 600 550 541 556 480 676 650 652 620 600 635 481 490 625 650 707 Lowest point. Lowest known rock surface. 430 433 540 477 485 550 650 650 588 650 425 429 430 620 425 536 (?) 505 46S 500 422 452 417 414 420 415 445 520 585 550 600 610 480 480 430 510 575 610 560 490 530 512 330 330 509 465 485 538 260(?) 350 365 469 — 325 (325) (325) 600 341 536 450 (375) (375) 500 (325) (350) (345) (345) (325) 345 (325) 379 — 359 — 400 480 440 436 480 (355) 510 — 538 — 481 490 538 — 497 512 Range in drift sur- face. (? 310 497 220 223 335 200 180 190 252 263 395 401 465 230 410 314 :?) 265 297 275 328 398 333 393 230 275 205 224 215 210 220 220 310 359 340 190 224 115 190 280 220 208 Bange in rock sur- face. 235 350 131 97 215 152 355(?) 211 323 231 + 250 (296) (260) 200 439 264 300 (295) (310) 180 (415) (385) 300 (365) (46) 205 (275) 171 + 182 + 156 (f^ 236 214 172 (265) 90 + 97 + (?) (?) 87 + 135 195 PHYSICAL FEATURES OF THE REGION. 11 Table showing altitudes of drift surface and rock floor ^ etc. — Continued. County. Morgan Scott Pike Calhoun Jersey Greene Macoupin — Montgomery Madison Bond Fayette Effingham... Jasper Crawford -.. Lawrence Richland Clay Marion Clinton St. Clair .... Monroe Randolph ... Washington . Perry Jefferson Wayne Edwards Wabash White Hamilton ... Franklin Jackson Williamson . Saline Gallatin Hardin Pope Massac Johnson Union Alexander... Pulaski Highest point. (? 737 714 880 810 830 :?) 740 750 650 675 650 680 660 590 500 590 650 650 570 758 750 712 580 575 620 540 560 615 590 616 550 860 750 864 810 810 :,047 550 800 985 619 489 Highest known rock surface. 665 637' 800 775 800 616 672 662 600 600 600? 650 600 550 490 510 600 G35 500 735 740 675 580 575 600 430 560 615 590 616 500 850 750 864 810 810 ■1,047 550 800 985 619 489 Lowest point. 413 410 408 403 391 404 500 530 381 450 435 476 410 400 391 385 396 435 378 375 360 340 378 385 415 368 370 365 323 340 380 323 370 350 304 298 290 280 335 296 279 279 Lowest known rock surface. (345) (345) 325 - (300)- (300) (300) 440 - 527 284 351 405 476 - 395 - 350 (345) 385 - 396 - 379 375 - 284 350 - 340 - 375 - 380 - 415 - 368 - 344 - 344 - 323 - 340 - 375 - 318 - 370 - 345 - 240 290 - 280 - 270 - 330 - 260 - 270 - 270 - Eange in drift sur- face. (? 324 ■304 472 :?) 439 (?) 240 220 269 225 215 204 250 190 109 205 254 215 192 383 390 372 202 190 205 172 190 250 267 276 170 (?) (?) (?) (?) Eange in rock sur- face. (320) (292) 475 + (475)+ (500) (316) 232 + 135 316 249 195 174 + 205 + 200 (145) 125 + 204 + 256 125 + 451 390 + 335 + 205 + 195 + 185 + 162 + 216 + 271 + 267 -f 276 + 125 + 532 + 380 + 519 + 570 520 + 767 + 280 + 470 + 725 + 349 + 219 + 12 THE ILLINOIS GLAGIAL LOBE. From Professor Rolfe's maps estimates have been made of the areas between each 100-foot contom- in each county, and the results combined for the entire State. By these estimates the average altitude of the State is 633.55 feet, or but a few feet different from the estimate made by Mr. Gannett. The average thickness of drift in the State is estimated to be between 100 and 130 feet. (See discussion, Chapter XIII.) If the thick- ness of the di-ift be deducted, the average altitude of the rock sm-face in the State will be about 525 feet, or fully 50 feet below the surface of Lake Michigan. The following table gives the estimated areas between 100-foot contours for the entire State: Estimated areas in Illinois heticeen 100-foot contours. Square miles. Above 1,200 feet 1 Between 1,100 and 1,200 feet 6 Between 1,000 and 1,100 feet 118 Between 900 and 1,000 feet 1 009 Between 800 and 900 feet 3' 981 Between 700 and 800 feet 11,127 Between 600 and 700 feet 20 058 Between 500 and 600 feet 9 603 Between 400 and 500 feet 8 822 Between 300 and 400 feet 1^ 925 Area of Illinois 56, 650 As noted above, the Illinois lobe extended into western Micliig-an and western Indiana, and also into southeastern Iowa. Contour maps of these districts have not yet been made, except in portions of Scott and Muscatine counties, Iowa, covered by the United States Geological Survey sheets. The numerous railway surveys have, however, established the altitude of so many points that a fair estimate of the altitude of these districts ma)- be made. It is found that the drift surface has an average altitude slightly higher than that of Illinois, but it will scarcely exceed 650 feet above tide. The rock surface, on the other hand, appears to be a few feet lower than the average for Illinois. The inclusion of these districts, therefore, scarcely makes a measurable change in the average altitude of the region covered by the Illinois lobe. But if the Lake Michigan basin be included, it wil' materially lower the average altitude. Profiles across the basin of Lake Michigan have been prepared from Lake Survey charts which bring out certain prominent features of the southern end of the Lake Michigan basin as it now appears with its coating U.S. GEOLOGICAL SURVEY MONOGRAPH XXXVIH.PL.V. Profile across Lake Michigan in latitude 44-° 15' Pleistocene 640 feet Davonian shale320 feet Devonian /imestone Surface of lake 573.6 feet Profile across Lake Michigan from Sheboygan to Little Sable Point 'BE^ONHARaOR Surface of lake 573.6 feet POSITIONS OFSECTIONS J ^Muske^nUk8% . ^ecfoflakP. Pleistocene Eo-Carboniferous \Dnrt22S feat irly sandstone Profile across Lake Michigan from Port Washington to Muskegon Surface of lake 579.6 feef. Bedof fakf> istSceneSZAOrift 179 fbet miferous^ — ^Sane/stone 76 Sandstone 76 feet Profile across Lake Michigan from Milwaukee to Grand Haven Surface of lake 573.6 feet. Profile across Lake Michigan from Racine to Holland t I ^ ?s^> ^ Q, <: <5!?? ^ Surface of lake 573.6 feet Profile across Lake Michigan from Fox Lake to Keeler ■u JO ti Upper Silurian). LowerSilurian\ Surface of lake 579.6 feet •roup 'ver ^roup 'fnestone Bed of take Ydh^4- I Blue shafe \Black sttale A/iamilton limestone Profile across Lake Michigan from Chicago to Benton Harbor JULIUS Bl EN & CO, LITH. N.> PROFILES ACROSS THE BED OF LAKE MICHIGAN (Based on soundings given in the UnitedStateslake SurreyCharts ) BY FFIANK LEVERETT 1898. PHYSICAL FEATUEES OF THE REGION. 13 of drift (see PI. V). The first two profiles show a gradual slope from the west side to points beyond the middle of the lake, followed by a somewhat abrupt rise to the east shore. The amount of di-ift on the east shore is somewhat greater than on the west, the rock floor at St. Joseph being but 466 feet above tide, or 124 feet below the lake, while on the west shore it rises in many places 20 or 30 feet above the lake level and generally is not far below it. The next profile leading eastward from Racine passes across the deepest part of the basin in the southern end of Lake Michigan, and shows no essential difference on opposite sides of the lake in the slope of the lake bottom. The slopes and bottom are A^ery smooth compared with those shown in profiles farther north. The profile leading from Milwaukee to Grand Haven shows a much shallower part of the basin than that east from Racine, the altitude being nowhere below 200 feet above tide, while opposite Racine it reaches sea level. This line between Milwaukee and Grrand Haven seems to mark nearly the summit of a ridge between two basins, both of which, together with the dividing ridge, are covered by the lake. In the profile a few miles to the north, leading from Port Washington, Wisconsin, to Muskegon, Michigan, the lake bottom is shown to be singu- larly irregular. The appearance presented is that of a series of escarp- ments facing westward, similar to the escarpment of Lockport (commonly known as Niagara) limestone a short distance west from Lake Michigan, biit it is not entirely certain that they are rock escarpments. Were the drift to be removed from the eastern border of the basin the profile would be quite different. A well at Muskegon, reported by the Michigan Geo- logical Survey, has 235 feet of di'ift, which brings the rock floor down to an altitude but 360 feet above tide, or only a few feet above the crests of the ridges in the midst of the lake. The dotted line at the right of the profile indicates the depth of the di-ift at that point. The profiles north from this line show irregularities of lake bottom which give it the appear- ance of being channeled longitudinally. Whether these irregularities are due to drift accumulations or to rock ridges is not manifest fi-om an inspec- tion of the lake charts. The remarkable thickness of drift at Manistee (640 feet) is worthy of note, and indicates that the abrupt border of the lake there is of diift. Evidence that the present smooth bottom of the Lake Michigan basin in its southern end is due to the planeness of the drift surface instead of the 14 THE ILLINOIS GLACIAL LOBE. smootliness of the rock floor is found in borings near Michigan City. Three borings in a line leading ft-om Michigan City westward 2 miles show a ridge capped by Devonian shale at the middle boring, which stands 70 or 80 feet above a rock floor of limestone at the other wells. Taking the basin as a whole, interesting contrasts appear. The remai-kable depth and the smoothness of the south-central portion of the basin shown in the profile east from Racine seem to favor the view that glacial erosion was there an agency of much consequence. The preserva- tion of the shale at Michigan City (a few miles to the south) and the apparent preservation of old escarpments in the midst of the basin a few miles to the north, both being in more prominent and apparently better exposed situations for eff'ective erosion than the deep part between them, seem to show comparatively little erosion. The evidence therefore as to the amount of glacial erosion is somewhat confusing, and it will be found difficult to eliminate this factor if an attempt to restore the preglacial features of the basin be made. The reliefs of the region covered by the Illinois lobe are seldom of a bold or conspicuous type. On the contrary, they are so gradual as to give the impression that they are less than the instrumental determinations indi- cate. There are, however, a few ridges with rock nuclei which are of sufficient prominence to merit notice. The most prominent ridge of the region is found in the southern por- tion of Ilhnois, at the southern border of the glaciated district. This ridge crosses the State in a direction nearly due east and west from the bend in the Ohio River just south of the mouth of the Wabash to the Mississippi River near Grand Tower. Its crest ranges from about 700 to 1,047 feet above tide (Rolfe), and its breadth ranges fi-om 5 or 6 to 10 or 12 miles. It stands 300 to 600 feet alcove the lowlands on the north, their altitude being but 400 to 550 feet above tide, and an even greater amount above the lowest parts of the district on the south. This ridge seems to have limited the extension of the ice sheet, for the di-ift was carried well up toward the crest on the north slope, but no decisive e^^dence has been found that the crest was overridden. From the western end of the ridge just noted, northwestward along the Mississippi to St. Louis, an elevated limestone belt separates the river valley from the Coal Measm-es district to the northeast. This belt is but PHYSICAL FEATURES OF THE EEGION. 15 5 to 10 miles wide and stands 650 to 750 feet above tide, while the Coal Measures district bordering it stands only 450 to 600 feet above tide. It is inteiTupted by gaps 2 miles or less in width where the Big Mnddy and the Kaskaskia pass tlii-ough it to the Mississippi ; otherwise it forms a continuous belt. Its altitudes are no greater than those of the district across the river in Missouri. On the contrary, there is a rise in that direction to the Iron Mountain district of southeastern Missouri. It seems remarkable that the Mississippi should have taken a course across this limestone belt, and as yet no satisfactory explanation for this feature has been found. The stream is apparently in a preglacial valley. Its course seems, therefore, to be inde- pendent of glaciation. This belt, like the ridge of southern Illinois, seems to mark the limit of the ice sheet. Drift in small amount occurs over most of its surface, but, so far as known to the writer, does not extend beyond the Mississippi. Near St. Louis, however, where the limestone border passes to the west side of the river, drift is found in small amount. Passing up the Mississippi to the mouth of the Illinois, a naiTow axis of upheaval is found, trending nearly east and west, along which the altitude is somewhat greater than on bordering districts. Just east of the mouth of the Illinois there are a few points where the rock surface rises to about 800 feet, while on the plain north of this ridge the rock scarcely exceeds 650 feet. West from the Illinois the altitude is not markedly greater at this axis than to the northward, there being a narrow limestone ridge between the Mississippi and the Illinois through the entire length of Calhoun County, whose crest is generally 700 to 750 feet above tide. The altitude of the ridge west of the Illinois is fully 100 feet greater than that of the bluffs immediately east of that stream. These elevated limestone ridges, and similar ridges on the Missouri side of the Mississippi, near the town of Louisiana and soiithward, carry very little drift and, as noted some years since by Salisbury, may not have been completely covered by the ice sheet.^ Of the three belts just described two have been sculptured very deeply by surface erosion, viz, the ridge crossing southern Illinois and the ridge near the mouth of the Illinois. The remaining belt (along the Mississippi below St. Louis) is less deeply sculptured because in much of its extent imderground drainage through sink holes and caves has been established. 1 Proc. Am. Assoc. Adv. Sci., Vol. XL, 1891, pp. 251-253. 16 THE ILLINOIS GLACIAL LOBE. There is not even a well-developed system of ravines and tributaries on its surface, but ravines partially developed often discharge their waters into sink holes and have no surface indications of connection with other lines of di-ainage. In the northwestern part of Illinois a few conspicuous outlying mounds of Lockport (Niagara) limestone appear. Some of these are situated in the di-ift-covered region and others in the Di'iftless Ai-ea. They rise 75 to 300 feet above border districts. The majority of these mounds rise above the 1,100-foot contour, and one of them, Charles Mound, as noted above, forms the highest point in the State (1,257 feet). They vary in size from a fraction of a mile to several square miles. In the latter case a chain of mounds occurs, rather than a single mound or ridge. These mounds lie but a few miles north and east of continuous Niagara formations and were apparently once joined with them, then- separation, as long since stated by Worthen, being due to denudation.^ The greater pai't of the district among these mounds has been denuded of the Hudson River or Maquoketa shales as well as of the Lockport limestone, thus exposing the Galena limestone. East from the district just discussed is the broad drainage basin of Rock River, which has no conspicuous ridges or remnants of higher sti-ata capping its present smface formations, though the latter are thoroughly sculptured by di-ainage lines. Between the Rock River di-ainage line and Lake Michigan there is a somewhat elevated belt of limestone, wliich extends cm-vingly in a dnection east of south into western Indiana. It is generally so hea-saly covered with drift that its lesser features can only be conjectured. Borings indicate that A^ariations of 100 feet or more in altitude occur within a distance of a few rods. It was in all probability thoroughly sculptured by drainage lines. The rock surface has its greatest altitude at the north, being 400 feet above Lake Michigan at tlie Illinois- Wisconsin line, while in the "^acinity of the Indiana line it rises only 100 to 200 feet above the lake. The Fox, Des Plaines, and Kankakee rivers now cross this limestone belt from the k)w belt bordering Lake ]\Iichigan into the old Rock and Illinois drainage basin, thus extending the latter at the expense of the former. In southern Indiana there is a comparatively elevated region along the east border of the Coal Measm-es formed largely by the Conglomerate ' Geology of Illinois, Vol. T. ISOfi. ,i. 4. PHYSICAL FEATUEES OP THE KEGIOF. 17 sandstone. This was partially covered by the ice sheet. The highest points within the glaciated portion seldom, if ever, exceed 900 feet, but with this altitude they stand 200 to 300 feet or more above the general level of the rock surface near the Wabash, only a few miles to the west. This sandstone forms the western border of a broad tract of elevated land, which is greatly eroded and hence is called the "hill country" of Indiana. Its northern portion has had the irregularities greatly softened by glaciation. The southern portion was less heavily glaciated and is nearly as rough as the unglaciated tracts. The district occupied by the Coal Measures, both in Illinois and in Indiana, has a general altitude somewhat lower than that of the bordering- limestone or sandstone. Prior to the ice invasion its surface had been greatly eroded, leaving narrow divides at the water partings more or less dissected into low hills, while the streams occupied broad shallow troughs. These features are only partially concealed in southern Illinois and south- western Indiana. As already noted, streams which flow from the Coal Measures into the lower Carboniferous limestone show a marked reduction in the size of the channel upon entering the limestone. This is true not only of small rivers like the Kaskaskia, but also of large streams. The valley of the Illinois is reduced in breadth from 8 or 10 miles to scarcely 3 miles on entering the limestone on the border of Pike and Greene counties. The preglacial Mississippi, now partly filled with drift, is narrowed in breadth from 10 or 12 miles, or possibly 15 miles, in the Coal Measures of Louisa County, Iowa, and Mercer County, Illinois, to only 5 or 6 miles on entering the limestone a few miles above Burlington, Iowa. Where streams do not enter the limestone a gradual widening occurs toward the mouth. The Wabash occupies a preglacial valley in which the breadth increases gradually southward and reaches 10 or 15 miles in the vicinity of its mouth. Below Terre Haute the breadth varies from 5 or 6 miles to 15 miles or more, and in places the bluffs are very poorly defined, owing- to the fact that the strata of the bordering districts have broken down nearly as rapidly as the valley was deepened. The several tributaries of the Wabash in southern Illinois — the Embarras, Bon Pas, and Little Wabash — have broad trough-like valleys 2 to 4 miles in Avidtli in their lower courses, and their bluffs are often vaguely defined, like those of the main stream. MON xxxviii 2 18 THE ILLINOIS GLACIAL LOBE. Occasional basin-like expansions of river valleys appear outside the Coal Measures. One formed in the Hudson River or Maquoketa shales and underlying- formations along the Pecatonica Ri-\-er near Freeport has a breadth of about 4 miles where Avidest, though usually it is but 2 or 3 miles. This basin has been discussed recently by Mr. Oscar Hershey as a peneplain/ but to the writer it appears too immature to be thus classed. A similar basin borders Elkhorn Creek in Carroll and Whiteside counties. The Mississippi Valley also has an expansion where it crosses these shales on the borders of Carroll County, Illinois, and Jackson County, Iowa, being fully twice as wide as it is where cut in the Galena or in the Lockport (Niagara) limestone. These contrasts in width are well shown in the Clinton, Savannah, and other topographic sheets coA'ering this part of the Mississippi Valley. The Clinton sheet appears as PI. XVIII of this report. Most of the streams in this region have courses independent of the preglacial drainage lines. It is only in the western half and southern third of Illinois and in southwestern Indiana, where the drift is compara- tively thin, that the course of preg'lacial drainage can be confidently indi- cated. Even here the larger valleys only are traceable, for the valleys of the smaller streams have usuall}^ been completely filled, and deep borings are too few to supply data to map out their position and connections. The effect of glaciation on the drainage will appear in the progress of the discussion. ' Am. Geologist, August, 1896. CHAPTER III. OUTLINE OF TIME RELATIONS OR GLACIAL SUCCESSION. In the progress of the studies of glacial deposits the complexity of the glacial histor}^ has been graduallj- unfolded. After the abandonment of the iceberg hypothesis, the early students approached the study with the hypothesis of a single and practically continuous period of deposition, in which the ice sheet at one time covered the entire glaciated area. This period was supposed to have terminated with a suigle high stage of water, attending the melting of the ice, which was termed the Champlain epoch. It soon became apparent that this simple hypothesis could not be made to cover the complicated glacial history. Evidences of a succession of reces- sions and advances of the ice sheet have appeared, and a sharp controversy has arisen concerning the importance of these oscillations, it being held by some students that they are of minor importance and mark short or partial retreats and advances in a single epoch of glaciation, while others have contended for the necessity of recognizing two or more ice invasions between which were very extensive and prolonged deglaciation intervals. The studies upon which the present report is based have developed evidence which, it is thought, has an important bearing upon the question in dispute. The writer, like others who have studied this region, has been greatly impressed with the evidence of prolonged intervals of deglaciation, and an attempt will be made to set forth the nature of this evidence. The several sheets of glacial drift which this and neighboring regions contain have received geographic names, as have also some of the inter- glacial beds. Names of this class were proposed by Chamberlin as a sub- stitute for time phrases which had arisen and which were of controverted application.^ They have already come into wide use in g'lacial literature, and are employed by students who hold the divisions to be of minor impor- tance as Avell as by those who consider them of great importance. The ' See Geikie's Great Ice Age, third edition, 1894, pp. 754-774. Also Jour. GeoL, Vol. Ill, pp. 270-277, aud Vol. IV, pp. 872-876. 19 20 THE ILLINOIS GLACIAL LOBE. cli%asions to which ChamberUn has appKed names appear to have the rank of the main divisions of the Glacial period, whatever that rank may prove to be. Other names are necessary to denote the subdivisions. In the present report several names are thus introduced to designate the moraines associ- ated with the older as well as the newer sheets of drift. The name selected is usually that of a town located on the moraine. In most cases the names have come into use in the office and in correspondence with other glacialists, as a convenient form of reference. The selection thus made seems suitable for general use. In the outline sriven below it is aimed to cover the events between the deposition of the oldest-recognized drift sheet in North America and the final recession of the ice sheet or sheets into the region north of the Great Lakes. The main divisions appear to be much longer than the secondary ones. It is concerning the former that the value of time intervals is a mat- ter of dispute. The secondary divisions of the drift deposit are not thought by any students to be marked by intervals sufficiently prolonged to mei-it the application of the term epoch. It is probable, however, as shown farther on, that some oscillation of the ice front occurred, so that the moi-aines on which these subdivisions are based do not mark simply halts in the recession of the ice, but rather readvances after recessions of minor consequence. To avoid the use of the controverted term epoch, it is thought best to employ the term stage, which gives a less definite time value. Outline of the drift sheets and intervals. Stage 1. Oldest recognized drift sheet — the Albertan of Dawson, including, also, the sub-Aftonian of Chamberlin. Stage 2. First interval of deglaciation— Aftonian of Chamberlin. Stage 3. Kansan drift sheet of the Iowa geologists. Stage 4. Second interval of recession or deglaciation — Yarmouth of Leverett. Stage 5. niinoian drift sheet. Stage 6. Third interval of recession or deglaciation — Sangamon of Leverett. Stage 7. lowan drift sheet and main loess deposit. Stage >i. Fourth interval of recession or dealaciatiou — Peorian of Leverett, possibly equivalent to the Toronto Formation of Chamberlin. Stage 9. Early Wisconsin drift sheets. „ , . , c, 1, -11 • ■ J. „ ( Shelhyville moraine. Substage 1. Shelbyville morainic system | gerro Gordo moraine. ( Outer ridge. Substage 2. Champaign morainic system-? Middle ridge. ( Inner ridge. ( Bloomingtim or outer main ridge. Substage 3. Bloomiugton morainic system •] Normal or inner main ridge. ( Subordinate ridgos. „ , ^ . ,. n ■ • ,. S Marseilles moraine. Substage 4. Marseilles moraimc system ^ p„gsi,,,y Miuooka till ridge. TIME EELATIONS OR GLACIAL SUCCESSION. 21 Stage 10. Fifth interval of recession, unnamed; shown by shifting of ice lobes. Stage 11. Late Wisconsin drift sheets. Substage 1. Great bowlder belts and accompanying moraines, including, perhaps, the Minoota till ridge. Substage 2. Valparaiso morainic system. ^ Substage 3. Lake border morainic system. Stage 12. Lake Chicago submergence. Stage 13. Emergence of plain covered by Lake Chicago. Stage 14. Partial resubmergence of plain covered by Lake Chicago. Stage 15. The iiresent stage of Lake Michigan. The outline just presented differs from the one last presented by Chamberlin^ in the separation of the Wisconsin drift series and lake history into the several substages, and the introduction of names for three inter- glacial stages. Except for the introduction of names for the interglacial stages, it is essentially the same as an outline presented by the writer in a recent bulletin of the Chicago Academy of Sciences.^ Mr. J. B. Tyrrell of the Canadian Geological Survey, who has studied widely in western Canada, favors the separation of the Albertan and sub- Aftonian stages. In a letter to the writer dated July 9, 1897, which discusses the outline given in the bulletin just referred to, he makes the following statement: The Albertan drift sheet of Dawson is older than any till of the Keewatin glacier seen in the plains of northwestern Canada, while the Upper and Lower Bowlder Clay of our Eeports seem to correspond closely with your Kansau and sub- Aftonian. I should, therefore, completely separate the Albertan and sub-Aftonian. In the present stage of investigation the correlation of the Upper and Lower Bowlder Clays of the Canadian Reports with the Kansan and sub- Aftonian of southern Iowa is not worked out satisfactorily. The full extent of either the Kansan or sub-Aftonian in districts lying between Iowa and the Canadian boundary is not determined. It therefore may be hazardous to venture definite correlation, though the balance of probabilities, as sug- gested by Tyrrell, seems to favor this correlation and the transference of the Albertan to an earlier stage. The complexity of the glacial history is still further increased by the occurrence of more than one gathering ground or center of dispersion of the ice. The explorations of the Canadian Survey have shown that there 'Jour. Geol., Oct.-Nov., 1896, Vol. IV, No. 7, pp. 872-876. 2 Pleistocene features and deposits of the Chicago area, by Frank Leverett : Bull. Chicago Acad. Soi. No. 2; issued May, 1897. 22 THE ILLINOIS GLACIAL LOBE. were three main centers of dispersion aside from Greenland. The Cordil- lei'au reg-ion of western Canada contained one ice field from which there was dispersion in all directions. The province of Keewatin, west of Hudson Bay, contained aiiother ice field which spread in all directions and reached the glacial boundar}^ in Missouri and States to the southwest. The third ice field occupied the highlands east and south of Hudson Bay. It spread to the borders of the Atlantic on the north and east, and to the borders of the Mississippi and Ohio on the southwest and south. The two ice fields bordering Hudson Bay probably for a time coalesced to form the Lauren- tide ice sheet of Dawson.-" But they were apparently distinct and inde- pendent centers for a considerable part of the Grlacial period. The names Keewatin and Labrador seem appropriate for these independent centers of glaciation, the former being a name proposed bj^ Mr. Tyrrell, and the latter one which has been used by several glacialists in correspondence and to some extent in print. The name Cordilleran has been applied by Dawson to the ice field in western Canada. There appeal's to have been less com- plete coalescence of this ice field with the Keewatin than that between the Keewatin and Labrador ice fields. The Cordilleran ice field, as shown by Dawson, occupied a portion of the Rocky Mountains and extended eastward into the pro-\dnce of Alberta, in the early stage of glaciation, when the Albertan drift sheet was deposited.- This advance long preceded the maximum westward extension of the Keewatin ice field. Whether the sub-Aftonian or any other deposits of the Keewatin ice sheet are as old as the Albertan, as noted above, is not satisfactorily determined. The Keewatin ice sheet apparently reached its farthest limits on the borders of the Mississippi at the Kansan stage of glaciation. The recogni- tion of the sub-Aftonian — an older deposit than the Kansan — in southern Iowa is based upon the exposures of this drift sheet under a somewhat fresher sheet of Kansan drift. The extent of the sub-Aftonian toward the south and west compared with that of the Kansan is not yet determined. In a paper presented at the twelfth annual meeting of the Iowa Academy of Sciences, in December, 1897, Dr. H. Foster Bain, of the Iowa Greolog ical Survey, gave a careful review of the features of the sub-Aftonian and 1 See Am. Geologist, Vol. VI, 1890, pp. 153-161. 2 Bull. Gool. Soc. America, Vol. VII, pp. 31-(5fi; issued November, 1895. TIME RELATIONS OR GLACIAL SUCCESSION. 23 descriptions of the weathered zone between this till sheet and the overlying Kansan. The extent of weathering appears to him scarcely sufficient to warrant a separation into a distinct glacial stage. He, however, suggested that the sub-Aftonian sheet may have been formed during one of the hypothetical minor advances of the ice sheet preceding its maximum extension.^ The portion of the Labradorian ice field to which the name Illinois Lobe is applied, reached its farthest limits on much, if not all, of its border at the Illinoian stage of glaciation. The lUiuoian drift sheet, as indicated in detail farther on, passed some distance into territor}^ which had been occu- pied by the southern extension of the Keewatin ice sheet at the Kansan stage. Since the Illinois ice lobe reached its farthest limits on much of its border at the Illinoian stage of glaciation, any earlier deposit made by this ice lobe must be largely concealed by the deposits of this stage. Attention is called below to deposits in Illinois which may prove to be sufficiently older than the Illinoian to be referable to a distinct stage, though the evidence as yet is rather fragmentary. Concerning this matter Professor Chamberlin has sug- gested^ that the two great ice fields may have alternated in their invasions in such manner that the sub-Aftonian preceded the sub-Illinoian and the latter preceded the Kansan, much as the Kansan is known to have preceded the Illinoian. There is, however, as yet no decisive e'sddence of such a rela- tionship. Possibly the sub-Illinoian will prove to be of about the same age as the Kansan. With these preliminary statements we pass at once to the discussion of the Illinoian stag-e of glaciation. > Proc. Iowa Acad. Sci., Vol. V, 1898, pp. 86-101. 'Communicated to the writer. CHAPTER IV. THE ILLINOIAN DRIFT SHEET AND ITS RELATIONS. GEN^ERAL STATEMENT. Relation to outlying and underlying drift. TllG fll'St reCOgnitioil Rncl SeparatiOll of the Illinoian drift sheet from an older sheet of drift which iinderhes it on the borders of the Mississippi was made by the writer in southeastern Iowa in the spring- of 1894. The occurrence of a bowlder of red jaspery con- glomerate in Lee County, Iowa, had been noted some ten years earlier, but its significance was not recognized at that time. It is now found that bowlders of this class are not rare, and that they are in all probability derived from the ledges north of Greorgian Bay. If so, they are an indica- tion that the southwestward movement of the ice from that region extended somewhat beyond the Mississippi River. The studies in 1894 developed other evidence that the invasion which brought in these bowlders from the northeast reached beyond the Mississippi, and that it occurred at a much later date than the general glaciation of southern Iowa and northei'u Mis- souri. The western limits of this ice invasion are plainly indicated by a marginal ridge. The evidence of a long interval is found in the greater erosion of the drift sheets outside the limits of the Illinoian, and in the prevalence of a soil horizon and weathered zone beneath the Illinoian sheet where it overlaps the earlier one. This interval appears to be of sufficient importance to be termed an intei'glacial stage and to justify the reference of the two sheets to distinct stages of glaciation. The intervening stage of deglaciation has recently been named the Yarmouth interglacial stage,^ and is discussed farther on. Relation to the lowan drift sheet. — The qucstiou ariscs wliethcr tlic lUiuoian sheet should be classed with the lowan sheet, which, as shown by McGee in the 'In a paper presented by the writer at the twelfth annnal moetiiig of tlie Iowa Ac.Tdoiuy of Sciences, December, 1897: Proo. Iowa Acad. Sci., Vol. A^ 1898, pp. 81-86; also Joiiv. Gcol., Vol. VI, 1898, j)p. 238-243. 2i '6. C B GENERAL ASPECTS OF ILLINOIAN DEIFT SHEET. 25 Eleventh Annual Report of this Survey and in earlier papers, is separated from the underlying drift of eastern Iowa bj^ a distinct soil horizon. It is found that a notable interval occurs between the deposition of the lUinoian sheet of drift and the deposition of the main sheet of loess of the Mississippi Basin, an interval indicated by erosion, weathering, and the formation of a soil horizon. But this sheet of loess seems to be intimately connected with the lowan drift sheet, as shown by McGree, a relation which subsequent studies by several independent investigators fully confirms. It appears, therefore, that the Illinoian drift sheet is separated by a notable interval from the lowan sheet as well as from the underlying sheets. Furthermore, a till sheet referred to the lowan stage is present in northern Illinois which falls far short of reaching the limits of the Illinoian till sheet. Like the lowan sheet of eastern Iowa, it is found to be contemporaneous with the main loess deposition. The interval between the Illinoian till sheet and the lowan loess and till has recently been named the Sangamon;^ it is discussed in some detail below. A deposit termed gumbo, which lies between the Illinoian till and the lowan loess, is also described. Culmination of the Illinois lobe at the Illinoian stage. At tlie time of tllC depOsitlOn of the Illinoian drift sheet the southwestward movement from Labrador and the heights south of Hudson Bay appears to have reached a limit in western and southern Illinois beyond any earlier invasion. It is not as yet certain, though it is quite probable, that the Illinoian sheet extends beyond all older sheets in northwestern Illinois and southern Wisconsin. In the absence of positive evidence to the contrary the present paper discusses the western and southern limits of the drift of the Illinois lobe as a single line, occupied at the Illinoian stage throughout its entire length by the ice lobe. Its extent may be seen by reference to PL VI. GEKERAL ASPECTS OF THE ILLINOIAN DRIFT SHEET. Extent of its exposures. — Tlic Illinoiau slieet is extensively exposed to view outside the lowan and Wisconsin sheets in Illinois and southwestern Indiana. In western and southei'n Illinois and in southwestern Indiana it constitutes the surface sheet (aside from a thin loess coating) over the entire interval between the glacial boundary and the outer moraine of the Wisconsin series. ' In a paper presented by the writer at the twelfth annual meeting of the Iowa Academy of Sciences: Proc. Iowa Acad. Sci., Vol. V, 1898, pp. 71-80; also Jour. Geol., Vol. VI, 1898, pp. 171-181. 26 ' THE ILLINOIS GLACIAL LOBE. The greatest width of this area is about 125 miles, and the width nowhere in western or southern IlUnois falls much below 75 miles. In southwestern Indiana it occupies a triangular-shaped area, broad at the west and naiTow at the east, for the glacial boundary passes northward neai'ly to the edge of the Wisconsin drift in the south-central portion of that State. In the portion of Illinois north from the latitude of Rock Island tlie lowan drift occupies a large part of the interval between the glacial bound- arj^ and the outer moraine of the Wisconsin series. A drift, tentatively- referred to the Illinoian, forms the surface sheet in that region in Stephen- son County and parts of Winnebago, Ogle, Whiteside, Carroll, and Jo Daviess counties. A small area of this earlier drift in southwestern Wis- consin is exposed outside the limits of the lowan, but the exact boundaries of the latter have not been determined. If the loess capping be disregarded, nearly two-thirds of the glaciated portion of Illinois has the Illinoian drift as a surface sheet. The remainder of the State is mainly occupied hj the Wisconsin drift sheet, the lowan being exposed only in parts of a few counties. Topographic expression. — Tlie grcatcr part of the Illinoian drift has a plane surface, destitute of the swells and ridges which usually occupy the Wis- consin till sheet. There are, however, a few belts of sharply ridged drift found Avithin its area, and the border is ridged throughout much of south- eastern Iowa and western Illinois. The most conspicuous ridging is found in a strip about 20 miles wide leading southwestward through the Kaskaskia Basin from the border of the Wisconsin drift in Shelby County across southeastern Christian, eastern and southern Montgomery, western Fayette, Bond, Clinton, southeastern Madison, eastern St. Clair, and eastern Ran- dolph eoimties. This strip embraces a series of nearly parallel ridges, which are discussed in some detail farther on as the ridg&d drift of the Kaskaskia Basin. Another ridged belt is found in eastern Sangamon and southwestern Loffan counties, and this is discussed below as the Buffalo Hart moraine, the village of Buffalo Hart being situated on it. A less conspicuous belt of ridged drift traverses southern and western Fulton County, touching eastern ]iIcDonough County near Bushnell, and apparently having its continuance into Knox and Peoria counties in a chain of mounds and short ridges. It has far less prominence than the two belts just mentioned, its relief being but GENERAL ASPECTS OF ILLINOIAaST DEIFT SHEET. 27 15 to 30 feet above the bordering plains, and the breadth of the main ridge one-half mile, more or less. In the northwestern part of Illinois, in Stephenson, Ogle, and Carroll counties, there are gravelly ridges, some of which are of esker type, and are discussed in detail below. Aside from the ridged belts just mentioned, there have been found only occasional knolls, either isolated or in small clusters, and these seldom rise 50 feet above the bordering plains. The knolls are more abundant in western Illinois than in southeastern Illinois and southwestern Indiana In the latter districts entire comities have been traversed without the discovery of a knoll so much as 10 feet in height. Thickness of the drift. — The Well records obtained in the region occupied by the Illinoian drift indicate that the average distance to rock on the preglacial or original uplands is not far from 50 feet. In this 50 feet is included the loess, which is several feet in depth, and possibly also pre-IUinoian drift. Along- original valleys the thickness is 100 to 200 feet or more. There are extensive areas in the northwestern counties of Illinois and in the comities bordering the Wabash River, both in Illinois and in Indiana, where the ridges carry scarcely any drift, while neighboring valleys may be tilled to a depth of 100 feet or more. In western and south-central Illinois the ridges usually carry 30 to 50 feet of drift, the general amount of drift being gi-eater than in northwestern Illinois or southeastern Illinois and southwestern Indiana. Throughout the area occupied by the Illinoian drift the main preglacial valleys are usually but partiallj^ concealed, though the small valleys and tributaries are often filled so completely that their position is revealed only by borings. In this resjiect the Illinoian drift is in striking contrast with the Wisconsin, for where that sheet is present the main valleys are as com- pletely concealed as the lesser ones. Records of a large number of wells which have been sunk in the Illinoian drift area are presented in the portion of this report dealing with the wells (Chapter XIV). Structure of the drift. — Tlirougliout tlie area occupied by the Illinoian drift till predominates, there being but a small amount of sand or gravel except in deeply tilled valleys. The ridges above mentioned are usually com- posed of till, though pockets or thin beds of sand or g-ravel have been discovered in some of them. Upon passing toward the glacial boundaiy 28 THE ILLINOIS GLACIAL LOBE. the drift becomes more variable in its constitution than at points remote from the boundary. This variableness is set forth in the detaikd discussion of the drift border below. The till whicli forms this lllinoian sheet is usually of a yellowish-brown color to a depth of 15 feet or more, beneath whicli it assumes a gray or blue-gray color. In many places there is a transition from the brown to the gray, in which gray streaks remain in the brown till, or cracks stained a brown color extend down some distance into the gray till. In such places it is probable that the brown is simply an altered gray till, the oxidation of the iron having produced the change in color. In places a thin bed of sand or gravel occurs at the junction of the brown and gray till, which gives them the appearance of being originally distinct. But it is not certain that the brown till in such places was not originally gray in color. The points at which there is a transition from till of one color to that of the other are so numerous that it seems highly probable that the brown till is generally but an altered phase of the gray. At least nothing decisive has been discovered to indicate that the brown and gray tills are referable to distinct invasions or to different modes of deposition by the ica In portions of central Illinois, especially in the Sangamon and Kaskaskia and Embarras drainage basins, the well diggers and di'illers report a marked change in the texture of the drift in passing from the brown to the gray ■tills. The gray till is said to be much harder to penetrate than the broM'u. Where wells are dug, they may be spaded without difficulty through the brown till, while in the gray till a pick is usually required to remove the material. This difference may be due to the effect of ground water or to some secondary change in the brown till which does not affect the underly- ing gra}^ till, a change which is coextensive with the change in color. It may, however, prove to be an original difference and may be of significance in determining the glacial history. Possibly the gray till in these districts is sufficiently older than the overlying brown till, or sufficiently distinct from it in deposition, to be referred to a separate stage and c'(iusidered pre-Illi- noian. But few exposures of this hard till were found, and in these no sign of a distinct interval between tlie bro^vn and the gray tills was recognized. The available evidence is, therefore, of an inconclusive nature. Gumbo (?i. — The lllinoian till sheet, and also portions of the Kansan till sheet in southeastern Iowa and northern Missouri, ai-e extensively covered GENERAL ASPECTS OF ILLINOIAN DEIFT SHEET. 29 with a gummy or very adhesive clay, often several feet in depth. This clay is found at frequent intervals throughout the entire area in which the Illinoian sheet is exposed to view outside the limits of later till sheets, and has also been found under the later till sheets at some distance back from their margin in the central portion of Illinois. It occurs as far west as the writer has made examinations in Iowa, a distance of 50 miles or more beyond the limits of the Illinoian till sheet, and is known to be present over extensive areas in northern Missouri. Its extent and im- portance seem to have been unrecognized prior to the present survey. It is not such a continuous deposit as the overlying loess, there being- many places Avhere the loess rests directly upon typical till. It is most conspicu- ous in the vicinity of the Mississippi Valley and in the southern portion of Illinois as far south as the glacial boundary. The region in which it occurs ranges in elevation from 400 feet up to fully 800 feet above tide. Possibly much higher elevations are attained by it in passing westward from the Mississippi. Like the loess, it seems to be independent of contour lines in its distribution. The color of this clay varies from ash or light gray to nearly black. The black portions are heavily charged with liumus and in places present the appearance of a swamp muck. It is in this clay that the black soil so often seen at the base of the loess is usually developed. Where the loess rests directly upon till the soil formed beneath it is usually of a reddish- brown color. This gummy clay contains a few small pebbles. They seldom exceed a half inch in diameter and are far less numerous than in the typical till. It often bears a striking resemblance to the "gumbo" of the Illinois and Mississippi River flood plains, which is deposited by flooded streams in the portions of the flood plains where there is but little current. It, however, contains more and larger pebbles than the gumbo of these flood plains. The origin of this deposit," and its time relations compared with the overlying loess and the underlying till, are questions of prime importance, but as yet no satisfactory conclusions have been reached. There is much in the appearance of the deposit to support the hypothesis of aqueous deposition. The pebbles may, perhaps, have been derived from neighbor- ing prominent points in the till during the progress of a submergence. The action of floating ice may be postulated as an accompaniment of submergence 30 THE ILLINOIS GLACIAL LOBE. ■whether the water be shallow or deep, and this may have caiTied stones in sufficient number to have supplied the clay with the iew pebbles that it contains. The difficulties arising- from the great range in altitude which the deposit presents may not be fatal to the hypothesis of submergence. The hypothesis is, therefore, still entertained, especially since none more satisfactory has suggested itself, but it can not be confidently put forward as a solution. In considering the time relations of this clay, there is decisive evidence that it was deposited at a much later date than the Kansan sheet, in the fact that it also overlies the Illinoian, a younger sheet of drift. The evidence is equal!}' conclusive from its relation to terraces cut in the Kansan. The gummy clay, as well as its coating of loess, is found on ten-aces bordering valleys cut in the Kansan sheet, and also on the uplands occupied by that sheet. All the main valleys examined in southeastern Iowa had been cut to a depth of 50 feet or more into the Kansan sheet, and often to a width of 1 or 2 miles, prior to the deposition of this clay. If, therefore, it had been examined onl}- in districts outside the limits of the Illinoian, it might have been demonstrated to be a much younger deposit than the Kansan. Passing to the Illinoian sheet, it is found that the changes effected in its surface prior to the deposition of the cla}- under discussion are less than in the Kansan, yet some change was apparently effected in its surface. In fact, the surface of the till has often the appearance of marked atmospheric reddening prior to the deposition of the gummy clay, and there is usually iin abrupt chaiige from gummy clay to the till. The till is also not infre- quently leached of its calcareous material for several feet below the base of the gummy clay. In places the gummy clay is mingled with the luider- lying till, but it does not follow that the two deposits are contemporaneous. The Illinoian till sheet was not so conspicuously channeled by streams prior to tlie loess deposition as the neighboring portion of the Kansan, but the slight channeling which took place seems to have antedated the deposi- tion of the gummy clay as well as that of the ove^'lying loess. This clay is apparently more conspicuously developed in small channels cut in the Illinoian than on the bottosns or terraces of the broad channels. Not infre- (|uently these small channels are so greatly filled by the clay that the surface is nearly restored to its original pl^ineuess. The writer has found GENERAL ASPECTS OF TLLmOIAN DRIFT SHEET. 31 numerous exposures where such filhng- reaches a depth of 15 or 20 feet in districts where the general thickness of the gummy clay is scarcely 5 feet. The presence of so many exposures where there is evidence of an interval between the deposition of the till and tliat of the clay under discussion has led the writer to conclude that in the exposures where the two deposits appear to be blended there has been redeposition of the till in connection with the later deposit. In so commingled a sheet as till it is a very difficult matter to determine whether redeposition has occurred since the withdrawal of the ice sheet. In view of all the data now available the conclusion seems warranted that this clay is somewhat younger than the Illinoian. No suitable name has as yet been found for the clay, although the name gumbo has been applied to it by residents of the region which it char- acterizes, becaiise of its gummy character. This name is open to objec- tion for the reason that it has already been applied to other deposits of different age and different origin. There is a gumbo in the Cretaceous series of the Western plains. The term is also applied to the flood-plain deposits of the Illinois and Mississippi, which are still in process ot accumu- lation. The name gumbo has, however, been used b}'' McGree in his discus- sion of a compact phase of the loess found in southeastern Iowa and northern Missouri, and of a dark clay at its base, apparently the clay under discussion. It is his opinion that the loess there owes its compactness to derivation from the clay beneath it.^ Until the origin and time relations are more satisfactorily determined, it may be as well to leave unsettled the name for the deposit. It remains to consider the probable time relations between the clay under discussion and the sheet of loess that overlies it. The gummy clay, as noted above, has usually a blackened surface due to humus, a feature which indicates that it was exposed to conditions favorable to plant growth. The plant remains in this clay are seldom sufficiently well preserved to admit of identification. The writer. howeA'er, found bits of wood in an exposui'e along the Santa Fe Railway near New Boston, in Lee County, Iowa, which have been identified by Mr. F. H. Knowlton, of the United States National Museum, as a species of conifer. The specimens were too small and not sufficiently well preserved to enable him to determine the genus and species, though they appear to belong to the genus Picea (spruce). 'Eleventh Aun. Kept. U. S. Geol. Survey (for 1889-90), 1891, pp. 299, 414, 461-471, 508-51U. 32 THE ILLINOIS GLACIAL LOBE. They consist of rootlets about 2 cm. in length and 2 mm. in diameter. They are, therefore, too small to afford good sections of the wood cells. The locality where these specimens were obtained is now a prairie region and the spruce tree is not native in the forests which border the streams, the only conifer present being the red cedar. Several instances of the occurrence of logs at the base of the loess in western Illinois have been reported to the writer by well drillers, but no specimens have been obtained. The evidence is, however, considered good that much of this region was forest-covered prior to the deposition of the loess. Whether this emergence and forest growth occupied a long period has not been satisfactorily deter- mined. . Last season (1897) the writer found a fine exposure of muck and peat and wood, associated with silt, at the base of the loess in a cutting on the Toledo, Peoria and Western Railway, 4 miles west of Washington, Illinois, a photograph of which is presented in PI. XI, B. It is several miles inside the border of the Wisconsin drift, and the loess is here covered by a bed of till of Wiscoiisin age. At this cutting the Wisconsin drift is only 15 feet in thickness, the upper portion having been removed by erosion. The section at the cutting is as follows: Section at a cutting on the Toledo, Peoria and Western Railway, 4 miles west of Wash- ington, Illinois. Feet. Gravel 6 Blue till ( Wisconsin) 8 Gray clay, laminated, pebbleless, very calcareous 1 Brown loess, probably of lowan age, calcareous, and containing helix shells 6 Pea^y silt of brownish black color, containing a large amount of wood (Sangamon) 5 Drab colored loess-liku silt, becoming brown toward bottom, filled with mats of librous roots. . 1-5 Reddish-brown leached till (IlUnoian) 4 Brown nnleached till (Illinoian) exposed 8 Total 42 Specimens of the shells in the loess, of the wood in the peat, and of the roots tinder the peat have been collected, but have not been specifically identified. The silt under the peat is somewhat similar to the deposit which overlies it, thougli it may prove to be of different origin. This series of beds seems to indicate that a land surface, which had been exposed to atmospheric action favorable for leaching of the till, was transformed into a swamp favorable to tlie growth of peat, and that this swampy condition was followed by the deposition of the loess. As the gummy clay just dis- GENERAL ASPECTS OF ILLINOIAN DRIFT SHEET. 33 cussed is not represented in this section, the question naturally ai'ises whether the silty material under the peat is not its equivalent. The question can scarcely be decided from such fragmentary evidence as is now available. This section appears to bring- the loess into closer relation to the gummy clay than had heretofore been supposed. If the blackened, humus-stained surface of the gummy clay required but a few centui'ies for its development, it would seem not unlikely that the deposition of this gummy clay and tliat of the loess are to be referred to the same epoch of low altitude, an epoch attended by more or less complete submergence, with interruptions or partial emergence of the land. The reddened and leached surface of the lUinoian till apparently signifies a long exposure to atmospheric action. The balance of evidence seems to favor a closer connection between the loess and the gummy clay than between the latter and the underlying lUinoian till. As the loess is discussed in some detail in connection with the lowan drift sheet, with which it is correlated, only a general statement concerning' it is made at this point. The entire surface of the Illinoian drift sheet appears to have received a capping of loess or loess-like silt at about the time of the lowan ice invasion, the deposit being found midway between the principal streams as well as along their borders, where it was first recognized. It is much thicker on the borders of the Illinois and Missis- sippi than on the divide between these streams or in the region east from the Illinois. In much of southern Illinois the thickness is only 3 to 5 feet, and the average thickness in districts east of the Illinois and Mississippi is probably less than 10 feet. On the borders of these streams its thickness is frequently 30 to 50 feet, though a portion of the valley border near the corners of Iowa, Missouri, and Illinois is characterized by a thinner coating of loess than is found to the north or south, the average thickness being scarcely 10 feet. Aside from its thickening on the borders of the Illinois and Mississippi, there is also a thickening- on the borders of the lowan drift sheet in Carroll, Whiteside, Henry, and Bureau counties, as indicated in the discussion of that drift sheet. Sections of the Illinoian drift. — For scctlous iUustratiug' thc structurc of the Illinoian drift sheet, reference may be made to the portion of this report devoted to the wells of Illinois (Chapter XIV). The well sections are taken up by counties, but attention is called to the several drift sheets which are MON XXXVIII 3 34 THE ILLINOIS GLACIAL LOBE. penetrated by the wells in the various counties of the State. The structure of the portion of the Illinoian drift in southeastern Iowa and western Illinois is set forth in the detailed discussion of the border of the Illinoian drift sheet which follows. THE DRIFT BORDER. DISTRIBUTION. The border of an old drift sheet, tentatively referred to the Illinoian, emerges from beneath the Wisconsin di'ift in southern Wisconsin a few miles southwest of the city of Madison, and from that point southward to the Mississippi River it forms the eastern border of the Driftless Area of southwestern Wisconsin and northwestern Illinois. The border of this drift sheet probably crosses the Mississippi a few miles below Savanna, but, as shown in Pis. VI and XII, the presence of the lowan drift sheet, together with the heavy loess deposit, both of which are later than this drift, has so obscured it that its limits can not well be determined in Clinton and Scott counties, Iowa. In Muscatine County, Iowa, the slightly ridged west- ern border of the Illinoian drift sheet becomes visible, and is distinctly devel- oped from that county southward. It crosses the Iowa River just below Columbus Junction and leads southward through western Louisa County, the village of Cairo being within a mile and the village of Morning Sun within 3 or 4 miles east of the border. It passes thence in a course west of south across northwestern Des Moines County and southeastern Henry County, tlie villages of Yarmouth and New London being situated on the ridged border and the village of Lowell, in Skunk River Valley, being situated where the border crosses that valley. In Lee County, as shown in fig. 4, the course of the ridge is southward past the village of West Point to the vicinity of the Mississippi bluff, about 5 miles below Fort Madison. From this point south- ward to Keokuk the border apparently is nearly coincident with the course of the Mississippi River, though there may be slight deposits of the Illinoian drift on the west side of the valley. Immediately south of Keokuk, on the Illinois side of the river, a distinct ridge of drift appears which marks the border; and this may be traced southward along the east bluff of the Mis- sissippi across Hancock and Adams counties, though in the southern portion of Adams County it lies back a mile or two east from the river bluft'. In Pike County the border bears gradually away from the Mississijjpl bluff in THE DRIFT BOEDER. 35 a southeastward course and comes to the Illinois River in the southeast part ot" the county; thence it follows the Illinois Valley southward to the mouth of the river, perhaps touching the west bluff in southern Calhoun County. The border then either follows the Mississippi bluff eastward past Alton, or continues southward across the projecting point of Missouri which borders the mouth of the Missouri River just above St. Louis. It is somewhat uncertain whether the drift found on the Missouri side of the Mississippi is of direct glacial deposition or a deposit made by streams; the greater part of it is assorted material. The presence of drift on the Missouri side of the Mississippi has been noted only in the district north from the citv of St. Louis. Below that city the drift border apparently follows the line of the valley of the Mississippi closely as far down as southern Jackson County. The Mississippi River there turns southward, but the drift border passes eastward, following the north slope of the elevated ridge which crosses south- ern Illinois and entering Indiana in the extreme southwest corner of that State. The drift border, as indicated on PI. VIII, crosses the southwestern county of Indiana (Posey) in a northeastward course lying near the valley of the north fork of Big Creek. It cuts across the nort,hwest corner of Vanderburg County and enters Gibson County in sec. 16, T. 4 S., R. 11 W. Thence it passes northeastward, touching the village of Haubstadt and coming to Pigeon Creek in sec. 22, T. 3 S., R. 10 W., at the junction of Sand Fork and i\Iuddy Fork. From this creek the course for a few miles is northward to the divide between Pigeon Creek and Patoka River, which it crosses about 4 miles east of Princeton. It there swings eastward and comes to Patoka River near the line of sees. 32 and 33, T. 1 S., R. 9 W. It enters Pike County about 1 mile south of Oatsville, in sec. 27, T. 1 S., R. 9 W. In that county it lies but a short distance north of Patoka River, and apparently follows nearly the divide between the small northern tributa- ries and Flat Creek, a large northern tributary, to the mouth of Flat Creek in western Dubois County. From this point eastward to the vicinity of Jasper, and thence northward to East White River, there is a sand-covered plain in which the boundary is difficult to locate. Possibly this plain was covered by the ice sheet, since glacial pebbles several inches in diameter are found beneath the sand on its east border. The sand seems to have been deposited in a small glacial lake, Lake Patoka, which occupied this 36 THE ILLINOIS GLACIAL LOBE. plain and neighboring sections of the Patoka Valley while the ])resent out- lets along the White and Wabash rivers were blocked by the ice sheet. For a few miles north from East White River the exact position of the glacial boundary is difficult to locate, for only scattering pebbles are foiuid along the border. It seems, however, to pass near the village of Alfords- ville, in Daviess County, and thence to take a northeastward course to the Ijluff of East White River near Whitfield, in Martin County. The border follows the west blufiP of East White River northward past Mount Pleasant to the bend near that village, from Avhich point it continues northward, passing about a mile east of the village of Loogootee. The border then bears west of north and soon enters the western range of sections in I\Iartin County and lies very near the Martin-Daviess county line for 10 or 12 miles. It makes a slight protrusion eastward at the valley of Furse Creek, in northwestern Martin County, and enters Greene Count}^ about a mile south- east of the village of Scotland. The course of the glacial boundary through Greene, Owen, and Mon- roe counties has been mapped in detail by Mr. C. E. Siebenthal, of the Indiana Geological Survey, and is represented in PI. IX. From near Scotland it has a course slightly east of north to the valley of Plummer's Creek, in sec. 9, T. 6 N., R. 4 W. North of this creek it makes an east- ward protrusion of about 2 miles into a lowland tract known as the Ameri- can Bottom, reaching sec. 36, T. 7 N., R. 4 W. North of this lowland the course of the boundary is west of north to the valley of Richland Creek, in sec. 9, T. 7 N., R. 4 W. It follows the east bluff for about 3 miles and crosses to the west side of the creek in sec. 35, T. 8 N., R. 4 W. It follows nearly the west bluff to sec. 17, T. 8 N., R. 3 W., passing about a mile southeast of the village of Newark. The boundary makes an eastward protrusion of about a mile into Richland Creek Valley in sec. 16, from which the course is northward into Owen County. Entering Owen County in sec. 33, T. 9 N., R. 3 W., the boundary leads northeastward past Free- man post-office and crosses into Monroe County in sec. 6, T. i) N., R. 2 W. The course continues northeastward through northern Monroe County, the boundary being about 2 miles north of Ellettsville and 1 mile north of Modesto, and coinciding nearly with Indian Creek Valley from mouth to source. From the head waters of Indian Creek, in sec. 3, T. 10 N., R. 1 W., the boundary leads eastward about 6 miles, near the Monroe-Morgan THE DRIFT BOEDER. 37 county line, and. there reaches its most northern point in Indiana. It is here that the hmits of the portion of the ice sheet properly included, in the Illinois glacial lobe should be placed. The boundary from there leads southeastward to the Ohio Vallej^, and is discussed in another report in preparation. The drift border shows no evidence of an overlapping at this reentrant angle of one lobe upon territory abandoned by the other, such as was noted on the west side of the Illinois lobe. The border south- east from the reentrant seems to be a direct continuation of that just traced. The length of the drift border thus outlined is about 700 miles, and the width of the lobe encircled by it is about 300 miles. The tracing of this border has been the product of several independent surveys. The portion in Wisconsin was largely determined by members of the Wisconsin Geo- logical Survey. The border in northwestern Illinois was partly determined by members of the Illinois Greological Survey, and subsequently with greater approximation by Prof. R. D. Salisbury, of the United States Greological Survey, but the precise limits have not as yet been mapped. The portion in Iowa, and also the portion from the southern edge of Iowa southward to the vicinity of St. Louis, have been traced by tlio present writer. Salis- bury, however, made observations at an earlier date on the limits of the drift in Pike and Calhoun counties, Illinois, and discovered evidence suo-- gesting that a portion of these counties is unglaciated. The deposits of drift on the Missouri side of the Mississippi, in the vicinity of St. Louis, were first described by Prof A. H. Worthen^ and later by Profs. G. F. Wright,' J. E. Todd,^ and H. A. Wheeler.* The portion of the boundary from St. Louis southward to Jackson County, Illinois, was mapped by Prof G. F. Wright and discussed in Bulletin 58 of this Survey. Wright also mapped the boundary across southern Illinois, but this had previously been outlined with a fair degree of approximation bj- Worthen.^ Wright also made a tracing of the glacial boundary in southwestern Indiana, which was published in Bulletin 58 of this Survey. But the posi- tion of the boundary in that region is found to be shown very inaccurately, the limits of the drift being from 5 to 20 miles outside the hmits placed by ' Geol. of Illinois, Vol. 1, 1866, p. 314. 2 Bull. U. S. Geol. Survey, No. 58, pp. 72-73. = Bull. Geol. Soc. America, Vol. V, 1894, p. 539. Missouri Geol. Survey, Vol. X, 1896, pp. 161-163. ^ Trans. St. Louis Acad. Sci., Vol. VII, No. 3, Feb., 1895. ^Geol. of Illinois, Vol. 1, 1866, p. 27. 38 THE ILLmOIS GLACIAL LOBE. Wright. As indicated above, its position in Monroe, Owen, and Greene counties lias been mapped in detail by Mr. C. E. Siebenthal, of the Indiana Survev. The portion l^etween Greene County and the southwest corner of Indiana has been traced by the present writer. The portion mapped by Siebenthal has been reconnoitpred by the present writer, and also most of the border in southern and southwestern Illinois. TOPOGRAPHIC EXPRESSION. The drift border in the portion examined by the writer, both in south- eastern Iowa and in western Illinois, is generalh* marked b}^ a low ridge, seldom rising more than 60 feet above the outer border disti-ict, and averaging perhaps 40 feet. In Adams and Pike counties there are a series of ridges shown on the glacial map (PI. VI), which have neai-ly parallel trend, but which are broken by wide gaps, and represent imperfectly the successive positions of the ice margin in these counties. The ridge forming the border seldom exceeds 2 miles, and is usually but a mile or less in width. On the eastern slope there are low swells, 10 to 20 feet in height, extend- ing out in places to a distance of several miles from the drift border, but seldom showing a disposition to form connected chains or ridges. The portion of the drift border along the east side of the Driftless Ai-ea in northern Illinois and southern Wisconsin is in places slightly thick- ened beyond the usual depth of di'ift in districts to the east, but is in other places very thin. It may be possible to trace an ill-defined ridging more or less successfully near this border. The writer's observations touch it at only a few points, and are not sufficiently full or continuous to justify an opinion on this matter. From the point where the border crosses the Illinois River in south- eastern Pike County, Illinois, southward to the Mississippi, there are occa- sional knolls, 20 to 40 and occasionally 60 feet in height, the majorit}' of whicli are elliptical, with tlie longer axis trending ENE.-WSW., or about at right angles to the trend of the drift border. These knolls do not lie at the extreme border, but are situated 5 to 10 miles or more liack from it. Their form is drumlinoid, but seldom assumes the regularity of the typical drumlin. The portion of the drift border touching the State of Missoui-i displays (ihIa- ]);itchy deposits of drift, usually in t]\v valleys or depressions, and TOPOGRAPHIC EXPEESSION OF THE DRIFT BORDER. 39 seldom, if ever, aggregated in the form of knolls or ridges. As noted above, it is not certain but that the deposition was largely made by streams, rather than by direct glacial action. Below St. Louis there is a less regular and lighter deposit of drift in the vicinity of the border than in districts to the north, and the border there, so far as noted, is without topographic expression, the drift being found largely in depressions, with only a thin veneering on the hills. As noted farther on, a prominent belt of drift ridges comes down nearly to the di-ift border from the northeast across southeastern Madison, central St. Clair, eastern Monroe, and northern Randolph counties, and there turns southeast- ward, taking a course nearly parallel with the drift border and scarcely 10 miles back from it. Upon turning southeastward this belt of ridged drift becomes ill-defined, but has been traced with some certainty to central Jackson County (midway between Ava and Murphysboro). As yet no line of ridges marking a continuation has been found farther southeast. It is possible that the sheet of drift which terminates at this belt of ridges may come to the glacial boundary in southern Illinois, and constitute that boundary from there eastward. In southern Illinois occasional low knolls, 20 feet or less in height, occur in the vicinity of the drift border, and there appears to be a slight ridging in east-west direction in the southern portion of Williamson County, a ridging sufficient to influence the course of streams, as indicated on a later page (p. 527). In the vicinity of the Wabash River, near Ridgway, and thence noi'theastward to New Haven, Illinois, there is a belt of low sandy knolls and ridges, the origin of which is not clearly determined. Possibly they are entirely the result of wind action, or they may be due in part to glacial action. In southwestern Indiana a few places were found where the drift border and districts immediately back of it show a tendency to aggregation in low knolls and ridges. Perhaps the most conspicuous instance is found in Gibson County, near Fort Branch, where for a distance of about 3 miles along the east side of the Evansville and Terre Haute Railway there is a ridge of drift 30 to 50 feet in height and nearly a mile in breadth, whose surface is quite undulatory. From the southern end of this ridge south- westward into Posey County knolls 10 to 20 feet in height are of frequent occurrence, and in places become so closely aggregated as to give a 40 THE ILLINOIS GLACIAL LOBE. decidedly movainic expression to the drift surface. Occasional knolls and low ridges of di-ift were found in northeastern Gibson and northern Pike counties, Indiana, lying usually within 5 miles of the glacial boundarj^ No knolls or ridges of drift were noted in the district north of East White River, nor have any been observed far back from the glacial boundary in southwestern Indiana and southei'n Illinois. Reviewing the above statements, it appears that the border is only in places marked by a definite ridge, and tliat there the ridge has mild expres- sion and slight dimensions compared with the expression and dimensions of the bulky moraines formed at the Wisconsin stage of glaciation. The expression is also much milder than that of ridges formed at some distance back from the drift border in southwestern Illinois, which pertain to the Illiuoian sheet, descriptions of which are given below. STRUCTURE OF THE DRIFT BORDER. The drift border, as here discussed, includes a belt several miles in width, embracing a sufficient amount of territory to afford a fair index of the variations which are displayed in the immediate vicinity of the border. The discussion begins in Lee County, Iowa, which is the writer's native county, since the sections of wells and also natural exposures have been studied more thoroughly there than at an}' other part of the di'ift border. This county is situated in the extreme southeast corner of Iowa. (See fig. 4). During the drought of 1894 and 1895 a large number of new wells were sunk, and the writer had opportunity to make many observations concerning the character of the drift penetrated by them. The Illiuoian drift sheet is found to be generally but 10 to 30 feet in thickness, though on the ridge which forms its western limit the thickness is increased to 50 feet or more. In several of the wells wliich were observed during excavation the Illiuoian drift is composed of a brownish, pebbly clay, which has been so thoroughly leached that no response with acid could be obtained, even where the thick- ness is 20 feet. But in some of the wells this sheet contains a very cal- careous till which has beeii leached only to a depth of 6 or 8 feet. This variability in the amount of leaching is thought to be due to difference in the derivation of the material. That which is leached from top to bottom is probably made up in large part of the surface portion of the older sheet of drift which is here overridden. That which is a typical calcareous till STEUCTUEE OF THE DEIFT BOEDEE. 41 was probably in part formed by the ice in passing over rock ledges and in part collected from the calcareous portions of the underlying sheet. It does not seem at all probable that the variations in the depth of the leached material are due entirely to leaching which has occurred since the Illinoian sheet was deposited. The portions which are leached to great depth seem to be no more readily pervious to water than those in which the leaching has extended to a depth of only 6 or 8 feet. The ridge marking the western limits of the Illinoian diift, in Lee County, is in places thickly set with bowlders, but as a rule it appears to carry no more bowlders than the portion of the same sheet in the plain tracts immediately east. T'he bowlders and smaller rock constituents of the Illinoian drift are found to diifer somewhat from those of the sheet that underlies it, there being- certain rocks found in it that are not found in the underlying sheet, while other rocks differ in abundance in the two sheets. Several bowlders of red jaspery conglomerate, apparently from the Huronian outcrops north from Georgian Bay, have been found in this county on and east of the ridge that marks the Avestern limits of the Illinoian drift, and these are thought to point decisively to the Labradorian invasion. There are also quartzite rocks present in the Illinoian drift that have not been seen in the sheet beneath it and which probably were derived from sources not far distant from the Huronian that bears the jaspery conglomerate. The cherty beds of the Burlington limestone that outcrop along the Mississippi and its tributaries have been incorporated in the Illinoian di'ift sheet and transported westward to the extreme limits of that sheet. They point with certainty to the influence of the Labradorian invasion. The Illinoian till sheet in Lee County, as also in counties to the north, is separated from the underlying Kansan till sheet by a weathered zone accompanied by beds of black muck and peaty material. This was first brought to the writer's notice about ten years ago, in a well sunk near the village of Yarmouth, in Des Moines County. For this reason, and because it is not liable to be a source of confusion by duplication in other parts of the g'laciated region, the name Yarmouth has been proposed to cover the interglacial interval between the Kansan and Illinoian.-' The village of ' The -vreathered zone (YarmoutU) between the Kansan and Illinoian till sheets, by Frank Leverett: Proc. Iowa Acad. Sci., Vol. V, iip. 81-86, 1898; Jour. Geol., Vol. VI, 1898, pp. 238-243. 42 THE ILLINOIS GLACIAL LOBE. Yarmouth is situated about 20 miles northwest of Burlington, the county- seat of Des Moines County, on the line of the Burlington and Western Railway. It stands on the ridge which marks the western border of the Illinoian till sheet. The well above refeiTed to, which first suggested to the writer the occurrence of two distinct sheets of till in southeastern Iowa, was made by William Stelter, on the border of the village of Yaraiouth. The writer A-isited the well soon after it was bored and made out the follow- ing section fi-om the material exposed in the dump : Section from well of William Stelter, near Yarmouth, Des Moines County, Iowa. Feet. Soil and loam (lowan loess) 4 Brownish yellow till (Illinoian) 20 Gray till (Illinoian) 10 Peat bed with twigs and bones (Yarmouth) 15 Gray or ashy sandy clay, containing wood (Yarmouth) 12 Fine sand (Yarmouth).... 16 Yellow sandy till with few pebbles (Kansan) 33 Total depth - 110 The bones found in the peat were sent to the Smithsonian Institution and there identified by Dr. F. W. True, as follows: (1) A portion of the pelvis and the upper part of the femur of the wood rabbit {Lepws sylvaticus); (2) the scapula of the common skunk (jSIepliiticus mephitica). The occurrence of these bones was first announced by McGee, in the Eleventh Annual Report of this Survey, and referred to a "forest bed," but without more definite reference.^ The thickness of the peat in this well and of the associated sand}- clay charged with wood, is an impressive evidence of an interglacial interval of considerable length. But in the writer's opinion it furnishes less weighty evidence than is afibrded by the general weathering which took place on the surface of the Kansan sheet prior to the deposition of the Illinoian di-ift. The peat naturally aiTests attention quicker than the reddened zone, but is more restricted in its development; yet several instances of the occurrence of beds such as the one at Yarmouth have been brought to the writer's notice. They appear to be rather more prevalent along the extreme border of the Illinoian than at points some miles back beneath it ; but instances occur all over the portion of southeastern Iowa invaded by the Illinois lobe. ' See p. 495 of report cited, published in 1891. / STRUCTURE OF THE DRIFT BORDER. 43 The peaty dej)osits are usually found associated with sandy beds, while the soil and weathered zone cap a sheet of till or stiff clay. In many of the wells in southeastern Iowa, and also in natural expo- sures, a reddened or deeply oxidized clay is found, instead of peat or muck, between the Illinoian and Kansan sheets. This constitutes usually the weathered surface of the Kansan, and appears to have been originally a calcareous till, like the remainder of that deposit. Acid tests have fre- quently been made in freshly dug wells and in natural exposures with a view to determine the amount of leaching prior to the deposition of the Illinoian till sheet. It is found that, as a rule, no response to acid is obtained at less than 4 feet, and often the response does not set in within 6 feet of the top of the buried Kansan sheet. In the cases where leaching occurs within 4 feet of the surface, it seems safe to infer that a portion of the leached material liad been removed prior to the deposition of the Illinoian till sheet. While the leached material usually bears a striking resemblance to the underlying calcareous till, exposures have been found in which it differs in general appearance and is perhaps a deposit of different origin. These deposits also are thoroughly leached at surface. This weathered zone is so conspicuous throughout the region of overlap of the Illinoian upon the Kan- san that the writer has satisfied himself of the occurrence of a long interval of deglaciatioia prior to the deposition of the Illinoian drift. Instances of the occurrence of this weathered zone, and also evidences of erosion between the Kansan and Illinoian glaciations, are presented below. With this brief explanation of the drift border in the part most familiar to the writer the discussion will pass to the north part of the border in southern Wisconsin, and proceed thence southward. From the descriptions of the drift in southern Wisconsin, presented in the Greology of Wisconsin and in Chamberlin and Salisbury's paper in the Sixth Annual Report of this Survey, it appears that the drift border is characterized by occasional gravelly knolls and ridges, some of which are of distinct esker type. There are also gravel and sand deposits on plane- surfaced tracts, but the greater portion of the drift appears to be a moderately stony till Avith an adhesive clayey matrix. This phase of the drift border continues southward across northwestern Illinois. It is found that some of the preglacial valleys near the drift border were filled with a deposit of fine silt or clay containing very few pebbles. These deposits characterize 44 THE ILLINOIS GLACIAL LOBE. ^^alleys which had eastward drainage in preglacial times and are probably to be attributed to the ponded waters held in front of the ice and laden with laro-e amounts of fine sediment carried by the waters issuing from the ice. Portions of the border in northwestern Stephenson, southeastern Jo Daviess, and northwestern Carroll counties are liberally strewn with bowl- ders of granite and other distantly derived rocks. The number appears to be greater within the first 5 miles back from the drift border than at more remote points. In this portion of the drift border the loess coating is thin except in the immediate vicinity of the Mississippi Valley, its average depth being scarcely more than 5 feet. On slopes it is largely removed, leaving the surface of the glacial drift exposed to view. The interval between the southern point of the Driftless Area near Savanna and the northernmost point at which the Illinoian drift border is recognized on the Iowa side of the Mississippi is about 50 miles. A direct line across it traverses a low plain covered with a very bowldery sheet of lowan drift, described by McGee, which is nearly free from deposits of loess in the middle portion, but which is bordered in the peripheral portion on the north east and south by loess-covered drift. No recognition of the Illinoian drift has been made in this interval along the direct line of con- nection. But it has been identified in Davenport and at points west of that city in Scott and eastern Muscatine counties, Iowa. It is therefore certain that the Illinois lobe extended beyond the Mississippi River at least as far north as eastern Scott County. Prof J. A. Udden has recently published an important table showing- notable differences in, the rock constituents of the lUinoian and the under- lying drift sheets of Muscatine County, from which it appears tliat the constituents of the Illinoian are largely derived from outcrops to the east.^ Exposures of drift in Davenport and Muscatine, Iowa, were made the subject of joint investigation by Prof Samuel Calvin and Dr. H. Foster Bain, of the Iowa Ceological Survey, Prof J. A. Udden, and the writer, in November, 1897, and there was entire unanimity in the interpretations. At Davenport the first exposure examined was one previously described by McGee,- which is situated at the northwest corner of Sixth and Harrison ' Iowa. Geol. Survey, Vol. IX, 1S99, p. 330. 2 Eleventh Ann. Kept. U. S. Geol. Survey (for 1889-90), 1891, p. 491; also tig. 77. STEUCTUEB OF THE DRIFT BORDER. 45 streets. The occurrence of a distinct soil and weathered zone between the loess and the upj^er or Illinoian till sheet is a feature not noted by McGee; with this exception his description applies well to the exposure. The section, as determiijed November, 1897, is as follows: Section of drift at corner of Sixth mid Harrison streets, Davenport, loica. Feet. lowan loess', partly eroded 8 Black soil 1 foot, with Illiuoian till surface leached and reddened to a depth of 3 feet in theSan- gamou interglacial stage; total 4 Brown calcareous till, with a few calcareous nodules ; traces of horizontal bedding near bottom, but with few vertical fissures or seams, a characteristic Illinoian till 7 Brown till, calcareous, with numerous vertical fissures and seams, and occasional horizontal sand partings, with tendency to break in cubical blocks, a characteristic oxidized Kansan till . 8-10 Blue-gray till, calcareous, with occasional horizontal saud partings and numerous vertical seams, also tendency to break in cubical blocks; bowlder-like masses of gravelly sand often 2 or 3 feet in diameter, in some cases showing crumpling of beds, occur in the lower part of the exposure; a characteristic unoxidized Kansan till; entire depth 35-40 Fine sand, appearing only on Harrison street, at base of exposure 3 Total, about , 70 The base of this exposure stands about 50 feet above the level of the Mississippi River, while the top of the exposure is nearly at the level of the uplands. In this exposure no leached zone appears at the junction of the Illinoian and Kansan, probably because of removal by the Illinois ice lobe. ' The change in physical character upon passing- from the brown till of the Illinoian to that of the Kansan is very striking. The Illinoian may be denoted a friable or crumbling till, while the Kansan is a caking till where characteristically developed. The next exposure examined presented a weathered zone and evidence of erosion between the Illinoian and Kansan, and also showed the lowan loess in its full thickness. It is found along Eighth street in a steep descent between Myrtle and A'^ine, and is as follows: Section of drift along Eighth street, beticeen Myrtle and Vine streets, Davenport, Iowa. Feet. lowan loess 80 Reddish-brown surface of Illinoian till sheet, leached and stained durihg Sangamon inter- glacial stage 2i to 3 Brown calcareous till, crumbling readily ; a characteristic Illinoian till 15 Ash-colored gummy clay with black streaks, apparently of humus, representing the Yarmouth interglacial stage 2 to 3 Brown till, calcareous, fracturing in cubical blocks, color changing to grayish blue at 12 to 15 feet ; characteristic Kansan till 25 Total, about 1^ 46 THE ILLINOIS GLACIAL LOBE. The surface of the Kausau apj^ears to have been subjected to some erosiou, for it drops down about 15 feet iu a distance of 20 rods in passing toward the river valley. This sloping surface of the Kansan is leached and humus stained, and the Illinoian till mantles it with a bed of nearly uniform thickness, thus presenting an upper surface nearly parallel with that of the eroded Kansan. In the autumn of 1894 the writer observed several exposures of a soil and weathered zone in ravines in western Scott and eastern Muscatine counties, between what are interpreted to be the Kansan and Illinoian till sheets. They are not conspicuous in eastei-n Muscatine County, but may be seen both north and south of Blue Grass, in Scott County. The exposures noted are not sufficiently deep to show the lower till sheet to good advantage, but the upper is well displayed and has the characteristic appearance of the Illinoian. Its thickness is but a few feet — in some places only 6 or 8 feet, and seldom more than 15 feet. The Yarmouth soil and weathered zone is represented by a gummy black or gray clay, changing below to a reddish-brown till. The Sangamon soil and weathered zone is represented by a similar dark gummy clay and a leached and reddened till surface. The lowan loess in this locality is only about 8 feet in depth, and is more compact than the bluff loess found in Davenport. At Muscatine the party of geologists above mentioned examined exposm-es in the east part of the city, in the east bluif of Mad Creek, and east from there on or near Second street and on Park avenue. These all occur in a lowland tract bordering the lower course of the creek and occupying the interval between the creek and Mississippi River. Its general elevation is about 80 feet, and the highest points barely reach 100 feet above the low water in the river. The latter are found in a low ridge following the bluff of the Mississippi. , This lowland carries on its sm-face a nearly pebbleless silt several feet in depth, at the bottom of which there are occasional tliin deposits of sand resting on till. The tliickness of silt and sand is scarcely 10 feet, or less than one-half of the tliickness of the lowan leess on neigliboring uplands. It seems doubtful whether the deposit is of lowan age or is to be correlated witli the loess. The -s-iew that it is alluvial seemed to us more probable. The till beneath this silt and sand was found to carry numerous large bt)wlders, some of them being STRUCTURE OF THE DRIFT BORDER. 47 at its surface. It also presents the crumbling texture characteristic of the lUinoian till sheet. It shows very little surface leaching, response to acid being readily obtained at a foot or less. This absence of a marked weathered zone was interpreted to be due to removal by a stream which deposited the sand and silt, rather than to the time interval being too brief for the development of a weathered zone. The slig-ht inequalities in its surface appear to, be due to erosion. This till is referred with some confidence to the lUinoian because of its physical texture and characteristics. Its thick- ness, as exposed on Second street, is about 30 feet. Beneath the till there are beds of fine sand and silt, in the midst of which are thin layers of clay, bearing pebbles up to 2 inches or more in diameter. Similar beds in the southwest part of Muscatine separate the Illinoian and Kansan till sheets, as shown below. In the southwest part of Muscatine the altitude of the Mississippi bluff is 160 to 200 feet above the river, and a remarkably full series of diift deposits is, or has been, exposed. In 1894 a grading on Grreen street afforded an excellent exposure of the upper part of the series, beginning at a level about 165 feet above the river and extending down 50 feet, but this is now concealed by grass. The lower part of the bluff is still exposed in the large clay and sand pits west of Green street. The exposure on Green street was examined by the writer when freshly graded (in 1894), and those west of Green street were examined by the party of geologists in November, 1897. The sections are as follows: Section on Green street, Muscatine, Iowa. Feet. lo wan loess, partly eroded 10 Brownish-black silt at base of loess , ^ Uto 2 Pebbly black soil (Sangamon) 3 Leached brown till (Illinoian) 6 Brown till, unleached, many bowlders near base (Illinoian) 12 Calcareous silt 6 to 8 Calcareous till of brown color, probably Kansan 10 Section on Mississippi bluff west of Green street, Muscatine, Iowa. Teet. Loess, perhaps notinsitu to 5 Till of brown color, eroded, of fri.ible crumbling texture, characteristic of Illinoian drift. . . 1-5 to 25 Beds of sand with even upper surface but uneven lower surface, containing a few bowlderets and cobblestones, but not as a rule stony 5 to 12 Gray till, with vertical cracks lined with brown material, probably Kansan 8 to 20 48 THE ILLINOIS GLACIAL LOBE. Section on Mississippi Muff west of Green street, Muscatine, Iowa — Continued. Feet. Disturbed beds of sand with folds that appear to have a i^revailing east-west treud, us if shoved from the north 4 to 12 Blue-black till with fragments of wood, very thickly set also with small stones and very calcareous, not characterized by weathered seams, possibly pre-Kansan, exposed only a few rods to 8 Peaty bed, exposed only for a few feet 4 to 1 Sand, perhaps from decomposed Coal Measure Sandstone 1 to 2 Coal Measure Sandstone exposed at bottom of pit at level probably 50 feet above river. Total 60 The blue-black till at the base of this exposure is thought by Bain to be very similar in physical texture to some of the supposed pre-Kansan deposits of southern Iowa. The writer has observed several instances of similar material near the bottom of the drift series in southeastern Iowa. It is thought best not to include it in the Kansan unless these suspicions are removed. In the Muscatine cemetery, on the bluff back of the exposures just described, at an altitude about 200 feet above the river, a well passed through 215 feet of glacial deposits, including loess and sand. The drift is mainly blue till, but beds of sand such as outcrop in the exposures near Green street were passed through. For a few miles in the portion of the Illinoian drift border adjacent to the southwestern flowing portion of Cedar River, in Muscatine County, sand dunes and a general coating of sand, drifted probably by wind from the plains bordering the Cedar River, form a mantle of considerable depth on the crest of the terminal ridge, and conceal the structure of the ridge, so that wells afford the only means for obtaining information concerning it. Several deep wells have been made which penetrate from 120 to 300 feet of drift, the least depth at which rock was found being- 120 feet. These wells usually penetrate a large amount of till, but there are thin beds of sand associated with the till at various levels. In some cases a hard till is found at considerable depth, which, it is probable, is as old as the Kansan, and possibly is pre-Kansan in age. The following list of wells in Musca- tine County will serve to set forth the variatioiis in sti'ucture and the great depth of drift. Tlie list begins at the noi-theast part of the county and pro- ceeds southwestward along the ridge. For. several of the sections the writer is indebted to Prof J. A. Udden. STflUCTUEE OF THE DEIFT BORDER. Beep loells along Illinoian drift border in Muscatine County^ loica. 49 Owner or location. Altitude above tide. Depth. Kemarka. Feet. Feet. S. Hayden, sec. 8, T. 78, E. 1 E 800 120 Mainly till ; inflammahle gas from near bottom of drift. Sfip 33 T 78 R 1 E . 730 261 Clay, 80 feet; quicksand, 8 feet; coarse sand near bottom. Sec 9T78E1'W 710 240 Sand, or sandy till, 90 feet ; blue clay, 140 feet; sand and gravel, 10 feet. W. Feldholm, 2 miles south of 750 100 Silt, 5 feet; sand, with few pebbles, 30 Durant. feet; hard blue till, 65 feet. Three miles south of Wilton 720 300 No rock entered. J. Denkman, sec. 12, T. 78, R. 1 W .. 770 158 Clay, 140 feet; silt and sand, 18 feet; rock at bottom. F. D. Wood, sec. 27, T. 77, E. 3 W. . . 750 208 Mainly blue clay with few pebbles; no rock struck. A. Wiggam, sec. 10, T. 76, R. 3 W. .. 750 170 Loess, 12 feet; yellow tiU, 38 feet; grav- elly sand, 25 feet; blue till, 25 feet: yellow cemented gravel, 10 feet ; very hard blue till, 60 feet; sand, 8 feet. Sec. 30, T. 76, E. 3 W 720 154 Mainly till; gravel at bottom. L. Eppelry, 3 miles north of Letts. 735 200 No rock entered. A. Cone, sec. 24, T. 76, E. 4 W 660 200 Till, 130 feet; very hard till, 60 feet; sand at bottom, 10 feet. In northern Louisa County, near Letts, several wells have obtained inflammable gas in sand below till at depths of 100 to 150 feet. These wells are situated just within (south of) the ridge marking the limits of the Illinoian drift, at a level perhaps 50 feet below its crest, or about 675 feet above tide. It is reported by the residents that beds of black muck and peaty material are found closely associated with this gas, and it is probable that the gas is derived from the decomposition of organic matter in these beds. The horizon seems rather low for the Yarmouth beds, unless the Kansan till sheet has been eroded. Prof. F. M. Witter, of Muscatine, Iowa, has presented a brief discussion of these wells in the American Geologist.^ The drift in the vicinity of Columbus Junction may exceed 300 feet in depth. A well made by Dr. Daniel Overhalt in the Iowa River Valley, near Columbus Junction, at a level about 130 feet below the uplands, ' Am. Geologist, May, 1892, pp. 319-321. MON XXXVIII- 50 THE ILLINOIS GLACIAL LOBE. reached a depth of 164 feet without entering rock; the bottom of the well is estimated to be but 416 feet above tide. The following- section of this well is reported by the well diiller, L. Williams, of Columbus City: Section in loell in Iowa Biver Valley near Columbus Junction. Feet. Alluvium y Blue pebbly clay 72 Sand 2 Blue clay 14 Sand 68 Total 164 Di-. Overhalt has a well on the bluff back of Columbus Junction at an altitude 130 feet above the well just noted, which reached a depth of 166 feet. It penetrates about 35 feet of loess and yellow till, beneath which it is mainly in a blue till to within 6 feet of the bottom, where sand and gravel are struck. It is probable that the blue till in this and the following- two sections is Kansan. A well made for Hon. J. W. Garner at Columbus City penetrated only 13 feet of loess and yellow till, beneath which 157 feet of blue till was passed through before a water-bearing- sand was found. L. Williams's well, in Columbus City, passed through 20 feet of loess and yellow till and then penetrated 108 feet of blue till before entering water- bearing sand. Within 2 miles west or south of Columbus City rock is found at depths of only 20 to 40 feet, and the drift is largely a yellow till. Near Cairo, in Louisa County, Iowa, two wells on the crest of the outer ridge of the Illinoian drift sheet, at an altitude of about 750 feet above tide, reached a depth of 130 feet without encountering rock. They are mainly through till, much of which is probably Kansan. On the outer face of the ridge, near the base, at an elevation of 50 feet below the crest, a well was sunk by R. Cotter which enters rock at about 50 feet. Rock is also exposed in the bluff of Long Creek, north of Cairo, beneath about 60 feet of drift, mainly till. Along the outer ridge of the Illinoian drift in northwestern Des Moines County several deep wells have been sunk, some of which penetrate a bed of peat or muck at about the level of the base of the ridge and the surface of the Kansan sheet of drift. It is here that the Yarmouth section given above (p. 42) is found. In some places along the outer ridge of the Illinoian drift wells have STRUCTURE OP THE DRIFT BORDER. 51 passed below the level of the outer border plain before entering- the black muck which is thought to separate the lUinoiau drift from the Kansan. In such cases the well is supposed to have struck into a valley which had been excavated in the earlier sheet of drift, though there is a bare possibility that an older soil horizon is struck. The following section of a well on the farm of F. Smith, about a mile south of Yarmouth, will illustrate the condition just mentioned: Section in well on farm of F. Smith, a mile south of Yarmouth, loica. Teet. Yellow till, becoming gray below (Illinoian) 36 Sand, with thin beds of blue clay and also of cemented gravel, probably in part Illinoian and in part alluvial 73 Black muck, containing wood (Yarmouth) 6 Sand and gravel, probably alluvia] 8 Gray silt, apparently pebbleless, probably alluvial 15 Blue till (Kansan) 42 Depth 180 This well is on the crest of the ridge at a level 60 or 70 feet above the outer border plain. The black muck is therefore at a level about 40 feet below the plain. A well in the neighboring section on the south, at an ele- vation 25 feet lower, enters rock at a depth of 182 feet. One of the thickest drift sections found along this drift border is in a well made by Anton Totemeir near New London, Iowa, in sec. 19, T. 71, R. 4 W., which struck rock at a depth of 276 feet. The section of the well indicates that only the upper 40 feet should be referred to the Illinoian di-ift sheet. The section as reported by Mr. Totemeir is as follows: Section in well of Anton Totemeir, near Neiv London, loica. Feet. Pebbly yellow clay (Illinoian) 30 Pebbly blue clay (Illinoian) 10 Deeply stained, reddish-browu pebbly clay (Kansan) 12 Blue pebbly clay, with thin beds of sand, possibly including pre-Kausan as well as Kansan 224 Total 276 The well mouth being about 750 feet above tide, or 240 feet above the Mississippi River in Burlington, the rock floor at this well is but a little lower than the bed of the present Mississippi at Burlington. Of the several wells along this ridge in Des Moines County none have been found to enter rock at less than 120 feet, and probably at least half this drift is older than the Illinoian. 52 THE ILLINOIS GLACIAL LOBE. Along tlie ridge in southeastern Henry County, as in northwestern Des Moines County, wells not infrequently pass through a bed of muck or peat at the base of the Illinoian drift sheet. In a well made bj- Andi-ew Johnson, li miles south of New London, there were logs and wood, occu- pying a space of nearly 4 feet, found at a depth of 40 to 45 feet from the surface. The writer obtained specimens of the wood and of peaty material associated with it, which await specific identification. Mr. Johnson reports the section of the well to be as follows : Section in loell of Andreio Johnson, 1^ miles south of Neic London, Iowa. Feet. Yellow clay, without pebbles (loess) 6 Pebbly yellow clay (Illinoiau) 20 Sand 3 Blue pebbly clay (Illinoian) '. 12 Peat and wood (Yarmouth ) 4 Gray gummy clay, with few pebbles (Yarmouth) 10 Total 55 A well made by J. M. Lee, 3 miles northeast of New London, passed through a bed of black muck containing wood, just before entering rock, at a depth of 105 to 110 feet. This probably underlies the Kansan sheet of drift. The drift of Lee County, as of counties to the north, belongs mainly to the sheet which underlies the Illinoiau. Numerous exposures, and also well sections, show the Illinoian drift to have a thickness of but 20 to 30 feet on the plain east of the terminal ridge, and 30 to 70 feet on the ridge. The average thickness of the combined drift sheets in the county is 23i'ob- ably at least 100 feet. On the borders of the Mississippi the thickness exceeds 300 feet, as shown bv a well on the bluff north of Fort Madison and another at Mont Clare. The deposit of loess coating the Illinoian drift in this county has an average depth of only about 6 feet. Between the loess and the Illinoian drift there is a well-defined soil (Sangamon), nsualh" of black color. At the top of the Illinoian drift there is often a mucky clav containing only fine pebbles, but the greater part is a stony till with occasional bowlders and numerous rock fragments 1 to 6 inches in diameter. As noted above, this sheet of drift is often so thoroughly leached from top to bottom tliat no response with acid can be obtained. Whether this feature is notably characteristic of the drift border for some distance to the north ;ind sontli has not been determined. STRUCTURE OF THE DRIFT BORDER. 53 Along the crest of the terminal ridge from Skunk River southward to West Point numerous wells have been sunk to a depth of 60 feet and a few to greater depth. They penetrate till the greater jjart of the depth, though in one instance the lower 50 feet is sand and gravel. The thickness of the drift ranges from about 80 to 120 feet or more. Of this the lower 40 or 50 feet is older than the Illinoian. Several of the wells have passed through peat, containing wood, at about the level of the base of the ridge, and there is an excellent exposure of a black muck below the Illinoian drift in a ravine about a mile northeast of West Point on the east slope of the ridge. At this exposure the following section is found: Section in a ravine about a mile northeast of West Point, Iowa. Feet. Yellow silt or loess (lowan) (> Soil, "with aahy gray subsoil (Sangamon) 5 Brown till containing many bowlders (Illinoian) 15 Black mucky soil witli gray subsoil (Yarmouth) 6 Brown clay with few pebbles (Kansan) exposed 15 Total 47 The deepest well section obtained on this ridg-e is at the residence of Andrew Foggy, sec. 16, T. 69, R. 5 W., and this differs from other well sections in that neighborhood in containing a large amount of sand in tlie lower part. From observations in a neighboring ravine and Mr. Foggy's statements concerning material penetrated in the well, the following section is prepared: Section in well of Andrew Foggy, near West Point, Iowa. Feet. Y'ellow silt or loess (lowan) 6 Black soil with gray subsoil (Sangamou) 4 Yellow till (Illinoian) 20 Sand, aii'ording weak vein of water (Illinoian) 6 Blue till (Illinoian) 33 Sand and peaty material, underlain by a fine gravelly sand (alluvial and Kansan) 50 Limestone 12 Depth 131 It is probable that the Illinoian drift extends to the peaty material at a depth of 70 feet, for the well stands upon probably the most elevated point on the ridge in this county, at a level nearly 70 feet above the outer border plain. A neighboring well in the same section, on the farm of F. Timpe, penetrated about 12 feet of loess-like silt and slightly pebbly yellow clay, at which depth a very calcareous, sandy, yellow till is entered. This 54 THE ILLINOIS GLACIAL LOBE. changes to a blue till within a few feet. A large amount of wood was in the blue till near the bottom of the well, at a depth of 25 to 30 feet. The wood, however, is incorporated in the till in the same manner as bowlders or pebbles, and does not indicate a soil horizon. The well appar- ently terminated in the lUinoian drift. On the plain east of this ridge a black soil (Yarmouth), which separates the Illinoian sheet from the underlying drift, has been noted in wells at the following depths: Depth to blacl- soil (Yarmouth) in wells on the plain near jDenmarTc, loica. C. A. Flohrer, sec. 10, T. 69, R. 5 W "\V. Hawkins, see. 13, T. 69, R. .5 W E. Newton, sec. 24, T. 69, R. 5 W C. H. Burton estate, sec. 25, T. 69, R. 5 W Thomas Saunderson, sec. .S5. T. 69, R. 5 W Benj. Krehbiel, sec. 36, T. 69, R.5 W Mr. Holstein, sec. 30, T. 69, R. 4 W 5. Van Tuyl estate, sec. 30, T. 69, R. 1 W . 6. B. Brackett. Denmark James Conaro, Denmark William Blackiuton, Denmark Dr. William Sloat, Denmark Public well, Denmark Altitude A.T. Depth. Feet. 725 715 725 720 720 720 725 715 700 700 700 700 700 Feet. 30-32 16-20 35-40 30-35 20-22 35-40 45-48 35-37 20-26 19-24 26 25 20-30 The wells at Mr. Flohrer's and Mr. Hawkins's pass through several feet of ash-gray clay, apparently a subsoil, immediately below the black soil. Exjiosures on ravines in this part of the county sustain this interpretation of soil and subsoil. The Van Tuyl well has the following series of beds: Section in tcell on S. Van Tuyl estate, near T>enmarl;, loira. Feet. Yellow silt or loess, slightly calcareoiis and containing a few small pebbles near base (lowan) 7 Brownish-yellow clay, with few pebbles anil but slightly calcareous (Illinoian^ 10 Brownish-yellow till, i>ebbly and calcareous (Illinoian) 8 Blue clay, with few pebbles (Illinoian) 10 Blaik mucky soil, with wood (Yarmouth) 2 Brownish-yellow till (Kansan) 12 Hard blue till (Kansan) 6 Limestone 4 Total 59 STRUCTUEE OF THE DEIPT BOEDER. 55 The well at Dr. Sloat's penetrates the following beds: Section in toell of Dr. William Sloat, in Denmarli, loica. Feet. Yellow Bilt or loess (lowan) 6 Brownish-yellow clay, slightly pebbly (lUinoiau) 20 Mucky clay, largely of gray color and containing a few small pebbles (Yarmouth, and possibly Kansau) 15 Brownish-j'ellow till (Kansan) 10 Dark- blue till, with beds of saud yielding water 5 Total depth 56 The well at Mr. Conaro's was carefully observed by the writer, during its excavation, and has the following section: Section in icell of James Gonaro, in Denmark, lotca. Feet. Yellow silt or loess (lowan) 9 Brown clay, not calcareous, with occasional pebbles, 3 inches or less in diameter (Illinoian) 10 Soil and grayish subsoil, slightly pebbly, not calcareous (Yarmouth) 5 Brownish-yellow till, leached for 6 feet at top, remainder very calcareous (Kansan) 25 Total depth 49 At Mr. Blackiuton's well, which was also personally observed during its excavation, the upper 20 feet is a thoroughly leached clay; the remainder is calcareous till of brownish-yellow color, Avhich includes thin beds or pockets of sand and extends to the rock, which is struck at a depth of 54 feet. In this connection it may be remarked that several of the wells in the vicinity of Denmark penetrate yellow till below the Illinoian drift sheet to a depth of 25 or 30 feet, there being little or no blue till above the rock. At the public well, however, a blue-black till occurs at 52 to 63 feet. Expo- sures on ravines both north and south of the village also have a dark blue- black till beneath the yellow at a level 15 or 20 feet below the top of the Kansan sheet of drift. Possibly this is pre-Kansan till. On the bluff north of Fort Madison a well made at the residence of Mrs. Heitz reached a depth of 315 feet without entering- rock. Blue till was entered at 27 feet, which, with the exception of a thin sand bed, presents a solid mass 260 feet in thickness. Beneath this till, in the lower 26 feet of the well, there is a cemented gravel. Exposures in neig'hboring ravines indicate that the Illinoian drift sheet on the bluffs at Fort ]\Iadison is not more than 20 feet in depth. The thick bed of blue till passed through in the well is apparently as old as the Kansan, and includes perhaps an earlier drift sheet. Along the Mississippi bluff above Fort Madison there 56 THE ILLINOIS GLACIAL LOBE. are exposures of drift 180 feet in height. The upper .50 or 60 feet consists of alternations of till with sand or gravel, and is referred mainly to the Kansan. The remaining 120 feet is a nearly solid mass of dark-blue till, which is, however, characterized by stony parts that give it the appearance of being interbedded with gravel and cobble. These bands of stony material are very nearly horizontal. It is not certain that this should be referred to the Kansan; possibly it is pre-Kansan. Many bowlders are accumulated along the base of this bluff. A strip covered with these bowlders, having a length of 8 rods and a width of 3 rods, was carefully exajnined. It in- cluded 107 bowlders, with an average diameter of about 3 feet. The largest three exceed 6 feet in diameter; the smallest included in the count were at least a foot in diameter. Upon classifying the bowlders it was found that red granite greatly predominates, there being 85 specimens. Of the gray or dark-colored granite only 6 were found. The greenstones are repre- sented by 10 specimens. The two remaining specimens were limestone. About one-fourth of the bowlders were glaciated on the sides exposed to view; probably inany others are glaciated on the under side. The jjro- portion of red granite is exceptionally large for this region, though it is probable that at least half the bowlders are of this class. These bowlders are probably largely from the dark-blue till. The artesian wells in the Mississippi Valley at Fort Madison enter rock at a level about 135 feet below low water in the Mississippi, or at about 365 feet above tide. The drift is mainly blue till, such as is exposed in the neighboring bluff. It is older than the Illinoian, and possibly is pre-Kansan. This blue till is covered to a depth of 10 to 40 feet by alluvial sand, which in places extends to near the level of the river bed. The artesian well on the Mississippi bluff at Mont Clare, about 12 miles southwest of Fort Madison, penetrated 305 feet of drift. It is reported to be mainlj^ through clay for a depth of 250 feet, beneath which there is sand extending to the rock. This well, it should be noted, stands just outside the limits of the Illinoian drift. The drift, therefore, like that at Fort Madison, belongs to an earlier sheet than the Illinoian. The Illinoian drift ])robably extends to the western limits of the upland in Hancock County, Illinois, tln-oughout the entire length of the county. The drift, however, can not be referred entirely to the Illinoian invasion, for there are southeastward-bearing strife in the western part of this county. STKUOTUEE OF THE DRIFT BORDEE. 57 which indicate that the earlier ice invasion, from the Iowa side, crossed the Mississippi into western lUinois. Instances of a soil between till sheets have also been found in this county, as in the counties of southeastern Iowa just discussed, and this soil is referred to the Yarmouth interglacial interval. The distance to which the lUinoian sheet overlapped the earlier one is not known. It is probable that the heavy deposits of drift found in central and southern Hancock Count)- should be largely referred to the earlier invasion. A well made by William McCuen on the east slope of the terminal rido-e of the lUinoian drift, about 4 miles south of Hamilton, has the fol- lowino' section : a Section in icell of William McCrien, about 4 miles south of Hamilton, Illinois. Peet. Yellow silt or loess (lowan) '-' Soil auil groy subsoil grailing downward into a pale till (Sangamon and Illinoian) 22 Blue till (probably Illinoian) ^ Peaty muck witb wood (probably Yarmouth) ^ Pebbly clay of bluish color (probably Kansan) 38 Total depth - - - "'^ Mr. McCuen reports that other wells in the neighborhood have pene- trated a similar buried peat. It seems probable that this peat is at the base of the Illinoian sheet, though it may possibly be interbedded with other deposits. From near Carthage southward past Stillwell there is a filled valley whose position is revealed by the deep wells, the filling being so complete that there are no surface indications of the course. The artesian wells at Carthage penetrate 214 feet of drift, and several wells between Carthage and Stillwell reach a depth of nearly 200 feet without entering rock, and one a depth of 220 feet. A well at Owen's mill in Stillwell enters rock at 207 feet. As the surface elevation at these wells is nearly 200 feet above the Mississippi River, those which strike rock enter it at about river level. Probably the deepest part of this filled valley is cut to a much lower depth, for the rock floor of the preglacial Mississippi is 100 feet or more below the level of low water in the stream. In nearly all these deep wells the drift is mainly a blue till similar to that exposed in the Mississippi bluff near Fort Madison, and, like that near Fort Madison, is probably older than the Illinoian. In some wells the blue till is entered at a depth of onl}' 20 to 25 feet, but in the majorit}- it is struck at 35 to 40 feet. 58 THE ILLINOIS GLACIAL LOBE. On the poi-tion of the ^Mississippi bhiff above Hamihon the drift is only 20 or 30 feet in (le])th and is largely of sandy constitution. It seems probable that some modification of the glacial drift has resulted through drainage connected with the melting of the Illinois glacial lobe. The evi- dences of a delta-like filling at the lower end of the Des Moines rapids, near Warsaw, are discussed on another page. In Adams Countv the Illinoian sheet has a series of ridges developed near the border. The outermost one lies but a short distance east of the Mississippi bluff, and is interrupted by wide gaps through which the streams find passage into the Mississippi. The inner ridges occupy a portion of the divide between the lUinois and Mississippi rivers in the central and south- eastern part of the county. These ridges differ greatly in structure from point to point. The portion of the outer ridge north from Bear Creek is composed largelj' of ordinary brownish-yellow till, but throughout its con- tinuation south of Bear Creek, from near Mendon southward past Eubanks, it contains a large amount of sand and gravel. The upper 30 or 40 feet, however,, is often of clayey constitution, and this included, probably, the entire Illinoian sheet as it extends about to the level of the base of the ridge. In places the sand and gi-avel beneath this ridge is thought to be of pregla- cial age, and it seems not improbable that the portions which contain Canadian rocks or other erratics may be composed in large part of slightly modified preglacial material. The material thrown out from wells at Mendon was carefully examined and was found to be a quartz sand, of orange color, entirely free from calcareous material. But exposures of a similar sand near Eubanks were found to include occasional Canadian rocks in their upper portion, as if the sand had been worked upon by the ice sheet and redeposited, together with some of the material contained in the ice. Upon following this ridge southeastward to IMill Creek a change to till is found, and the valley of Mill Creek, at the point where the ridge crosses, is shown by wells to have been filled to a depth of 150 feet or more with a clayey deposit which from description appears to be till, there being numerous pebbles incorporated in it. A well made at the residence of Mrs. Ihrig, on the west bluff of Mill Creek, in sec. 15, T. 2 S., R. 8 W., reached a depth of 155 feet without encountering rock. It was mainly through clay, except a few feet of sand at the l)ottom. A well on the east bluff of the creek, in section 12 of the same township, is 200 feet in depth and is STRUCTURE OF THE DRIFT BORDER. 59 thought to have entered rock only 40 feet; it also is reported to have been largely through clay. On the elevated district near Payson wells penetrate alternations of clay and gravel to a depth of 60 feet or more. A well made by Mr. Barnard, 1 mile west of Payson, after penetrating 60 feet of clay and gravel, entered a red clay, apparently formed from the limestone which underlies that region. In some places the gravelly beds of the drift seem to rest directly upon undecayed rock sui-face. A small drift ridge is traceable southeastward from the village of New- ton (Adams post-office), on which wells have been sunk to a depth of 75 or 100 feet without entering- rock. The town well at Newton is reported to be mainly tlxi'ough clay, with a few feet of gravel at bottom. A well at Mrs. Wittemeyer's, on the crest of the ridge, about a mile southeast of Newton, reached a depth of 82 feet and apparently j)assed through a buried soil between sheets of till. Exposures of a buried soil are to be seen near the level of the base of the ridge in the road leading south from Mrs. Wittemeyer's, in sec. 35, T. 2 S., R. 7 W., but at that place it is underlain by sandy gravel. The following is a section of the well as reported by the owner: Section in icell at Mrs. Wittemeyer's, a mile southeast of Newton, Adams County, Illinois. Feet. Yellow clay wltliout pebbles (lowau) 10 Pebbly yellow clay (lUinoian). 30 Mucky gray clay (probably a Yarmouth soil) 7 Sandy and pebbly clay grading downward into sand (Kansan) 35 Total depth 82 On the plain northeast of this ridge, from the village of Burton east- ward to Liberty, the ravines expose a yellowish gummy clay, containing few pebbles to a depth of 50 feet, which is referred to the Illinoian. There do not appear to be large pebbles or bowlders in such number as usually occur in the typical till. Farther south, in the vicinity of Plainville and eastward from that village, the ravines expose a large amount of cherty gravel and cobble in the lower part of the drift, but the upper part, to^a depth of 20 feet or more, is usually a clay containing but few pebbles. This phase of the drift, as noted below, extends across Pike County and characterizes the extreme border of the Illinoian sheet. It is probable that the chert is a residual product from the chert}^ limestones of that locality. 60 THE ILLINOIS GLACIAL LOBE, Along the divide between the IlUnois and Mississippi rivers, from the southeast corner of the county northwestward to the vicinity of Liberty, there is a ridge made up in part of till and in part of sand and gravel. In the vicinity of Kingston (Fairweather post-oifice) wells along the crest of the ridge have reached a depth of 90 feet without entering rock. The ravines near this village expose an ash-gray soil (Sangamon) below the loess, and beneath this a brown gummy clay, slightly pebbly, with occa- sional bowlders, which is probably of lUinoian age. This clay is seldom more than 15 feet in depth, and is underlain by sand containing- few pebbles. In the ^^cinity of Beverly the sand is absent and a blue till appears below the brown g-ummy clay. A well at J. Sykes's, about a half mile east of Beverly, is thought to have entered preglacial sand in its lower part. The well is an excavated one, 6 feet in diameter, and several wagon loads of the sand were thrown out on the dump, where excellent opportunity for comparing it with the glacial dejaosits was afforded. An examination of these deposits, supplemented by information furnished by Mr. Sykes, enables the writer to present the following section: Section in icell of J. SyTtes, a half mile east of Beverly, Adams Goimfij, Illinois. Peet. Loess and gummy brown clay with few pebbles 35 Gray sand 3 Blue till, very stony, with largo bowlders and fragments of wood 27 Gray sand and gravel, calcareous 5 Orange-colored quartz sand, noncalcareous 14 Total depth 84 This well is located in an elevated part of the county, about 360 feet above the Mississippi River. A similar deposit of sand was found in a well in the village of Beverly at a depth of 56 to 76 feet, or very nearly the same elevation above tide as the well at Mr. Sykes's, the well mouth being on ground 16 or 20 feet lower than the Sykes well. The immerous ravines leading eastward from this ridge toward McKees Creek may afford expo- sures of the sand, but none were noted by the writer. Along the portion of the Illinois-Mississip])i divide between Liberty and Fowler the drift is very thick and its lower part is of peculiar constitution. Well drillers and several of the residents report that after a depth of about 30 feet is reached a blue-black clay, with sand partings and with much wood, is entered, which extends down nearly <>r (piite to the limestone underlving STRUCTURE OF THE DRIFT BORDER. 61 that region. The wi-iter had opportunity to examine the material thrown out of a well at the residence of James Loveless, in see. 34, T. 1 S., R. 7 W., and found it to be a blue-black silt, very calcareous, and containing onlv minute pebbles and sand grains. Several specimens of wood from this silt which were inspected by the writer also carried a coating of similar silts. Above the silt there is ordinary till, except a thin coating of loess at the surface and pockets or thin beds of sand or gravel or silty clay in the till. In Mr. Loveless's well the following- section appears: Section in well of James Loveless, between Liberty and Foicler, Adams County, Illinois. Feet. Yellow silt or loess 6 Ashy soil and subsoil containing a few small pebbles 12 Calcareous yellow till 22 Gray gummy clay, resembling soil, noncalcareous 2 Calcareous yellow till 18 Blue-black silt, very calcareous 2 Total depth g2 At the county infirmary, in sec. 11 of the same township (T. 1 S., R. 7 W.), a well struck rock at a depth of 165 feet. The lower 100 feet of the drift is a blue silt apparently similar to that in Mr. Loveless's well. A shallower well at the infirmary obtained water in sand and gravel at a depth of 40 to 58 feet. A well on the farm of Mr. Henr}^, in sec. 3, within a mile of the infirmar}-, has a section similar to that of the deep infirmary well and entered rock at 160 feet. Several of the wells in the village of Libert}^ penetrate a similar blue- black silt, entering it at about 60 feet and continuing in one case to a depth of 90 feet Avithout entering rock. In the vicinity of this village, however, rock is occasionally entered at a depth of 50 feet or less, and only 2 miles east of the village and at a slightly higher elevation rock is struck at only 25 feet. There is a low ridge leading from the village of Coatsburg eastward 5 or 6 miles on which the wells occasionally enter a blue-black silt similar to that found on the district just described. A well at the mill in Coatsburg is reported to be mainly through pebbly clay to a depth of 65 feet, beneath which there is a blue clay with sand jiartings and wood embedded, which was penetrated 30 feet Avithout entering rock. A boring for coal a mile east of Coatsburg is discussed in the Geology of Illinois because of the occur- rence of this blue-black material in the lower portion of the drift, which is 62 THE ILLINOIS GLACIAL LOBE. thfere considered a " post-Tertiaiy soil" older than the drift proper, and formed xmder very different conditions. The following is the section there published: Section in a horinfj for coal, a mile eastofCoatsburg, Adams County, Illinois. Feet. Soil and yelloTv clay 6 Blmsh-colored clay and gravel 15 Clay with large lio wlders 40 Black soil ■ 2+ Clay (stratified) 6 Very tough blue clay 20 Rock entered at 119 It seems not improbable that the silt under the till of central Adams Count}^ is attributable to ponded waters held in front of the Keewatin ice sheet in the Kansan stage, for that ice sheet apparently crossed the Missis- sippi into Illinois near Hannibal, Missouri, and covered the lower courses of its eastern tributaries. In Pike County typical till has been seen at but few points. The several drift ridges which traverse the county are composed largely of clay and sand in which only a few small pebbles occur. There is, however, on the borders of Hadley Creek, in the northern part of the county and the adjacent portion of Adams County, considerable waterworn chert in the base of the drift. This chert is apparently a residuary product from the decay of cherty limestone in that region, but it was worked over to some extent by the ice sheet and its associated waters, and this has resulted in the introduction into the chert of occasional bowlders and smaller stones of distant derivation, as well as the wearing and rounding of the chert frag- ments. These chert beds are in places 10 or 15 feet thick. They usually present the appearance of gravel beds, there being very little clay present. Exposures were found, however, east and southeast of Baylis, on the west side of Bay Creek, in which a large amount of clay is mingled with the chert and other stony material. In the southwest part of the count}-, which appears to have been but slightly glaciated, if at all, the chert beds remain intact at the surface of the limestone. Quarries along the east bluff of the Mississippi afford good exposures. A few well sections and hillside sections obtained in the vicinity of the drift border are here given to illustrate and make clearer the above state- ments. STRUCTURE OF THE DRIFT BORDER. Q ] Hillside exposures on the line of Pike and Adams counties, in R. 5 W., have a bed of cherty g'ravel with occasional Canadian rocks resting on the sui'face of the limestone, and covering- it to a depth of 5 to 15 feet. Above this gravel there is usually 40 or 50 feet of clay containing very few pebbles. The deeper exposures show it to be of a gray color, but the surface portion is yellow. Capping this clay is a thin deposit of loess, separated in places fi'om the clay by a gray or ashy (Sangamon) soil. At the residence of A. Hill, 2 miles north of Baylis, on the crest of tlie main drift ridge, a freshly excavated w ell was found to have the follow- ing section: Section in well of A. Hill, 3 miles north of Baylis, Pike County, Illinois. Feet. Bro^n clay with few pebbles 25 Graj' sand 10 Gray clay, nearly free from pebbles 33 Total depth 68 At Baylis an experimental boring for water reached a depth of 90 feet without entering rock or penetrating coarse material of any kind. The upper 30 feet consisted of 5^ellow clay and the remainder of fine sand. This well is located on the crest of the main ridge, at an altitude about 400 feet above the Mississippi River. East and south from Baylis numerous exposures are found in which a pebbly brown claj^ underlies the loess at a depth of 8 or 10 feet. In the northeast part of the county, in the vicinity of New Salem and Griggsville, and thence north to the county line, the wells and natural exposures reveal only a small amount of stonj" clay, the greater part of the drift being nearly pebbleless. Rock is often entered at 30 or 40 feet, or even less depth. In the vicinity of Time the ravines expose a pebbleless clay, probably a ]Dhase of the loess, to a depth of 20 feet or more, beneath which there is a slightly pebbly brown clay. The village well at Time reached the bottom of this brown clay at a depth of 50 feet, and then penetrated 20 feet of blue clay resembling putty, and terminated at a depth of 70 feet without entering rock. At J. E. Dinsmore's farm, south of Time (sec. 26, T. 6 S., R. 3 W.), a well 60 feet in depth is largely through typical till, exposures of which are to be seen in neighboring ravines. Mr. Dinsmore made a well in sec. 23, in a ravine 30 or 40 feet below the level of the upland plain, which 64 THE ILLINOIS GLACIAL LOBE. penetrated 40 feet of nearly pebbleles.s brown clay, beneath which there is a black muck 5 or (i feet in depth which rests upon a red clay, apparently a residuary product from the decay of limestone. East of Bay Creek, in T. 6 S., R. 2 W., wells along the oiiter di-ift ridge frequently reach a depth of 50 feet, and occasionally 80 feet, without entering rock. From descriptions of the matei'ial, it is probable that ordinary till is penetrated, but no exposures were found. The loess in that locality is about 20 feet in depth. From Pike County the drift border passes to the east side of the Illinois. A typical till constitutes the greater ]oart of the di'ift exposed in ravines along that side of the river in Scott, Greene, and Jersey counties. The loess on the river bluff is usually 20 or 30 feet in depth, but within 8 or 10 miles east of the river it decreases to 10 feet or less. The di-ift forms a deposit pi-obably 50 feet in average depth at the east border of the Illinois Valley, but immediately west of the Illinois, in southern Pike and in Calhoun County, there is scarcely a trace of drift. There are several knolls and ridges of drift a few miles back from the drift border in Grreene and Jersey counties, but no accurate well sections or other exposures of their structure were obtained. The descriptions given by residents, however, indicate that they are composed larg-ely of clay. In Madison County typical till is found along- the east blutf of the Mississippi throughout the entire width of the county, as well as at points farther east. At the immediate border of the valley there is a deposit of loess 30 to 50 feet in depth, but Avithin 10 miles back from the bluff the thickness decreases to 10 feet or less. The till is usually 25 to 50 feet in depth, and where thickest is of a blue color near the bottom. Opposite Madison County, in St. Louis Countv, Missouri, north from the c-ity of St. Louis, deposits of waterworn material of glacial derivation underlie the loess for a, few miles back from the bluff of the river. These deposits contain a few bowlders, 1 to 2 feet in diameter, as well as cobble and gravel. The rock constituents appear to be different from those of the drift in Madison County, Illinois, there being present considerable material apj^ar- ently brought down from the exposures of the sandstone and limestone of Silurian age on the borders of the Mississippi in Calhoun Countv, Illinois, and Lincoln County, jMissouri. The presence of this material suggests water rather th;iii ice transjjortation, and it remains an open question whether STEUCTUEE OF THE DRIFT BOEDEE. 65 the ice sheet reached into northern St. Louis County from the Ilhuois side of the river. On the east bluff of the Mississippi below East St. Loiiis only a small amount of glacial drift has been found beneath the loess deposits, which there cap the bluff to a depth of 30 to 60 feet or more. The drift usually consists of a thin bed of stony material, but in some of the recesses of the bluffs and in ravines exposures of nearly pebbleless clay are occasionally seen. Some of these exposures near Columbia, in Monroe County, reach a depth of 40 to 50 feet. An occasional bowlder a foot or more in diameter is found in these deposits, but stones are very rare compared with their number in the typical till, such as is exposed in the east bluff of the Missis- sippi above East St. Louis. It is probable that the ice sheet extended as far west as the east bluff of the Mississippi in St. Clair, Mom-oe, and Ran- dolph counties, but the deposits there are very much thinner than in drift ridges, discussed later, which traverse the eastern portion of these counties, and which perhaps mark an ice margin at a somewhat later period than that of the maximum extension. The portion of the drift border in southern Illinois, on the slopes of the elevated rock ridge in Jackson, Williamson, and Saline counties, con- tains typical till, but the deposit is seldom more than 20 or 25 feet in depth. In one instance, however, a well in the southwest township of Williamson County was found to have reached a depth of 70 feet without entering rock. The distance to rock is also great in the ^dcinitj" of Murphy sboro, in Jack- son County. The wells and borings for coal often reach a depth of 100 feet, and occasionally 130 feet, before entering rock. The di-ift is reported to be largely sandy material, but the upper portion, exposed to a depth of 50 feet by Big Muddy River, is mainly clsij containing but few pebbles. On the borders of the Ohio Valley, in Grallatin County, Illinois, there is a belt of sandy material several miles in width which is not referred with certainty to glacial deposition. Back of this a typical till sets in, which is exposed in ravines beneath 8 or 10 feet of loess. Wells usually reach the bottom of the drift at 20 or 30 feet, but one 2^ miles north of Ridgway reached a depth of 98 feet without entering rock, and another 3 miles west of Ridgway a depth of 75 feet. In the Ohio Valley at Shawneetown a boring for gas and oil penetrated 112 feet of allu^aal and other deposits MON XXXVIII 5 66 THE ILLIISrOIS GLACIAL LOBE. before entering rock This appears to be outside the glacial boundary, but the material penetrated is probably derived from glacial deposits brought down the valley. In southwestern Indiana the drift in the vicinity of the glacial bound- aiy frequently reaches a depth of more than 100 feet in the valleys; but on the uplands it rarely exceeds 40 feet, and is usually but 10 or 20 feet. As a rule, a deposit of till several feet in depth appears along the drift border, but in places there are only scattering pebbles for a mile or more back from it. The latter feature is most fi-equently found in the liilly parts of the border. The till in the portion of southwestern Indiana south of East White River contains a remarkably small number of bowlders and coarse frag- ments of rock. In places search is necessary to discover a pebble, though in a neighboring exjDosure a large bowlder may be found. In a few locali- ties sand is present instead of clay, but, like the clay, it carries very few pebbles. It is thought that these peculiar ^jhases of the di'ift may be due in part to the character of the underlying rocks (there being a prepon- derence of friable strata which might easily be reduced to clay or sand) and in part to imperfection of drainage conditions, by which the very fine material was all retained in the till instead of being allowed to escape down the valleys, as in regions to the west, where drainage conditions were better. In connection with the fii'st of these causes, it may be remarked that the local rocks throughout the entire region covered by this glacial lobe usually form so large a proportion of the coarse constituents of till that its character is found to vary in a pronounced degi'ee in ' accordance with changes in the underlying rocks. The imperfection of di-aiuag-e in southwestern Indiana attending the ice invasion was such that several lakes were formed in valleys wliich lie outside the di'ift border and whose streams had discharged westward before the ice invaded the territory covered by the ice sheet. These glacial lakes are discussed at some length on later pages, as are also the changes of drainage which resulted from the ice invasion. North from East White River the till usually carries a moderate number of jiebbles, and differs but little from the typical till of the interior portion of the district covered by tlie Illinois lobe. The coarse rock frag- ments are composed largely of sandstone from formations which outcrop in the immediate vicinity of the drift border. Canadian rocks, however, STRUCTURE OF THE DRIFT BORDER. 67 are well represented, and bowlders 4 feet in diameter are occasionally found on the immediate drift border. Eeference will be made to a few of the wells showing thick chift and to characteristic exposures, beginning in Posey County and passing nortiieastward. The thickest drift noted in Posey Coimty is in an abandoned valley which connects the head waters of Big Creek with Black River. One Avell iu this valley, on the farm of Joseph Nesbit, about a mile west of Cynthiana, penetrated 127 feet of drift, and entered sandstone at that depth. The well mouth is only about 420 feet above tide and 80 feet above the neighboring portion of the Wabash River. The driller, T. F. O'Herron, of Haubstadt, reports that the entire depth is a stiff" clay, of which the upper Sf! feet has a brown or yellow color, and the remainder a blue color. On a neighbor- ing farm, owned by Joseph Cale, a well reached a depth of 114 feet without entering rock. In this Avell two thin beds of fine gravel were passed through. Aside from these the drift is a stiff clay, of which the upper 40 feet is yellowish brown and the remainder a blue color. On the head waters of Big Creek, in northwestern Vanderburg County, several wells 40 to 60 feet in dejoth do not reach rock. This valley appears to have been silted up to a depth of 50 feet or more in the portion imme- diately outside the glacial boundary. Wells there are reported to pass thi'ough " clay and quicksand"." In the %dcinity of Haubstadt, within a mile north of the glacial bound- ary, there is a plain in winch several wells have penetrated 40 to 70 feet of di'iffc before entering rock. The upper 20 or 30 feet is yellowish-brown clay and the remainder blue clay. Occasionally the clay maintains a yel- low color to a dejDth of 40 feet or more. The loess in that region, both outside and inside the glacial boundary, is about 12 feet in thickness and is similar in color to the oxidized portion of the underlying glacial di-ift. In the ridged belt near Fort Branch there are several hillside exposures showing a few feet of till with considerable stony material just below the loess, and beneath this a fine sand. The wells along the ridge enter a soft blue clay, called "blue mud," at a dejjth of 30 or 40 feet. Only one well was found which entered rock. This is located at the residence of Lawrence Byers, near the east base of the ridge, and reached rock at a depth of 97 feet. Several wells along the crest of the ridge, 50 to 100 feet in depth, (58 THE ILLINOIS GLACIAL LOBE. do not enter rock. East of this ridge, along- Sand}^ Fork of Pigeon Cre6k, wells are usually obtained at a depth of 25 feet or less. In some instances they penetrate alternations of blue clay and sand beneath the loess, while in other iiastances nothing but sand is found. In some of the ravines lead- ing into Sand}" Fork, a gray gummy clay carrying a few small pebbles immediately underlies the loess. It appears to be stained with humus, and probably represents the Sangamon interglacial stage. A creek exposure in the southwest part of sec. 23, T. 2 S., R. 10 W., shows a red, weather- stained, sandy gravel below the loess. West of the di'ift ridge along Mudd}" Fork of Pigeon Creek, wells usually enter blue clay at about 30 feet, and in several instances have been sunk to a depth of about 100 feet without reaching rock. One well 3 miles west of Fort Branch, on the farm of Henry Lehriug, struck rock at a depth of 114 feet. Two miles farther west, on more elevated ground, rock is struck at 12 to 20 feet. In western Pike County, Indiana, in sees. 13, 23, 24, and 26, T. 1 S., R. 9 W., several roadside exposures of till having a thickness of 5 to 10 feet were found apparently at the extreme limits of glaciation. For several miles east from these sections the thickness of the drift on the uplands seldom exceeds 10 feet, and the loess here is reduced to a thickness of but 5 or 6 feet. In a lowland tract along Flat Creek, in eastern Pike County, which lies near the glacial Ijoundary, the drift has a thickness of 75 to 120 feet or more. At the village of Otwell, which stands in this lowland, Dr. W. M. De Motte made a boring which reached a depth of 119 feet without strik- ing rock, though the well mouth is only 485 feet above tide, and scarcely 85 feet above the neighboring portion of East White River. A boring made by William Bell near the head waters of Mud Creek and Flat Creek, 6 miles west of Otwell, reached rock at a depth of 78 feet, and several other wells within 2 miles north and east are reported by Mr. Bell to have reached rock at 75 to 80 feet. The di'ift in this lowland is reported to be largely a blue mud. There is, however, considerable sand just below the loess, exposures of which may be seen along the ravines and at roadsides. This lowland, as indicated on a later page, was apparently the line of discharge for a part of the Patoka drainage basin into White River, wliich it entered near the junction of the two forks east of Petersl)urg. On the uplands bordering tliis lowland on the north and east, rock is usually entered at 35 feet or less, while on the STEUCTURE OF THE DEIFT BOEDEE. 69 uplands to the south it is found at 6 to 10 feet, there being httle, if any, drift present. As ah'eady noted, in northwestern Dubois County there is a low plain covering about 50 square miles in wliich the loess is underlain by sand. The sand appears to have been deposited in the glacial lake Patoka, formed by the obstruction of the Patoka River by the ice sheet, the preglacial course of the river having been northwestward across this plain into East White River. The plain was built up to a level of about 480 feet above tide, which has been increased to 485 to 490 feet by the subsequent loess deposit. The surface of the sand at the base of the loess is deeply weather- stained, showing that it long antedated the loess in deposition. On the borders of this plain, about 3 miles north of Jasper, in sec. 15, T. 1 S., R. 5 W., an exposure of black soil was found immediately below the loess, which was apparently formed in the Sangamon interglacial stage. The .clay below it contains a few glacial pebbles. In southeastern Daviess County, as noted above, the drift for a mile or two back from the glacial boundary is reduced to a few scattering pebbles. A heavy sheet of till there sets in, which fills the country to a nearly uniform level and produces plains known as "the flats," on which the drift ranges from 20 to 80 feet or more in depth. The plane surface extends nearly to the glacial boundary in the vicinity of Whitfield, Mount Pleasant, and Loogootee, in Martin County. There are, however, scattering pebbles on the hills along the east border of the plain. On a tributary of Boggs Creek, 2 miles north of Loogootee, exposures of till occur 30 feet or more in height, in one of which a granite bowlder 4 feet in diameter was noted. Along much of the boundary from Loogootee to Scotland the drift is very thin, though it apparently forms a nearly continuous sheet. There are low hills along the east border of Daviess County which for several miles inside the glacial boundary show only a thin coating of drift. But the lowlands in that region have apparently been filled to considerable depth. At Scotland and along ravines northeastward there are exposures of sandy till 10 to 20 feet in depth at points within a mile of the apparent limits of glaciation. The hills in that region, however, carry very little drift. In the lowland tract north of Plummer's Creek there are heavy depos- its of sand, which in places are cajDped by a few, feet of fine gravel, apparently a glacial deposit. The filling amounts to 75 or 100 feet, and seems excess- 70 THE ILLINOIS GLACIAL LOBE. ive when compared with the amount of drift on neighljoring hills. On some of the hills between Rockwood and Park post-office, there is scarcely a trace of drift, though they are surrounded by the lowlands in which heavy deposits of drift occur. The drift continues thin on uplands as far north as Richland Creek, and the boundary is located with some difficulty. From the naiTows of Richland Creek, in sees. 8 and 9, T. 7 N., R. 4 W., northeastward to Newark, there is an exceptionally large amount of drift in the vicinity of the glacial boundary, both on uplands and on lowlands. Several exposures were found 200 feet above the creek, in Avhich there is not less than 50 feet of drift. The old course of Richland Creek, through a lowland tract east of Newark, has been filled up to a height of nearly 100 feet above the creek with deposits of sandy clay, carrying a liberal admix- tm-e of coarse rock material and an occasional bowlder. Siebenthal reports that in southeastern Owen County the drift is heavy in the valleys, but comparatively thin on the hills, and this feature is char- acteristic of the boundar}^ in Monroe County and southern ^Morgan Countv, as noted both by Siebenthal and by the writer. Small bowlders are present in moderate number in the ^sdcinity of the gdacial boundary in all these counties. CHARACTER OF THE OUTWASH. There appears to have been very little material carried out by water beyond the edge of this ice sheet except along the valleys. While the outer border plains and the small valleys heading in this di-ift margin occa- sionally bear thin deposits of sand and fine gravel which seem to be an outwash from the ice margin, there is nothing comparable to what is dis- played along some moraines of the Wisconsin stage described below. The best exposure of such an outwash yet noted is found near West Point, in Lee County, Iowa. About a mile northwest of the -sallage, imme- diately outside the lUinoian drift border, the following series of deposits is exposed in the gradings along an east-west road : Section near West Point, Iowa, shou-ing (/ravel oiiticu.^h. Feet. 1. Brown silt, apparently to be classed with the lowan loess 7 2. Fine gravel, ronsiilereil an outwash from the lUinoiau channel was excavated may have been frozen at the time of the Illinoian glaciation, its situation being on the immediate border of the ice sheet, and ' See Chamberlin : Third Ann. Rept. U. S. Geol. Sui-vey, p. 391. 94 THE ILLIJSOIS GLACIAL LOBE. the frozen condition of the ground may have prevented the stream from eroding more material than it could readily transport. In that case the material should be accumulated in portions of the Mississippi Valley to the south, where the gradient became too low to admit of its being swept along. In apparent support of this view there is found, immediately below the Des Moines or lower rapids of the Mississippi, a marked filling of the valley with deposits of sand and fine gravel. This filling may be seen to good advantage at and below the village of Warsaw, which stands on a terrace of aggradation antedating the loess in its formation and apparently sepa- rated from the Kansan glacial stage by an erosion interval of considerable length. The Warsaw exposures were examined by the writer in 1894 and reexamined by Professor Chamberlin, Dr. H. F. Bain, and the writer in the summer of 1896, when the relationships given above were worked out. The Kansan till has suffered erosion to a level but little above the present stream and a bowlder bed marks the junction of this till with the overlying sand and gravel. This bowlder bed is continued on the north side of the river in Keokuk, as pointed out by Prof C. H. Gordon.^ The sand and gravel deposits are typical fluvial material and are built up to a height of about 80 feet above the river. At their top is an ashy silt resembling a soil but perhaps redeposited as flood-plain material, and above this a deposit of sand grading upward into loess, the sand and loess together being 20 to 25 feet in thickness. Opposite Warsaw near the mouth of the Des Moines River there is a somewhat different exposure of fluvial filling known as the " Yellow banks." This has been examined, both by the writer and by Pro- fessor Gordon, and the following section was published in the Geology of Iowa in 1895:' " Yellow-banks" section, near Keokuk, loioa. Ft. in. Clay, yellow, pebbleless 5 Silt, drab, pebbleless 1 3 Eurtb, black, with a few small pebbles ; apparently an old flood-plaiu deposit .• 12 Chiy, yellowish (local) 6 Sand, with a few small pebbles; layers of bowlders 1 loot thick at base 20-25 Earth, bliick, with yellow streaks; apparently an old flood-plain deposit 3- 6 Gravel, with some sand beds ; pebbles 2 inches or less in diameter 20 Bine clay, till, exposed 15 Total 7 85 1 Iowa Gool. Survey, Vol. Ill, 1895, pp. 252-254. ' Op. cit., p. 243. >^^.,"- *.^' 96 THE ILLINOIS GLACIAL LOBE. deposits of sand and silt that seem referable to the valley filling at the lUinoian stage of glaciation and which antedate the loess by a long period, as shown by weathering. The surface of the sand presents a deep red stain to a depth of 3 or 4 feet below the base of the loess, and contrasts strongly in color and weathering with the sand at greater depth as well as with the overlying loess. The weathered zone here is apparently the cor- relative of the black earth found below the loess at the " Yellow banks." Excellent exposures of this weathered zone may be seen at the corner of Second and Tiniea streets in Keokuk. Examinations have been extended down the IMississippi on the Illinois side, and it is found that the altitude of the valley tilling decreases more rapidly than the fall of the present stream. At a point opposite Hannibal, ^Missouri, where Hadley Creek enters the valley from the east, the filling reaches a level only 15 or 20 feet above the broad bottom of the Mississippi or scarcely 35 feet above the stream, and about 90 feet below its altitude at Warsaw, 45 miles up the valley. This rapid increase in the amount of filling apparently supports the view that material was swept into the valley and there deposited in delta-like fashion. Returning to the discussion of the abandoned channel, and taking up the portion northeastward from the Iowa River, it is found that it has slightly lower altitude than the portion in the district south from the Iowa River, much of it being below 700 feet above tide. In explanation of this lower altitude it is suggested that the section to the north of the Wapsipin- icon River and possibly the portion between the Wapsipinicon and Iowa rivers may have been occupied by the Mississippi for a considerable period after the southern portion had been abandoned. Possibly it persisted in the occupancy of its channel until the lowan ice invasion forced it out. The broad valley of the southwestward flowing portion of the Cedar appears to have held a lake at the Illinoian stage of glaciation for which Udden has recently suggested the name "Lake Calvin." The features of this old lake bed are discussed by Udden in a report on the geology of Muscatine County, Iowa.' The abandonment of the lower end of the channel from Columbus Junction southward probably occurred as soon as the ice sheet had with- drawn sufficiently to uncover the present line of the stream, for the altitude I Iowa Geol. Survey, Vol. IX, 1899, pji. .Sr.O-KT. 1 a H -X :^? tiiiiiii!i!i;li 53 Or: -S 1 ^ ■ _ M ^ ^ > _i a. > X X X I Q. < tr o o z o UJ > DC =3 01 _! < o o o _l o UJ cri ri a. Q I O '' CD ?; o i CO 03 i/1 P O o CHANGES OF DEAINAGE IN SOUTHWESTERN INDIANA. 97 along the present Mississippi bluffs is a few feet lower than the bed of the abandoned channel. This lower. altitude along the Mississippi is due to the incomplete filling of the preglacial channel by drift. CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA. The lUinoian invasion produced important drainage modifications in southwestern Indiana, only a part of which have as yet been fully worked out. The present discussion aims to deal chiefly with the changes which have received the most careful attention. The discussion begins with streams in the southwest corner of Indiana. By reference to the map, PL VIII, it will be seen that the greater part of Posey County and adjacent portions of Vanderburg and Gibson counties are now drained westward into the Wabash through Big Creek. The South Fork leads almost du'ectly west from near Evansville in Vanderburg County to its junction with the North Fork in central Posey County. The North Fork leads northwest from northern Vanderburg across southwestern Gibson into Posey County, and there near the village of Cynthiana turns southwestward and maintains this course to the Wabash. It receives a tributary from the southeast near the crossing of the Peoria, Decatur and Evansville Railway, but no other tributary of importance enters above its junction with the East Fork. An examination of the head-water portion of the North Fork has brought to light decisive evidence that its preglacial line of discharge was westward into Black River and thence to the Wabash at a point 20 miles or more above the present mouth of the creek. A broad valley deeply filled with di-ift leads from Big Creek westward to Black River, passing just north of the village of Cynthiana. The aban- doned valley is nearly a mile in width, while the new passage is scarcely one-tenth of a mile in width. The creek soon enters another old valley whose head water portion is occupied by the southeastern tributary referred to above, but whose lower course is abandoned. The Peoria, Decatur and Evansville Railway utilizes the abandoned valley between Big Creek and Poseyville. From Poseyville the valley passes northwest to Black River. In the narrow valley near Cynthiana the present stream thus cuts across a low ridge separating two streams, which formerly drained northwestward into Black River. Below the railway crossing Big Creek soon enters a MON XXXVIII 7 98 THE ILLINOIS GLACIAL LOBE. narrow valley and crosses the preglacial divide between Black River and tlie Sonth Fork of Big- Creek. Thus the latter di-amage basin has been greatly enlarged at the expense of the former. The glacial boundary follows nearly the present course of the North Fork of Big Creek below Cynthiana, and the location of the new stream across the rock point near that village is e\adently due to the presence of the ice sheet in the lowlands to the west, and the diversion across the divide between the preglacial drainage basins of Black River and Big Creek is due to occupancy of the former by the ice sheet. The Pigeon Creek di-ainage basin has also been enlarged at the expense of Black River. Muddy Fork of Pigeon Creek lies in a lowland which connects on the southwest with Black River, and this lowland appar- ently received the portion of the Pigeon Creek drainage in Gibson and northern Warrick counties. The location of the col was not definitely worked out, though it is in all probability east of Elberfeld, in T. 4 S., R. 9 W. Upon referring the question of changes of drainage in the Pigeon Creek basin to Dr. George H. Ashley, of the Indiana survey, who has made an examination of the portion in Warrick County ouiside the limits of the writer's own examinations, the following reply was received:^ I think you are right in believing that the head waters of Pigeon Creek drained to the west in preglacial times, the divide running nearly east and west across the center of T. 4 S. through Es. 8, 9, and 10 W. The present course of Pigeon Creek through Ts. 4 and 5 S., E. 9 W., while not so markedly a postglacial channel as many to be found, has nevertheless several of the characters of such a channel. In the tirst place the bottoms are narrow, averaging probably less than one-half mile in width from above Elberfeld to below Millersburg, or scarcely half the usual width of the west-flowing head water portion. Secondly, the blufl's are more abrupt than is usual for streams of this size in -that region. This is especially true north of east from Elberfeld, where the stream appears to have crossed an old divide. Thirdly, the short tributaries on each side of the streams in the vicinity of the supposed divide also sustain this view. Fourthly, reports suggest that rock is to be found within a dozen feet below the stream bed in this narrow portion, but this has not as yet been verified. The changes of drainage become still more important in passing north- eastward into Pike and Dubois counties. The streams which fornaerly had a northwestward discharge into the White River drainage have been turned westward just outside the glacial boundary to form the Patoka River, as ' Letter written June 8, 1898. CHANGES OF DEAINAGE IN SOUTHWESTERN INDIANA. 99 may be seen by reference to the map, PI. VIII. These perhaps may be discussed to best advantage by beginning at the east with the head waters of the Patoka. The portion of the Patoka above Jasper seems to be following a preglacial line, but at that town a deflection of the stream into another drainage basin has been effected. The preglacial valley is easily traced from the Patoka, in sec. 24, T. 1 S., R. 5 AV., northwestward to Mill Creek Valley and thence into East White River. Its breadth is about IJ miles, and it has been filled with sand and loess-like silt to a height of 30 to 35 feet above the present level of Patoka River, in sec. 24, or to about 490. feet above tide. This filling was sufficient to turn the stream across a low divide in the east part of Jasper. In opening a passage across this divide the stream has accomplished a remarkably small amount of work. The naiTOw part of the valley which marks the position of the old divide is only about one-half mile in length, 600 to 800 feet in width, and 20 to 35 feet in depth. The stream is reported to be several feet in depth through this narrow portion, thus increasing the depth of erosion perhaps 10 feet. There is in part of the gorge a thick-bedded sandstone which has probabl)- greatly resisted lateral erosion. Immediately south of Jasper the present Patoka River enters a valley fully 1 mile in width which constitutes the preglacial line of discharge for several southern tributaries entering in Dubois County. The valley is not occupied far by the present stream, but leads from Jasper in a course north of west into Pike County, passing south of Ireland and directly imder the vil- lage of Otwell, its course for several miles being nearly coincident with Flat Creek, though in the reverse direction. Whether it joined the East White Valley near Highbanks or entered a few miles below, at the mouth of Mud, Creek, is undetermined. There are shallow valley-like depressions connect- ing the abandoned valley with East White River along each course which are underlain by heavy deposits of drift, each of which apparently has a width sufficient to have accommodated the old stream. Probably, however, one of these lines will be found to be separated from the old valley by a concealed rock barrier. This old valley, as above noted, has a rock floor considerably below the present bed of the neighboring portion of East White River, a boring at Otwell having failed to reach rock at a level about 35 feet below the river. 100 THE ILLINOIS GLACIAL LOBE. The present Patoka Kiver leads southward from Jasper for several miles, occupying the northern end of the broad valley of Hunleys Creek, a southern tributary of the abandoned valley just discussed. The river then takes a northwestward course, cutting- across a narrow neck of upland and touching- the border of the abandoned valley about 2 miles south of Ireland. In this passage across the neck of upland the width of the flood plain is nowhere less than one-fourth of a mile, or about double the width of the valley bottom in the gorge at Jasper. Whether this difference iia size is referable to variations in the texture of the rock or is due to difference in date of deflection has not been determined. It seems, however, not improb- able that this narrow neck had been encroached upon by valleys on each side and severed from the main upland prior to the glacial invasion. After touching the old valley near Ireland, the Patoka turns to the southwest and near the line of Dubois and Pike counties enters a narrow valley 800 to 1,000 feet in width. The narrow portion extends from the county line southwest about 2 miles to the mouth of Rocky Creek, a south- ern tributary. It there expands to twice or three times the Avidth of tlie narrow portion and from that point gradually increases in width down the stream, reaching nearly 2 miles in western Pike County. The narrow por- tion evidently marks the position of a preglacial divide. That this divide had been reduced to a low elevation is shown by neighboring cols, which, though low, were not utilized by this stream in selecting a new com'se. One of these cols at the village of Velpen stands only 510 feet above tide. It is probable that the blockaded stream had to rise no higher than 500 feet to cross the divide, or to a height of less than 75 feet above its present level; possibly the divide was not more than 475 feet at the col. The latter alti- tude is slightly lower than the sand and silt filling made by Lake Patoka which, as above noted, is found in the abandoned valleys to the north and east of this divide. This filling is conspicuous in the vicinity of the divide as well as above, and seems to pass down the present stream beyond the divide without appreciable decrease in altitude. The col was nearly if not quite covered by silt before the present channel was opened across it. The Patoka River apparently follows the line of a preglacial stream from tlie mouth of Rocky Creek, in eastern Pike County, westward iiito Gibson County to the bend about 6 miles above Patoka. It there is in a low tract which extends northward to White River. But instead of follow- CHANGES OF DRAINAGE IN SOUTHWESTERN INDIANA. 101 ing' this lowland it continues westward and passes through a range of hills which leads northward from Princeton past Patoka to White River at Hazel- ton. This deflection lies within the glaciated region and calls for a some- what different explanation from those just considered. It is probable that a lower passage was afforded across a col near Patoka than the lowland to the north else the stream would not have suffered this deflection. In the pas- sage through this range of hills at Patoka the A^alley is reduced to a width of scarcely one-half mile or to about one-fourth the width of the preglacial valley which it occupies a few miles to the east. Upon passing this range the stream soon enters the broad valley of the Wabash and takes a some- ■\vhat direct course into that river. Since Patoka Eiver enters the glaciated region in its lower course the question arises whether it found discharge beneath the ice margin during the time when its lower coiu'se was covered by the ice sheet or found a line or lines of discharge southward through the unglaciated region into the Ohio. There is a col on the divide between Patoka and Ohio rivers crossed by the abandoned Wabash and Ohio Canal about 1 mile southwest of Francisco, which stands only 480 feet above tide, or about the altitude of the silt deposits along the Patoka in western Dubois and Pike counties. From this col there is an open line into the head waters of Pigeon Creek. But as noted above there may have been another col in northern Warrick County on the present line of Pigeon Creel?: to offer resistance to the discharge of water to the Ohio. It is doubtful, however, if that col stood any higher than the one near Francisco, and it may have been so low as to afford an eas}' passage for the stream. An examination of the col near Francisco failed to bring to light decisive evidence that a stream had crossed it. The sag crossing the divide is scarcely 100 rods in width and is not bordered by banks or well-defined erosion contours. The features seem to be no differ- ent from those of other sags at higher altitudes on the divide. The canal cuts through about 12 feet of loesslike yellowish-brown earth before strik- ing the rock surface, which is similar to the material found on border dis- tricts at all altitudes. It seems less probable that cols on the Patoka-Ohio divide farther east were utilized, for they stand considerably higher than the col under consideration; the lowest stand probably about 525 to 550 feet above tide. The col crossed by the railway near Ferdinand station, 7 miles south of Huintingburg, is probably as low as any, standing 530 feet 102 THE ILLINOIS GLACIAL LOBE. above tide. The sag leading across this divide, hke that near Francisco, is too narrow to have suflPered much erosion l)y a stream discharging across it. On the whole the evidence of southward discharge into the Ohio seems very weak, and the view that the water which accumulated along the ice margin in Dubois and Pike counties found its main discharge to the Wabash under the ice margin, appears more probable. At most the col near Francisco appears to have served only temporarily as a waste weir for the accumulated waters. Several interesting deflections of small streams have been noted in the vicinity of the glacial boundary in the district lying between East White and the main White River. These have been brought to light by the studies of Mr. C. E. Siebenthal, of the Indiana geological survey, with perhaps one exception, that of Furse Creek in northwestern Martin County. Siebenthal has kindly furnished notes on these changes of drainage in advance of the pidolication of his report. Since receiving his notes the writer has had opportunity to examine some of the deflections brought to light by Siebenthal, but for the detailed examination, as well as the discovery of these deflections, Siebenthal should receive credit. It is scarcely probable that all the deflections have been brought to light, for the valle5's of some streams in Daviess County have not been given sufficient attention to wan-ant their discussion. The first deflection discussed is that of Furse Creek, after which the streams examined by Siebenthal are taken up in order from south to north. Furse Creek as shown in PI. IX, strikes the glacial boundary about 2 miles east from the west line of Martin County. It there turns abruptly southward and enters a gorge in the southeast part of sec. 8, T. 5 N., R. 4 W., in which the creek bluflPs border the stream closely on each side for a mile or more. The stream then enters an open valley formed by the small southern tributary which joins it in sec. 18. Whether it has suft'ered other deflections below this point has not been determined. From the point of deflection in sec. 8 a lowland tract heavily coated \\'ith drift leads north- . westward to the valley of Doans Creek, near Scotland. This probably was the preglacial line of discharge for Furse Creek. Siebenthal has found that Richland Creek was deflected southward near the point where it strikes the glacial boundary li miles east of the village of Newark, its old course ha\'ing been northwestward from that point. The position of the col on the old divide below the point of deflec- tion of the creek is clearly shown in a view from a hill southeast of Newark. >< _i > X X X I a < o o UJ > cc (!) < o o o _] o Ul CO !::; ° S en rt -r: 3 ct 2 o S 3 q m n rt aj 2 P ' ■So o .15 ■■?, g55 ^ a - o ^ « « ? « IS.?" ^" '5 L- ^CT)^ O ^ ^ K § 5 S 1/; J Z Ld O UJ > X X X I Q. < o o > a: ID U) _1 < o o o _] o UJ o en si 1 9 ■■ do, S3 H 2 ■ ' J ^ or 1—1 CHANGES OF DRAINAGE IN SOUTHWESTEKN INDIANA. 103 The bluffs close in on either side of the creek near the center of sec. 19, sloping gradually to the border of the stream. The stream has cut a notch nearly 100 feet in depth across the col. It soon enters a small preglacial valley, but appears to follow the course of that valley for only a short dis- tance. Its course for about 8 miles is mainly across rock points and low divides and lies just outside the glacial boundary. At its junction with Beech Creek a preglacial valley is found, but tlie stream turns out of this valley in sec. 9, T. 7, R. 4 W., and takes a direct course westward through a gorge, thus cutting off a rock point on the south side of the preglacial Beech Creek Valley. It reenters the old valley near the corners of sees. 7, 8, 17, and 18, after traversing a gorge for about IJ miles, and is reported by Siebenthal to continue in a preglacial valley to its mouth. The stream lies within the glaciated region throughou.t the portion below the mouth of Beech Creek, but is only about 5 miles by direct line inside the glacial boundary at its entrance into White River. It seems probable that the stream discharged through the low glaciated districts bordering White River, even at the maximum extension of the ice, for no line of dis- charge is found across the elevated districts outside the glacial boundary: In the head-water portion of Richland Creek, above the point of deflec- tion from its preglacial valley, there appears to have been a glacial lake for which Siebenthal has proposed the name Lake Richland. The presence of the lake is shown by terraces and deposits of silt and sand which filled ' the valley up to a definite level. They stand nearly 100 feet above the creek at the point of deflection, but in passing up the valley they gradually approach the creek level, being but 30 or 40 feet above the stream in the vicinity of Whitehall. Whether they are perfectly horizontal has not been determined. The lake apparently extended up the creek a short distance into Monroe County. About 4 miles south from the point where Richland Creek turns west- ward into the glaciated district the glacial boundary comes to the west end of another glacial lake whose site is now known as the "American bottom." It extends eastward about 5 miles from the glacial boundary and has an average width of nearly 1 mile. This old lake bottom now has subterra- nean di-ainage southwestward through sand deposits to a tributary of Clifty Creek, where it appears in the form of springs. Because of the subterranean drainage the plain is preserved in nearly the condition left by the lake. 104 THE ILLINOIS GLACIAL LOBE. Passing uortln\'ard iuto Owen County there is found a slight detlection in Raccoon Creek, just inside the glacial boundary. Instead of following its old course the creek glasses across a rock point on the south, occupying a gorge for about a mile. The head-water tributaries of Raccoon Creek outside the glacial boundary caiTy terraces of silt and sand which are inter- preted by Siebenthal to be the accumulations made in small glacial lakes held in front of the ice sheet. The "Flat Woods" of eastern Owen and western Monroe counties cover an area of several square miles of elevated land, immediately inside the glacial boundary. The flats in this area are interrupted by hilly tracts, and the entire area is above the general level of border tracts. These features are thought to indicate that no large stream occupied the "Flat Woods" in preglacial times. It is suggested by Siebenthal that the region had a system of subterranean drainage prior to the glacial invasion, but that glacial accumulations have caused a change to surface drainage.^ The flats are now di-ained chiefly to the north through McCormack's Creek. The western portion drains westward through Ellison's Branch into White River. On McCormack's Creek there is a fall about a mile from its mouth, above which there is only a shallow, poorly drained valley. The main work of the stream since the Grlacial period has been given to the exca^-a- tion of the gorge below the fall, but no accurate estimate was made of the work accomplished in cutting back to the fall. The eff"ect of the ice invasion upon the course of White River has been even greater than on the small eastern tributaries which enter it from the unglaciated region. The preglacial drainage is so greatly concealed above the north line of Greene County tlaat it seems impracticable to determine even the course of the main drainage line. The stream is now occupying a preglacial valle}' for a few miles in southwestern Morgan County, and is also in a preglacial valley throughout much of its course below Owen County. But in its passage across Owen County it is opening a new val- ley. It has been suggested that this stream had a subterranean passage across the sink-hole region of Owen County, in which case no well-defined suiiace channel may have been opened prior to the glacial invasion. The available data sociii insulHcicnt to t(^st the applioabilitv of this interpretation. 'Tweuty-first Aun. Rept. ludiana Geol. Survey, 1896, pp. 301, 302. EELATIOKS OF THE ILLINOIAN DRIFT SHEET. 105 PLEISTOCENE DEPOSITS BEISHEATH THE lELI^TOIA^T TILL SHEET. Although the Illinoian till sheet throughout much of the region under discussion may rest immediately on the rock, there are, in places, deposits separating it from the rock formations. The deposits are principally of two classes — namely, the Kansan till, Avith perhaps a somewhat distinct pre- Illinoian till, and vallej'' silts or sands. KANSAN TILL. Attention has been called to the till of southeastern Iowa and western Illinois, which underlies the Illinoian drift and which is referred to the Kansan. The full extent of this sheet of till in western Illinois is not determined. Its eastern border comes to the Mississippi Valley from the south near Hannibal, Missouri, and it probably continues northward into Illinois across Adams and Hancock counties. It probably also extends into counties east of the Mississippi farther north, although this has not been so clearly determined. That it extended into western Adams and Hancock counties is shown by at least two lines of evidence. The first line of eAddence is that furnished by striation. An exposure of a striated ledge with a bearing S. 65° E. appears on the south side of Wagner's Creek, about 4 miles above Hamilton, Illinois, and 2 miles east of the Mississippi. This, so far as known, is the only instance yet discovered of striation produced by the Keewatin ice field east of the Mississippi and south of the Wisconsin Driftless Area. The striae reported above in the vicinity of Burling-ton, Iowa, are in some cases situated on the brow of the west bluff of the Mississippi, showing that the eastward movement extended at least to the Mississippi Valley. The second line of evidence of the extension of the Keewatin ice sheet into western Illinois is furnished by till deposits separated from the over- lying Illinoian by a soil and carrying other evidences of greater age than the Illinoian. In the discussion of the border of the Illinoian di'ift in Han- cock and Adams counties, Illinois, attention was called to the occm-rence of a heavy sheet of blue till similar in structure to that found beneath the Illinoian west of the Mississippi, and to a few exposures near the line of Hancock and Adams counties of a black soil separating the till from the overlying Illinoian. In these exposures it was found that the till under the 106 THE ILLINOIS GLACIAL LOBE. soil had been leached to a depth of several feet, a feature which testifies to the lapse of a considerable period between the deposition of the two till sheets. This black soil between the tills is also penetrated in wells in western Hancock County. A possible third line of evidence of the extension of the Keewatin ice sheet into western Illinois is found in the presence of laminated clays in a buried preglacial valley in central Adams County. These clays ai"e con- jectured to be due to an obstruction of the lower course of the valley in western Adams County by the Keewatin ice sheet. The obstruction might have formed a lake in which these deposits were laid down contempora- neously with Kansan till. The lapse of a long interval between the deposition of the Kansan till and the Illinoian is clearly shown in southeastern Iowa, not only by the presence of a soil and leached subsoil between two sheets, but by the markedly greater erosion of the Kansan than of the Illinoian sheet. This erosion is manifest to the trained observer on passing from one sheet to the other. In the district occupied by the Kansan the erosion is so great that only narrow remnants of the original diift plain are preserved along the water partings. But in the district occupied by the Illinoian more than half the original drift plain is preserved, and that, too, on the immediate borders of the Mississippi, where conditions for erosion are more favorable tlian in the area to the west which is occupied by the eroded Kansan sheet. The great contrast in amount of erosion supports strongly the view that a longer interval elapsed between the Kansan and lUinoian glaciations than between the Illinoian and the present time. Attention is called, in the discussion of the Illinoian drift border, to an instance of its filling a valley in Des Moines County, Iowa, that had been cut in the Kansan drift. This valley apparently had a depth of 50 feet beh.»w the bordering plains, but no data are available concerning its width. It appears fi-om a study of the ten-aces on valleys cut in the Kansan drift of southeastern Iowa, that the erosion in the interval between the Kansan and Illinoian stages of glaciation was such as to form broad shallow vallej's rather than nan-ow deep ones. The large valleys appear to have been cut to a depth of but oO or 60 feet, though they had a width of one or two miles. PLEISTOCENE DEPOSITS BENEATH TILL SHEET. 107 PRE-ILLINOIAN (?) TILL AND ASSOCIATED DEPOSITS. As yet the evidence pointing toward the occurrence of drift of greater age than the IlHnoian in the districts to the east, which lie beyond the hniits of the Keewatin ice* sheet, has not sufficient strength to make it seem advisable to advocate a pre-Illinoian till. There are occasional well sections reported to have passed through a bed of wood or of soil in the midst of the till in central Illinois. Thus at Pana a section reported by Worthen is as follows:^ Section of well at Pana, Illinois. Feet. Soil and clay 11 Blue clay 4 Sand and gravel 12 Hard red clay 18 Forest bed 3| Blue clay : 57 Black soil or forest bed 2| Blue clay 19 Total 127 This section is based upon specimens preserved from a test boring with diamond drill. The specimens were recently examined by the writer and some light obtained concerning the interpretation to be put upon this sec- tion. The upper 15 feet consists of a pebbleless material to be classified with the loess. The upper forest bed proves to be simply fragments of wood embedded in ordinary till. The till was found to be very calcareous at the horizon of this wood and to show no evidence of atmospheric expo- sure subsequent to its deposition. The wood appears, therefore, to be simply material deposited in the till by the ice sheet and has no more si^-nifi- cance in determining a time interval than the presence of a Paleozoic fossil embedded in the drift. The lower forest bed consists of a humus-stained clay in which fragments of wood occur; it is apparently a soil. Under it is a greenish clay subsoil, such as occurs beneath swamps. This, as well as the soil, is pebbleless. At the bottom of the clay, resting on the limestone rock, there is a thin bed of ferruginous conglomerate, in which angular chert is mingled with waterworn pebbles. No Canadian rocks or specimens which can be referred to glacial action were found. This raises the question whether the conglomerate is not of preglacial age. The soil 1 Geol. Illinois, Vol. VII, pp. 22-23; also Vol. VIII, p. 15. 108 THE ILLINOIS GLACIAL LOBE. at the base of the drift, together with the underlying subsoil, appears to be connected but remotely at least with glacial agencies. The de230sit appar- ently antedated the deposition of the overlying till by a considerable interval. The writer is inclined to refer to the Illinoian invasion the series of clays setting in at 27 feet and extending- to 106 feet. Worthen reports a section at Virginia, Illinois, in which a black soil appears between tills at a depth of 67 to 70 feet.' On making inquiry of Dr. J. F. Snj-der, of Virginia, concerning this section, it is found that the recoi'd of the coal shaft on which Worthen based his section of the di-ift was not kept with a sufficient degree of accuracy to insure its correctness. Dr. Snyder is of opinion that the distance to rock is about 70 feet greater than shown by this record. It would certainly be hazardous to base an important time interval on the reported occurrence of soil in the shaft at Virginia. The section of a coal shaft at Bloomington reported by Dr. H. M. Banister^ represents the occurrence of two buried soils. The section as reported by Dr. Banister is as follows : Section of coal shaft at Bloomington, Illinois. Veet. Surface soil and Ijrown clay 10 Blue clay 40 Gravelly hard pan 60 Black mold with pieces of wood 13 Hardpan and clay 89 Black mold, etc 6 Blue clay 34 Quicksand, buifaud drab in color, and containing- fossil shells 2 Total drift 254 In this section the upper 11 U feet may be referred with considerable confidence to the Wisconsin drift. The upper "black mold" at 110 to 123 feet was apparently post-lllinoian. It is probable that the Illinoian sheet is represented in the "liardpan and cla}-" at 123 to 212 feet. The remainder of the section would be therefore pre-IUinoian. Whether the blue clay Ijelow tlie lower "black mold" is a glacial deposit is not clearly shown. It ma}- pnn-e to be a water deposit. In view of this uncertainty it seems unsafe to use this section as evidence for the occurrence of a pre- IlliiKiiaii (h-ift slieet in central Illinois. ' Op. cit., Vol. Vm, p. 16. ■' Op. cit., Vol. IV, 1870, p. 178. Also Vol. VIII, p. 14. PEE-ILLINOIAN (?) TILL AND ASSOCIATED DEPOSITS. 109 lu this connection attention is called again to the section of a shaft at Coatsburg, in Adams County, in which a laminated clay of considerable depth underlies the till, but which is not a strictly glacial deposit. The Bloomington section may be of similar character in its lower portion. The sections above discussed comjjrise the most puzzling ones reported in the geology of Illinois. The buried soils there reported are usually found, when in the district outside the Wisconsin drift, either at the base of the loess, which is a post-Tllinoian interval (Sangamon), or at the bottom of the glacial deposits, where only silt or sand occurs between the soil and the underlying rock. Prof. R. D. Salisbury has reported the occurrence of two sheets of drift in southeastern Illmois and southwestern Indiana. He considers them representatives of two episodes of a single glacial epoch. The upper sheet is thought to extend fully as far as the lower, if not beyond it.^ As the features referred to by Salisbury have never been investigated by the writer, some hesitancy is felt in offering an interpretation. It is, however, suggested that the invasion limited on the southwest by the ridged drift of the Kaskaskia Basin may have formed the upper sheet, while the invasion, which in southwestern Illinois was the more extensive one, may have formed the lower sheet. Possibly the interval will prove to be too long to supjDort this interpretation. In that case the lower sheet would be referable to a pre-Illinoian invasion. In northern Illinois there are certain deposits which need consideration in this connection. The studies of Mr. Ira M. Buell in eastern Winnebago County led to the discovery of several exposures of g'lacial conglomerate which appear along the east bluff of Pock River. Bowlder-like masses of this conglomerate have been incorporated in the till of that region, a good illustration being found in the cuttings of the Illinois Central Railroad, immediately southeast of Rockford. The firm cementation, and also a deep orange-colored stain presented by the conglomerate from which these bowlders are derived, seems to have been produced prior to the deposition of the sheet of till in which they are embedded. This till is probably of lowan age. It therefore remains to be determined whether the conglom- erate is of lUinoian age or of still earlier date. There are other deposits in this region, noted by Buell, which favor the view that there were not 1 See Arkansas Geol. Survey, Crowleys Ridge, Report for 1889, Vol. II, p. 229. 110 THE ILLINOIS GLACIAL LOBE. less than two ice invasions prior to the lowan. Reference is made to the evidence fonnd in the occurrence or distribution of bowlders of Waterloo quartzite, a subject Avhich has been investigated in considerable detail by Buell and discussed in a recent paper published in the Transactions of the Wisconsin Academy of Sciences.^ The earliest movement affecting the ledges of Waterloo quartzite, which has been recognized by Buell, is interpreted by him to have been westward. This movement is indicated by the westward transportation of bowlders from the quartzite ledges, and farther south by the occurreiice in the marginal portion of the drift of Devonian and Upper Silurian rocks, which could only have been derived from the east. Following the westward movement, he thinks there is evidence of a southward movement, through which quartzite bowlders were carried into northern Illinois. He considers the western margin of the ice lobe which transported this material to be indicated by a " belt of thickened stony till and kame-like gravel deposits, the fonner appearing on tlie ridge surfaces and the latter spreading over the lower level." This supposed line of marginal deposit has been traced by Buell from the point where it emerges from beneath the Kettle moraine, near the line of Dane and Greene counties, Wisconsin, southward through eastern Greene County, Wisconsin, into northeastern Stephenson County, Illinois. Quartzite bowlders have been discovered in this belt and over the countr}" to the east to points slightly beyond Rock River, but none were found by Buell west of this belt. They are readily found as far south as the latitude of Freeport and Rockford, but farther south they are very rare, and apparently represented only by small fragments. Buell thinks it probable that the southward movement extended but little beyond a line connecting these cities, the scattering pebbles to the south being transported perhaps by water. The southward movement is thought to have been followed b)' a southwestward one in southern Wisconsin, with perhaps westward movement in southern Illinois, by which quartzite bowlders -wei-e carried southwest fi-om the ledges slightly beyond the limits of the Kettle moraine. Tliis invasion is referred to the lowan stage of glaciation by Buell, and is correlated by him witli the main loess deposition. He limits its western extension to the east border of the loess. The interpretation made by Buell would refer the earliest or westward ' Bowlder tmins from the outcrop of thu Watoiloo i|uartzite area, by Irii M. Bnell : Trans. Wis- cousiu Aiad. Sci., Vol. X, 1891-95, pp. 405-o0!l. SILVERIA (t) FORMATION AND OTHER SILT DEPOSITS. HI movement to the Illinoian stage, while the southward movement is interpo- lated between the Illinoian and lowan. If, therefore, this interpretation be correct, it affords no evidence of a pre-IUinoian invasion. The subject of bowlder transportation has been studied so little as yet that it may be unsafe to take the interpretation given by Buell as fiiaal, although it appears well sustained. On this question, as well as on that of the age of the con- glomerate found on the borders of Rock River, further light is desirable. Hershey has recently discussed certain silts in northwestern Illinois, which underlie the Illinoian drift, as probable representatives of a stage of glaciation preceding the Illinoian.^ He does not, however, refer the silt deposition to a time much earlier than the Illinoian.^ There is evidence of erosion of this silt prior to the ice invasion which deposited the Illinoian drift. It is possible that these silts may be correlated with the ferruginous glacial conglomerate along the east side of Rock River, the conglomerate being deposited by a stream and the silts by a temporary lake, though there is as yet no adequate basis for such a correlation. SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. In the course of the discussion of the Illinoian drift and of the Kansan till sheet, which it overlaps on the west, frequent reference has been made to the occurrence of deposits of silt beneath the Illinoian. These deposits are known to be distributed very widely beneath the Illinoian drift, but it is not known how large a combined area they cover. They appear to be present in conspicuous amount beneath many streams of northwestern Illi- nois, but are not often exposed to view because of their position beneath the level of the streams. They appear to be less extensively developed in western and southern Illinois, though not rare in either district. Their best development, so far as known, is along the line of valleys which were favorably situated for the development of lakes in front of the ice, A'-alleys whose lower coiu'ses were entered by the ice sheet, while their upper courses remained for some time uncovered by the ice. Hershey has proposed the name Silveria for deposits of this class in northwestern Illinois.^ The necessity for a name for such deposits will 'Am. Jour. Sei., 4tli ser., 1896, Vol. II, pp. 324-330. -As Hershey uses the word Kansan for the sheet which we are discussing as the Illinoian, the reader may find it somewhat confusing to interpret his language. Hershey, however, is not at fault in the use of this term, since his paper was prepared before the uame Illinoian had l)een introduced. He naturally inferred, in the absence of knowledge to the contrary, that the same name should be applied to the sheet outside the lowan in northwestern Illinois as has been applied in southern Iowa. 112 THE ILLINOIS GLACIAL LOBE. depend upon the bearing they may have upon glacial history and then- relation to each other. Should it be found that any of them bear evidence of a distuict stage of glaciation to which no name has yet been applied, or to auA' part of geological time not assigned a name, it would seem proper to inti-oduce a name. But if they simpl)^ mark the deposits of small lakes of temporary character formed during an ice advance to which a name has already been applied, it Avould seem better to extend the name of the ice invasion to the silts. Thus we might speak of bm-ied silts of Kansan age or of Illinoian age. The relation to the glacial deposits would then be more clearly seen than if a separate name were applied to the silts. In the case of the silts which Hershey has named Silveria there appears to be evidence that thej^ do not connect definitely with the advancing Illinois ice lobe, for, as noted above, they seem to have suffered some erosion prior to the Illinoian ice invasion. It therefore may be necessary to retain the ~ - "^'^ ^i^^ga^Qgg^'^'*^'''^^^"'^^^^^^'^'' -^-^^^^^ ^^&^'-"'-'~' ^— ^^^^^^Zj^ :j-- a, Present. soil. /', Loes.s. c, <3td soil. rf.TilldlliLoian). e. Chert, etc. /, Extr.i-glaci.ll silt. y, Brown s.ind. FKi. 1. — Section showing tlie ' Silveria fonutttiou " near Freeport, Illinois ; prepareil by O.scar H. Hershey. a and * com- l)ine(l are the *' Silveria. " name Silveria, but to restrict it to deposits which are clearly of similar age to those examined by Hershey. If, on examining the silts of valleys in other parts of the region covered by the Illinois lobe, it is found that a similar interval of erosion separates their dei^osition from tluit of the Illi- noian drift, the name may be extended perhaps to such deposits. But if it is found that valleys contain silt deposits which immediately precede the Illinoian till sheet in date of deposition, it seems advisable to withhold the name Silveiia and refer to them as the silts of the Illinoian stage. It is probaljle that many if not all the valleys in which the Illinoian till sheet blocked tlie lower course and formed the temporary lakes contain deposits of this latter class. It is likely, therefore, to be more extensive than the Silveria formation. Hershey recognized this restricted application of the name, and gives the extraglacial silts a separate place (see fig. 1). In western Illinois, as was indicated above, there are silts which appear SILVERIA (?) FORMATION AXD OTHER SILT DEPOSITS. 113 to nave been formed at the Kansau stage of glaciation by the blocking of valleys which had westward discharge to the Mississippi. If this be the correct interpretation, these silts can not properly be termed Silveria, for they may be mncli older than that formation and their relation to the Glacial series would be more clear if they were termed Kansan silts. The Silveria formation discussed by Hershey "is a thick bed of strati- fied silt of a nearly uniformly dark bluish-gray color with bands often several feet in thickness which are a lighter tint." But one surface exposure has been found, and is located in a small ravine IJ miles south of the city of Freeport, yet wells have shown its occurrence in the valleys of nearly all the streams in the Pecatonica di'ainage basin. At the surface exposure "the upper portion is a false-bedded, calcareous and ferruginous, light- brown fine sand and silt, and appears to represent the shore deposits of an ancient lake in which this formation was apparently laid down." Its calcareousness strongly supports the view that it is a glacial silt. Several species of sirtail shells and also fragments of partially decayed wood have been collected by Mr. Hershey. Specimens of the shells, submitted to Dr. W. H. Dall, of the United States Geological Survey, are found to represent three difiPerent species, with fragments of still other species. These species are present in about the following proportionate numbers: Succinea avara 50, Pupa hlandi 5, Fyramidula striatella 2. Hershey refers the occurrence of this terrestrial fauna in a deposit of lacustrine character, to the position near the shore of the lake. This deposit appears to Have considerable bulk in the valleys of Stephenson County. In a well 3 miles southwest of Freeport, in the old valley of Yellow Creek, it was penetrated to a depth of 150 feet without reaching the bottom. Hershey estimates that if spread out over the entire surface of Stephenson County, this deposit would make a uniform layer at least 14 feet in depth. He estimates the total depth of the superficial deposits of Stephenson County to be 32^ feet. It forms therefore nearly half the bulk of these deposits. Above the silt which Hershey has called the Silveria formation there is another silt deposit separated from it by an erosion unconformity and a slightly developed soil. This he considers an extraglacial lake deposit formed during the advance of the ice sheet which formed the overlying till. This deposit he estimates to have an average thickness, if spread over the MON xxxviii 8 114 THE ILLINOIS GLACIAL LOBE. entire surface of Stephenson County, of but 1 foot, or only one-fom-teenth the bulk of the Silveria formation. In the vicinity of Rock Island several exposures of silt have been found by Prof. J. A. Udden beneath the lowest deposit of till, and through his kindness the writer has been conducted to them. Whether these deposits are all of similar age, and whether they are earlier or later than the Kansan, has not been determined. They appear to be at least as old as the maximum extension of the Illinoian sheet. One of the best exposures is that made b}^ a well at the base of the Mississippi bluff, near Thirty-sixth street, in Rock Island. The bluff back of the well carries about 40 feet of loess and several feet of till above the level of the well mouth. The exposures are not adequate to show the age of the till, though it is probably Illinoian. The section of the well, which was observed while in process of excavation both by Professor Udden and by the writer, is as follows : Section of well near Thirty-sixth street, BocTc Island, Illinois, Feet. Yellow till (probalily Illinoian) 5 Black muck (Yarmouth ?) 1 Brown till (leached 2 or 3 feet) 7 Blue till (probably Kansan) 4 Black calcareous silt, with gasteropod fossils 8 Black muck 4 Green muck with a few local pebbles 5 Coal Measures shale. Total 34 Within a mile east from this exposure, in the city of Moline, a well observed by Udden reached a fossiliferous loess-like silt beneath a pebbly clay at a depth of 30 feet. The well is on the Mississippi River bottom, corner of Seventh avenue and Fifth street, Moline, at an altitude about 30 feet above the low-water mark of the river. A ravine on the range line between sec. 7, T. 17 N., R. 1 W., and sec. 12, T. 17 N., R. 2 W., exposes the following section: Section of ravine on ranr/e line between sec. 7, T. 17 N., R. 1 W., and sec. 12, T. 17 N., R. 2 W. Peet. Loess 45 Black soil 2 Yellowish-brown till 12 Lopss-like silt, containing fossils several feet Coal Measures sandstone. SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. 115 Another exposure occurs in the east bkiff of the Mississippi near the line of Rock Island and Mercer counties and has the following section: Section of ravine near the line of Rock Island and Mercer counties, Illinois. Teet. Loess 25 Black soil 2-3 Till, mainly of blue color 90 Loess-like silt, very fossiliferous 12 Total 130 The bottom of the lower loess was not reached by this ravine. This deposit differs from the surface loess in containing a large number of nodules and tubes of partially solidified material. These have a yellowish color and are largely due to the presence of iron oxide. Specimens of fossils have been collected by Udden from these bm-ied loess-like silts in Rock Island County as well as from surface loess and submitted to Dr. W. H. Dall and his assistant, Mr. C. T. Simpson, for examination. The buried silt deposits are found to contain a larger pro- portion of Helicina occulta than the surface loess and a smaller proportion of Succinea avara. These two species are the most abundant ones in all the deposits, whether surface loess or buried silt. With the exception of the exposure of the east bluff of the Mississippi, the only additional fossils found in the buried silt are Pyra/michda striatella and Piqm aUicola. The latter species is now confined to the Rocky Mountain region. The speci- mens collected from the ravine in the east bluff of the Mississippi, near the line of Rock Island and Mercer counties, contain a greater variety, as follows : Helicina occulta Say; very abundant. Helicodiscus lineatus Say. Limnrea humilis Say (variety). Pyramidula perspectiva Say. Pyramidula striatella Anth. Pupa armifera Say. Strobilops labyrinthica Say. Succinea avara Say; less abundant than in surface loess. Succinea luteola Gould. Vitrea arborea Say ? The origin and relations of the buried loess-like silts of Rock Island County remain to be determined. Whether they are the deposit of an 116 THE ILLINOIS GLACIAL LOBE. extraglacial lake formed in valleys in front of tlie advancing ice sheet, or, like the svxrface loess, have a wider distribution less clearl}'^ connected with the ice invasion, is not at present known. They may be widely distributed beneath the Illinoian sheet in western Illinois. In texture and general appearance these deposits are very similar to the sm-face loess. They are- apparently not so compact as the laminated silts of northwestern Illinois, described by Hershey under the name Silveria formation. The deposits of laminated clay with sand partings, found beneath the till in central Adams County, Illinois, have akeady been discussed as prob- able products of an obstruction of an eastern tributary of the Mississippi by the Kansan invasion of the Keewatin ice sheet. It is probable that similar deposits fill the valleys of other eastern tributaries of the Mississippi in western Illinois, though as yet none have been observed. The date of these laminated clays, compared with that of the buried silt of Rock Island County, or of the Silveria forma,tion of Stephenson County, is not known. The silt beneath the till at Pana, noted above, is so much older than the overlying till that it can scarcely be considered an extraglacial lacustrine deposit formed during the ice advance which deposited the till. Its origin and date are not determined. In the reports of the geology of Illinois there appear several instances of the occurrence of a plastic blue clay, or "blue mud," below the till in the vicinity of the glacial boundary in southern Illinois.^ This blue material appears to be a silt deposit stained by humus. It often contains much wood and other organic matter. The writer has not been successful in finding an exposure and can not pass an opinion upon the character or the origin of the deposit. It is probable that valleys in that region which were obstructed by the advancing ice sheet were filled to some extent by silt, but since the deposit in question contains wood and other ^'egetal material it apparently antedated the till by a considerable interval, though it is possible that the accumulation of wood and organic matter is due to the introduction of this material by currents of water during the silt deposition, and not by the gi'owth of vegetation on the silt after the completion of the deposition. A detailed section of the material penetrated by the Isabella Thompson I Gool. Illinois, Vol. I, pp. 299, 300, 31G ; Vol. Ill, pp. 75, 86, 87, 103. SILVERIA (?) FORMATION AND OTHER SILT DEPOSITS. H? coal shaft near Sparta in eastern Randolph County, has been published by Prof. J. M. Nickles.^ The Pleistocene deposits are as follows: Section of Pleistocene beds penetrated by the Isabella Thompson coal shaft near Sparta, Illinois. Feet. Soil and clay 3 Yellow clay 17 Blue clay ^.. 3 Quicksanil 4 Silt 2 Gravel 4 Silt • — : 3^ Sand and gravel 6i Drab or mouse-colored silt 11 Concrete or bardpan 4 Fine giay sand 6 Sand and clay mixed 6^ Silt 2i Bowlder clay 6i Fine gravel 4 Bowlder clay If Laminated clay, containing wood 5 Tufcil drift 90 In this section there appears to have been an alternation of glacial and lacustrine deposition without distinct evidence of long interruption. The laminated clay at the base of the series contains a large amount of wood, specimens of which have been sent to the writer by Professor Nickles, but which await specific identification. Borings for coal and water in the Big Muddy Valley in the vicinity of Murphysboro usually penetrate a large amount of sand. As this valley does not appear to have been obstructed by the ice invasion the sand can not be referred with any certainty to lacustrine conditions. It seems more probable that it is an indicator of the weakness of the currents of the stream. The tributaries of the Wabash in southeastern Illinois are usually filled with sand or silt, and these open southward in such manner as to avoid obstruction by the advancing ice sheet. The filling probably may be taken as an index of the weakness of the currents of the stream just before the ice invasion. It may be remarked in this connection that the filling of the valleys of southern Illinois apparently opposes the somewhat popular hypothesis that there was a period of high elevation and vigorous ' Final report Illinois Board World's Fair Commissioners, 1893, pp. 200, 201. 118 THE ILLINOIS GLACIAL LOBE. stream action iu this part of the Mississippi Basin just before the first ice invasion. The character of the deposits beneath the till in the valleys of south- western Indiana has not received attention, for that region has been given only a hasty reconnaissance. The Wabash Valley is filled to considerable depth with sand and fine gravel, but this rnay be in large part derived fi-om the Wisconsin glacial drainage. Its rock floor stands 75 to 100 feet below the present stream at the points where tested by borings. The tributaries show a coiTespondingly low rock floor, but their filling in the district outside the Wisconsin diift is not so coarse as that along the Wabash. CHAPTER V. THE YARMOUTH SOIL AND WEATHERED ZONE. The occurrence of a definite soil and weathered zone between the over- lapping portions of the lUinoian and Kansan till sheets has been so fully set forth in the discussion of the Illinoian drift border that but few further remarks seem necessary. The name Yarmouth, as above indicated, is from the village in Des Moines County, Iowa, where the evidence of a prolonged interval between the till sheets, now known as Kansan and Illinoian, was first recognized. It remains to be determined whether the occasional instances of soil reported to occur between sheets of till in portions of the Illinoian area east of the limits of the Keewatin ice sheet are to be referred to the Yarmouth interglacial stage. Further light is also necessary to determine whether all instances of buried soils within the region of overlap of Illinoian upon Kansan till are to be referred to the Yarmouth stage. For example, the buried soil in the gas belt west of Letts may prove to be of earlier date than the Yarmouth, though it seems quite probable, as above noted, that it is found in a valley which had been cut in the Kansan drift prior to the Illinoian invasion. WEATHERING OF THE BURIED KAKSAIST DRIFT. Among the several evidences of a long interval between the Kansan and Illinoian invasion, that of weathering is the most common and perhaps the most decisive. As shown in the sections given above, there is found to have been a general leaching of the sheet of calcareous Kansan till to a depth of 4 to 6 feet prior to the deposition of the Illinoian sheet of drift. Accompanying the leaching the upper portion of the Kansan drift was weathered to a brown and in places reddish-brown color. The brown color extends much below the limits of the leaching, there being not a few instances in which it extends to a depth of 25 or 30 feet, and it is rarely less than 12 to 15 feet. The reddish-brown stain usually extends only to a depth of 2 119 120 THE ILLINOIS GLACIAL LOBE. or 3 feet from the surface. • The Kansau till, as noted above, is commonly characterized by vertical fissures and shows a tendency to fracture in rec- taug'ular blocks. Along the lines of the fissures the brown stain often extends some distance into the blue or unoxidized portion of the sheet, thus extending the limits of oxidation still lower than the general zone of oxida- tion. As ]3reviously stated, the amount of leaching and oxidation at the Yarmouth stage appears to be about as great as in all post-Illinoian time. There are, as above noted, places where the lUinoian till rests directly upon an unleached Kansau, but in such places the oxidation and vertical Assuring are present to testify to the changes effected in the Kansan sheet. The absence of a leached zone at the top of the Kansan in such places is readily accounted for through removal by the Illinoian ice sheet. It is perhaps more remarkable that the leached zone is so well preserved than that it should have been occasionally i-emoved by the Illinoian ice invasion. BURIED SOIL, PEAT, ETC. The accumulation of beds of peat at the surface of the Kansan drift, prior to the Illinoian ice invasion, constitutes as impressive an evidence of a prolonged interval as the leached and reddened surface. In the Yarmouth section the peat has a depth of 15 feet while underlying beds of sandy clay, and sand carrying bits of wood, probably also to be classified as inter- glacial, extend the depth of the Yarmouth deposits to 43 feet. Buried soil of black color and beds of peat have attracted the attention of well diggers in nearly every township of the region of overlap in southeastern Iowa, and specimens of the peat obtained from wells are preserved at many of the farm houses. Along the border of the Illinoian the soil is usually found at about the general level of the upland portion of the Kansan drift surface and may be referred with confidence to the Yarmouth stage, but occa- sionally it occurs below that level. In such instances, so far as the writer is aware, no soil has been noted at a level corresponding to the upland sur- face of the Kansan. The presumption is that the soil occurs in interglacial valleys which had been cut into the Kansan prior to tlie Illinoian invasion, and that the entire till deposit above the soil is Illinoian. The erosion thus indicated commonly shows a depth of less than 50 feet and harmonizes with the depth of i)re-IlHnoian valley erosion of the drift outside the limits of the Illinoian drift. There is, however, an occasional example of the occurren'ce EROSION OP THE KANSAS DEIFT SHEET. 121 of a buried soil in the district west of the hmits of the Illinoian, either under- neath or within the Kansan drift. This feature makes it necessary to leave open the question of the age of buried soils within the Illinoian area which occur at a level below the general elevation of the outlying Kansan di'ift. EROSIO?^^ OF THE KANSAS DRIFT SHEET. The pre-lUinoian erosion of the Kansan till sheet is a third evidence of the great length of the Yarmouth interglacial stage. Such erosion, as just noted, is suggested within the limits of the Illinoian by the occuirence of a buried soil below the general level of the Kansan di'ift surface. But evidence may be found in the portion of the Kansan drift lying outside the limits of the Illinoian which is not at all open to question. The evidence first to attract notice was that of the relative degrees of erosion displayed by the Illinoian and Kansan di'ift sheets. Prior to the discovery of the extension of the Illinois lobe into southeastern Iowa it had been noted by Chamberlin, as well as by the writer, that southern Iowa presents a more eroded appearance than western Illinois and the southeastern counties of Iowa, and the matter was discussed as a remarkable feature. In the district outside the limits of the Illinoian the original di'ift plain is preserved only in narrow strips along divides, estimated to comprise scarcely one-fourth of the surface, while in the district covered by the Illinoian drift the remnants are far more extensive, comprising apparently more than half the surface. The branching of drainage lines is also carried to markedly greater matui'ity in the Kansan than in the Illinoian drift. Definite means for determining the amount of pre-Illinoian erosion of the Kansan is afiForded by a study of the valleys in Kansan drift which connect with the abandoned valley of the Mississippi, which was occupied at the Illinoian invasion. These embrace the valleys of West Crooked Creek, Skunk River, and Big Cedar Creek. Valleys farther north have generally been greatly modified by the lowan invasion, and hence do not furnish good illustrations. It is found that the three valleys just noted have been cut at their points of connection with the abandoned valley to a depth of about 50 feet below neighboring uplands and to widths of about three- fourths of a mile, 1^ miles, and 1 mile, respectively, at the time the Missis- sippi was occupying this abandoned channel, i. e., at the Illinoian stage of glaciation. This width is two or three times that of the inner valleys, which 122 THE ILLINOIS GLACIAL LOBE. are now cut far below the level of the pre-Illinoiau valleys, but repre- sents nearly as much removal of material, and the removal was probably effected at a lower gradient, i. e., under less favorable conditions than are now afforded. In this comiection it should be noted that no CAndence has been found that the gradient of the streams was increased until after the lowan stage of glaciation. The inner valleys represent, therefore, post- lowan rather than post-Illinoian excavation. But this fact does not appar- ently set aside the estimate given above, for if the pre-Illinoian valley excavation had not reached the level of the channel opened by the Missis- sippi at the Illinoian stage of glaciation, that valley would have furnished a more du-ect and presumably more favorable line of discharge for all these streams than their present line. The featm-es along the present line of dis- charge for the thi-ee streams under consideration (eastward through Skunk River) strongly support the view that a pre-Illinoian valley was formed in the lower course of Skmak River. A broad terrace borders the portion of the valley below the point where Skunk River crosses the abandoned valley at Rome, which stands sufficiently low to have afforded a line of discharge for the portion of the valley west of the abandoned channel. This would have been blocked at the Illinoian ice invasion, but not necessarily con- cealed or greatly filled by Illinoian drift. Upon the withdi-awal of the ice, if it chanced to stand slightly lower than the Illinoian course of drainage, it would receive the post-Illinoian di-ainage and become the line of a reestab- lished stream. There is near the mouth of Skunk River an exceptionally clear illustra- tion of the work of that stream in the Yarmouth interglacial stage. By reference to fig. 4 it will be seen that a valley or depression turns away from Skunk River at Augusta and leads southward to Lost Creek. This valley is more than a mile in width and 30 feet or more in depth, and is excavated in the Kansan till. Evidently it was opened by Skunk River after the Kansan stage of glaciation and before the Illinoian stage. Whether it carried the whole or only a part of the stream is not yet known. The northern end has received only a thin coating of Illinoian drift. The southern end received a sufficiently heavy deposit of that drift to prevent its subsequent use as a drainage line. Since the Illinoian stage of glacia- tion the entire drainage of the river has been directly eastward into the Mississippi. Low swells of Illinoian drift occupy the south end of the ORGANIC EEMAINS, ]23 valley and show clearly that there has been no valley excavation there since they were formed. The valley of Lost Creek in Lee County, Iowa (see fig. 4), though lying wholly within the limits of the Ilhnoian drift, bears evidence of having been occupied and largely excavated by a pre-Illinoian stream. It presents a shallow trough cut in Kansan drift, which is covered, but not greatly concealed, by Illinoian drift. Low swells of till formed at the lUinoian invasion occm- on its slopes and bottom, thus proving its pre-Illinoian exca- vation. This valley is about one-half mile in width and 30 to 50 feet in depth, and holds this size nearly up to the head, which is found in the marginal ridge of Illinoian drift. It seems probable that prior to the Illi- noian invasion its drainage basin was much more extensive than at present. This affords an illustration of a partially reestablished stream. This vallej?- and that of the lower course of Skunk River are exceptional, for as a rule the pre-Illinoian tributaries of the Mississippi were so completely filled at the Illinoian invasion that the post-IUinoian drainage was opened along new lines. It is probable that the portion of the Mississippi between Mus- catine and Fort Madison, Iowa, is reestablished along a pre-Illinoian and also pre-Glacial line. ORGAlSriC REMAINS. As yet no specific identifications of the wood and smaller plants found at the Yarmouth horizon have been made, unless some of those reported by McG-ee from northeastern Iowa have this horizon. The wood appears on a superficial examination to be coniferous and largely red cedar. It is planned to have careful examinations made in the near future to ascertain the bearing the plants may have on the climate at the Yarmouth intergla- cial stage. It should be considered, however, that the plants found in the peat were presumably living just before the culmination of the Illinoian invasion, and may not aff'ord a true index of the interglacial stage ; for a general lowering of temperature probably preceded as well as accompanied the culmination of the ice sheet. Possibly a deposit will yet be found in which plant remains occur which were buried in the middle part of the interglacial period. The specimens of wood noted in the clay beneath the bed of peat at Yarmouth may have been buried at a sufliciently early date to be unafiPected by the Illinoian glaciation. Unfortunately no specimens of that wood are now available. 124 THE ILLINOIS GLACIAL LOBE. The animal remains (rabbit and skunk, see p. 42) found in tlie peat at Yai-mouth show a remarkable state of preservation, the marrow of the bones being still preserved, as noted in the examination by Dr. F. W. True. This is perhaps no more remarkable than the state of preservation of some speci- mens of the wood from the same horizon. Several of the wood specimens have been found to take fire as readily as the wood from our living forests. In not a few cases within the writer's notice leaves of grasses or sedges have been found in a fair state of preservation. Instances of the occur- rence of leaves of oak or other deciduous trees have been repoi-ted to tlie Avriter from the Yarmouth horizon, but none have come under his personal observation. The character of the hfe of this interglacial stage is a field promising much of interest, but which as yet is scarcely at all developed. (CHAPTER VI. THE SANGAMON SOIL AND WEATHERED ZONE. Between the disappearance of the IlHnoian ice sheet and the deposi- tion of the lowan till and loess there occurred an interval of deglaciation about as marked as that between the Kansan and Illinoian stages of gla- ciation, a period marked by leaching and oxidation of the Illinoian drift, of peat and soil accumulation, and of erosion. This interval was long since brought to notice by Prof A. H. Worthen in his report on Sangamon County, Illinois.^ For this reason, and because of the conspicuous development in the Sangamon drainage basin, it seems appropriate to name it the Sangamon interglacial stage. This name was suggested by the writer in a paper pre- sented before the Iowa Academy of Sciences in December, 1897. The following section, published by Worthen, was furnished him by a well digger, Joseph Mitchell, who had dug many wells in the northwest part of Sangamon County and in the adjoining jjortion of Menard County:^ Generalised section of xcells northwest of Springfield, Illinois. i'eet. Soil 1-2 Yellow clay 3 WWtisli (gray ?) jointed clay, with shells .'. 5- 8 Black muck with fragments of wood 3- 8 Bluish colored bowlder clay _ y-10 Gray hardpan (very hard) 2 Soft blue clay, without bowlders , 20-40 This section represents the formations beneath the upland plain near the western edge of the Sangamon watershed at an altitude 200 feet or more above the level of the mouth of the Sangamon. Worthen remarks ' Geol. of Illinois, Vol. V, 1873, jip. 306-319. -Op. cit., p. 307. 125 126 THE ILLINOIS GLACIAL LOBE. that the fossiliferous clay of the section- is undoubtedly loess. He calls attention also to the prevalence of conditions suitable for the growth of an arboreal vegetation jjrior to the deposition of the loess. In the section just given, the black soil appears to be the representative of the Sangamon interglacial stage. But this interglacial stage, like the Yarmouth stage, is often represented by a leached and slightl}- reddened till surface, unaccompanied by black muck. These two phases seem to lie mutually exclusive, there being but slight reddening of the till surface where the black muck is present, or but slight accumulations of black muck ^'N'hei'e the reddening of the till is pronounced. The black muck is developed in portions of the uplands where the surface is very level and conditions for drainage are defective, while the reddened soil is developed on the more undulatory tracts, where a fair condition of di-ainage probablv existed. The black muck phase is common in the Sangamon Basin, and also in the northern part of the white clay district of southern Illinois, and southwestern Indiana just outside the limits of the Shelby ville drift sheet. In western Illinois and southeastern Iowa it has a more restricted develop- ment, for the sui-face there is generally more elevated and better situated for the development of drainage lines than in the districts first mentioned. In southern Illinois and southwestern Indiana and throughout much of western and northwestern Illinois, the reddened till surface is a conspicuous feature. In certain areas an alternation of sand with peaty beds has been found between the lowan loess and the Illinoian till. This phase is apparently restricted to the borders of valleys where stream action has probably been influential but with intermittent activity, the sand being deposited b}' the streams, while the peat was accumulated at times when the streams failed to cover the land. The accompanying views, PI. X, A and B, taken in cuttings along the Santa Fe Railway in eastern Knox County, Illinois, show a dark soil (b) at the junction of the loess (a) and Illinoian till (c). In the exposures seen in these views, acid tests show the till to have been leached to a depth of about 4 feet below the dark-colored soil. The overlying loess is calcareous at base. The leaching, therefore, took place prior to the loess deposition in connection with the development of the soil. The depth of leacliing noted U. S. GEOLOGICAL SURVEY MONOGRAPH XXXVIII PL. X A. NEAR VIEW OF SANGAMON SOIL IN KNOX COUNTY, ILLINOIS. (a) Loess, partly eroded, 4 feet; {!>) Sangamon soil, 1 foot; (c) lllmoian drift, 4 feet. IJ. MORE DISTANT VIEW OF SANGAMON SOIL IN KNOX COUNTY, ILLINOIS, (a) Loess, 12 feet; (/j) Sar^garpon soil, 2 feet; (c) lliinoian drift, 40 feet. THE SANGAMON SOIL AND WEATHEEEU ZONE. 127 in this railway cutting represents about the average depth found in the interior portions of the district covered by the Ilhnoian drift. Along the borders of the drift, as previously noted, the Illinoian till is, in places, noncalcare- ous tlu'oughout its entire depth, and seems to be made up largely of the leached portion of the Kansan drift which it had overridden. Some care must be exercised, therefore, in deciding upon the amount of leaching which has taken place since the Illinoian ice sheet disappeared. In northern Cumberland County, Illinois, a short distance north of Greenup, Professor Chamberlin and the writer examined' exposures of the Sangamon soil in which -branching- root-like extensions of the soil penetrate several inches into the underlying subsoil. These are thought to mark the former presence of forests on that soil. In a few places peat beds of considerable depth have been found at this soil horizon. Some of the best instances occur a short distance west of the region in which the section reported by Worthen is found. The coal shaft at Ashland, Illinois, near the line of Sangamon and Cass counties, shows the following series of di'ift beds : Section of the drift beds in a coal shaft at Ashland, Illinois. Feet. Black soil 1^ Loess of yellow color 1 Loess of blue color 2 Peat and black sandy slush 22 Bluish gummy clay 20 Yellow till 30 Total drift 85 At the air shaft sand was found beneath the peat in the place of the blue gummy clay. At Virginia, Illinois, a well made by Mi*. Oldridge entered a bed of peat at the base of the loess at about 15 feet and continued in it to a depth of 28 feet, beneath which a blue clay was entered. An instance of the occurrence of animal remains in the basal portion of the loess, immediately above a deposit of peat, probably Sangamon, was long since brought to notice by Mr. Pratt, of Davenport.^ In a railway cutting made by the Chicago, Rock Island and Pacific Company, in the ' Proc. Davenport Acad. Sci., 1876, p. 96, PI. XXXII. See also Geol. of Iowa, by C. A. White, Vol. 1, 1870, p. 119. 128 THE ILLINOIS GLACIAL LOBE. west part of Davenport, Iowa, the following beds are exposed, as reported by Mr. Pratt, -who examined the exposure while the excavation was fresh : Section in railway cutting near Davenport, Iowa. Feet. 1. Ordinary prairie soil, altitude 167 feet above Mississippi River 1 2. Loess, iron stained and distinctly laminated with laminiB curved and in places interbedded with thin layers of sand; the deposit also contains small calcareous nodules and shells of the genera Succinea, Helicina, and Pupa 20 3. Bluish-gray clay, containing a few shells like those of No. 2; a tusk, several teeth, and other portions of Elephas primigenius (?) were found just at the junction between JS'os. 2 and 3... 3-5 4. Bed of brown peat in which the peat moss, Hypnum aduncum, was sufficiently well preserved to be identified; quantities of much decomposed coniferous wood were also distributed through this bed - 1 5. Dark-brown soil, resembling the peat, but more decomposed 2 6. Blue clay, very Tenacious, containing sand, gravel, and small bowlders, many of them distinctly glacier scratched, extending beneath base of cutting. The peat bed, Avith its associated soil and silts, is reported to have been exposed for a distance of 30 or 40 rods. Concerning it Dr. C. A. "White remarks:^ " This deposit is quite remarkable in many respects ; in none more so perhaps than in the fact that the bed of peat rests upon a bed of clayey silt and is in turn covered by a similar but much deeper one, these varying conditions evidently haAang been produced by the shiftings of the adjacent and then sluggish river in that very early period of its postglacial history." The Sangamon soil has been exposed by some of the streams within the limits of the Wisconsin di-ift, notably on the Embarras and Kaskaskia rivers and tributaries of the Illinois. It is found below loess or white clay, which in turn lies beneath the till of the Wisconsin di'ift. Two excellent exposures on Farm Creek, east of Peoria, Illinois, are shown in PL XI, figs. A and B. In the first (A) the soil is not shown, but there is a deeply leached and weathered zone at the top of the Illinoian. In the second (B) there is a bed of peat resting upon silt which bears some resemblance to the overlying lowan loess in texture, but is not so calcareous and is of a deeper brown color. Whether it is similar in origin to the loess can scarcely be decided. The writer also is inclined to question whether the silt below peat in the Davenport section just described should be referred to the lowan loess. Beneath the silt which underlies the peat shown in fig. B there is Illiuoian till, and this is leached to a depth of 3 to 4 feet. This section ^Op. cit.,p. 120. U. S. GEOLOGICAL SURVEY MONOGRAPH XXXVIII PL. XI uA^a,iii,a3s at.t^aS8^fe^Mh^'^. ,^, , -' %i^.^.. .1 EXPOSURE ON FARM CREEK, 7 MILES EAST OF PEORIA, ILLINOIS, (a) Bloommgton gravel terrace, 8 feet; (6) Shelbyville till sheet, 14 feet; (cl lowan loess, 10 feet; (d) lllinoian till, ^View taken by Dr. Samuel Calvin, May, 1898.) B EXPOSURE IN A RAILWAY CUTTING ON THE TOLEDO, PEORIA AND WESTERN RAILWAY, 7 MILES EAST OF PEORIA, ILLINOIS. (a) Bloomington gravel and cobble on slope, 6 feet; (6) Shelbyville till sheet, 8 feet; (c) lowan loess, 6 feet; (d) Sangamon peai bed, 3 to 5 feet; (ei Silt below peat, 2 to 5 feet. Below the silt there is lllinoian till leached and weathered at top, 4 feet, beneatn which It IS calcareous. (View taken by Dr. Samuel Calvin, May, 1898.) THE SANGAMON SOIL AND WEATHERED ZONE. 129 seems to indicate that for a time after the Illinoian sheet was exposed to atmospheric action the drainage conditions were good, but that subse- quently they became imperfect and the peat was formed. The possible relationship between the lower silt and the gumbo of the Mississippi Basin is discussed in connection with the latter deposit (p. 32). The wood found in association with the Sangamon soil and peat, like that of the Yarmouth, appears to be largel}^ coniferous. Wherever identi- fications have been attempted such woods have been found to occur, and specimens not critically examined have the aspect of the coniferous rather than the deciduous varieties of wood. The aspect of the flora is decidedly boreal. However, as noted in connection with the discussion of the vege- tation found in the Yarmouth soil, it is necessary to guard against the inference that the vegetal remains preserved in the peat and mucky portions of the soil furnish an index of the climatic conditions throughout the entire interglacial stage. They pertain only to the close of that stage when gla- cial conditions were being inaugurated, and may have an aspect very dif- ferent from that of plants which grew in the midst of an interglacial stage. Slight exposures of the Sangamon soil and weathered zone are to be seen on nearly every hillside within the limits of the Illinoian drift where erosion has opened a fresh exposure low enough to reach the base of the loess. A few exposures have been found within the limits of the lowan till, but such exposures are far less common than beneath the lowan loess. Several excellent exposures of the Sangamon soil have been made by railway companies at points where the overlying loess has been stripped off to obtain a filling for the railway track. For example, along the Van- dalia Railway, a few miles west of Marshall, in Clark County, Illinois, an area of more than an acre has been stripped of the loess, leaving the black mucky Sangamon soil at the base. A similar exposure, though less exten- sive, is found at West Point, Iowa. The presence of the black muck here seems somewhat remarkable, inasmuch as it occupies the crest of the marginal ridge of the Illinoian drift. The upper 6 or 8 inches is a deep- black color, beneath which there is a deposit of gray gumbo 2 or 3 feet in thickness, capping the Illinoian till. Extensive exposures of black muck below the loess have been made by the Chicago, Burlington and Northern Railway at the crossing of Johnson Creek, about 4 miles south of Mount MON XXXVIIl 9 130 THE ILLIISOIS GLACIAL LOBE. Carroll, Illinois. At this place the loess has a thickness of nearly 20 feet. The till beneath this buried soil has been leached as far down as exposures extend, 3 to 4 feet. Still another extensive exposure of the soil is found in the pit of the Brick and Tile Works at Galva, Illinois. The loess, to a depth of 15 feet, is used in the manufacture of the brick and tile, beneath which is a black mucky soil about 1 foot in depth, which caps the Illinoian till sheet. In this soil a log about 1 foot in diameter and several feet in length was found embedded. The conditions for erosion during the Sangamon interglacial stage seem to have been decidedly less favorable than in the Yarmouth stage. The streams apparently were so broad and sluggish as to cut only shallow val- leys, and these are seldom sharply outlined. The general absence of well-defined valleys beneath the lowan loess on the area occupied by the Illinoian drift sheet, when taken in connection with their conspicuousness in the Kansan drift, is liable to give the impression that only a brief inter- val separates the Illinoian from the lowan glacial stage. But if interpreta- tions are made from the leaching, and depth of peat and muck accumulation during the Sangamon interglacial stage, there are found indications of a period which compares favorably in length with the Yarmouth interglacial stage. The depth and degree of oxidation of the Illinoian, when compared with the lowan, are also impressive evidence in favor of a wide separation in the dates of deposition of the two deposits. The amount of erosion, therefore, appears to be a poor index of the length of the interglacial period, though if low altitude and slack drainage be assumed it easily harmonizes with the evidence of a long interval denoted by the other features of the drift. In discussing this matter with the several glacialists who are familiar with the deposits representative of each glacial stage the writer finds them unanimous in considering the Illinoian drift a much older deposit than the lowan. There is some difference of opinion as to whether the Sangamon or the Yarmouth is the longer interglacial interval. The wx'iter inclines to the opinion that the Yarmouth is the longer interval. X J a. > X X X I a < a. o o z o s LiJ > tn _] < o o o _J o q (/) 3 ■X. o O fl) ^ ■0 (U ni C y V •oo r: c o rt 00 ^ ^%! 2 ?^a .- - en £3 o w c p^ ^ — -ji H '-' ra t. 05 .:i SS id u 'J) X i- < X X X t J) >■ o o 5 O s -< 111 < c OJ > (J a o I- o ui o ro c l-H o i 03 CO CHAPTER VII. THE lOWAN DRIFT SHEET AND ASSOCIATED DEPOSITS. THE lOWAN SHEET OF THE ILLIKOIS LOBE. The sheet of drift to which the name lowan is here appHed is referred to the lowan stage of glaciation, not because of direct connection with the lowan drift of eastern Iowa, but because of an apparent similarity with the lowan drift of eastern Iowa in its connection with the great sheet of loess in the Mississippi Basin. As shown below, the loess overlaps this di-ift sheet only a short distance, and was deposited apparently while the ice sheet was melting away, there being no clear evidence of an exposiu'e of its till to pi'otracted atmospheric action prior to the deposition of the loess. DISTRIBUTION. The lowan sheet of the Illinois lobe was formed by a southwestward ice movement over northern Illinois. Its western border has been traced in some detail by Mr. Oscar Hershey, through Wiimebago, Ogle, Lee, and Whiteside counties. The writer had previously noted the occurrence of this drift in Winnebago, Ogle, and Lee counties, but had not attempted a precise mapping of its western border. The border is found to enter Illinois from Wisconsin at the valley of Sugar River, about 12 miles west of Beloit. It follows this valley south- ward to the Pecatonica Valley and thence, as shown in PL XII, passes up the Pecatonica about to the line of Winnebag'O and Stephenson counties, where it crosses to the south side of the river and returns eastward to the city of Rockford, thus forming a narrow lobe at the Pecatonica Basin, hav- ing a protrusion of about 12 miles and a width no greater than its length. This lobe is called the Pecatonica lobe, since it occupies a low district or basin drained by the Pecatonica River. ■^ 131 132 THE ILLINOIS GLACIAL LOBE. . ' Below Rockford the border is found to follow nearly the course of Rock River to the vicinity of Oregon. Here Hershey makes a division of the drift margin. The outer margin passes westward to Polo. The inner margin passes southward along or near Rock River to the vicinity of Dixon. It there crosses the river in a westward course and follows the north border of a lowland tract which extends a few miles back from Rock River. North of Sterling it joins the outer margin. Hershey's tracing of the outer margin was carried no farther than Polo, but the writer has examined the district south and west from Polo, and also the portion of this margin from Polo eastward to Rock River. Eastward from Polo there is a definite border, characterized by low swells of till, among which are saucer-like depressions, giving the surface a nmch fresher appearance than that of the older sheet which occupies the district to the north and west. At Polo the margin appears to swing south- ward and follow the east border of the Elkhorn Creek Basin into Whiteside County. The border is not so definite here, however, as east of Polo, there being only a few till swells and occasional basins in the outer part of the drift sheet. This line connects in eastern Whiteside County, about 5 miles northeast of Sterling, with the inner margin traced by Plershey. Hershey's chief criterion in mapping the inner border is a change in the character of the till, such as characterizes the margin farther north, that to the east of it being more sandy than that to the west and displaying a pink tint not noted to the west. The portion between the inner and outer margins has a more compact texture than the remainder of the lowan drift sheet. The cause for this difference is not yet apparent. The margin lies north of Rock River at least as far west as Rock Island Junction. There is a small area on the north side of Rock River, west from Rock Island Junction, in which a sheet of drift with fresher aspect than the Illinoian is found. It is apparently confined to a lowland tract whose north border is followed approximately by the Chicago and Northwestern Rail- road from Round Grove to Morrison, and whose west border lies along Rock Creek from Morrison south to the valley of Rock River. To the north and west of this lowland there is a heavy deposit of loess which largely con- ceals the underlying deposits, but the lowland has only a thin coating of loess except in a few ridges resembling the paha of eastern Iowa. Such an extension of the lobe as would be necessary to carry it to Morrison seems THE lOWAN DRIFT SHEET. 133 rather questionable, especially since it calls for a movement north of west. It is, however, not so narrow a tong-ue as appears to have been thrust west- ward into the Pecatonica Basin, and projects but 4 or 6 miles beyond a regu- lar border in line with that in eastern Whiteside County. The difficulties seem scarcely as great as would be involved in an invasion of ice from eastern Iowa into this district at the lowan stage of glaciation. There are, however, in northwestern Whiteside and southwestern Carroll counties features which raise the suspicion that ice from the Iowa side may have crossed into that district in the lowan stage of glaciation and extended as far east as the meridian of Morrison. It becomes necessary, therefore, to consider the question of an extension of the lowan ice sheet from Iowa southeastward into this tract. This question is considered later (p. 144). It is difficult to determine the position of the border of this ice sheet south from Rock River, since there is a broad area occupying the interval between Rock and Green rivers, in which heavy deposits of sand occur. Exposures of fresh-looking till north of Spring Hill seem to be of lowan age. South from the Glreen River sand deposits there is a narrow tract of low country extending eastward from Geneseo to the vicinity of Sheffield, in which there is very little sand, and also very little loess compared with the covering on the higher districts to the south, and which may prove to have been occupied by the Illinois lobe of the lowan ice sheet during the loess deposition. Its south border is within 2 or 3 miles south of the Chi- cago, Rock Island and Pacific Railway throughout the interval between Geneseo and Sheffield, and is marked by a bluft-like rise of 40 to 60 feet to a belt of heavy loess. Immediatel}^ east of Sheffield the outer moraine of the Wisconsin drift sets in, and no drift attributable to the lowan invasion has been recognized outside its limits in districts to the south. There appears, therefore, to be striking similarity between this lobe of lowan age and that which occupied eastern Iowa. They each show at the north remarkable pro- trusions, extending in both cases nearly to the borders of the Driftless Area. Their margins also are strikingly different in outline from those of preceding and succeeding sheets in the same districts. The east lowan sheet has been found to extend only about to the latitude of Rock Island and Muscatine, and possibly the lobe which we are considering extended no farther south. There are, however, till deposits in eastern Illinois, as far south as Iroquois County, which are suspected to be of lowan age, as indicated below. 134 THE ILLINOIS GLACIAL LOBE. TOPOGRAPHIC EXPRESSION. At several places along the border of this drift sheet in Winnebago, Ogle, and Whiteside counties low swells and ridges appear, but they are seldom more than 10 or 15 feet in height. These serve, however, to give definite- ness to the margin, although they are very inconspicuous features. In most cases the low swells' are plainly independent of drainage erosion, there being instances in which they pass across a valley which had been formed in the earlier drift, dotting its slopes and bottoms and passing onward over the bordering uplands in utter disregard of the drainage lines. Such knolls may be seen near the mouth of Leaf River in Ogle County, and also on the borders of the Pecatonica in Winnebago County. Along portions of the border the separation of the erosion features from the drift aggregations produced by this ice invasion is somewhat difficult. Such is the case on the borders of the lowland tract north and west from Sterling, where the imdu- lations are probably in part due to drainage erosion. A similar difficulty is experienced in the narrow belt of lowland east from Greneseo. There are present, however, in both these districts knolls and ridges of drift which appear to be independent of drainage erosion and referable to the inequali- ties of deposition of the ice. No paha have been found in Illinois except in western Whiteside and northwestern Henry counties in the districts in which some uncertainty is felt concerning the occupancy by ice at this stage of glaciation. The paha are scattered over the portion of Whiteside County north of Rock River from Round Grove westward to the borders of the Mississippi, but are best developed on the lowland tract south and east from Morrison and on the till tract between Rock and Green rivers, which leads from Spring Hill south- westward to the mouth of Green River. They are straight ridges, usually a mile or less in length, but occasionally reaching 2 miles. They are often sharp crested, with a width of scarcely 50 feet at top, and present abrupt slopes. Occasionally they reach a Avidth of 40 or 50 rods, including slopes. In height they range from 10 feet or less up to about 50 feet. The trend is quite uniformly about WNW.-ESE. Several of them may be seen in the Clinton topographic sheet, PI. XVIII (in pocket). The longest paha noted is found about 4 miles south of Morrison, and leads from the center of sec. 4 west-northwest to the noi-th line of sec. 6, T. 20, R. 5 E., a distance of about THE lOWAN DRIFT SHEET. 135 2 miles. It is interrupted by a narrow break in the west part of sec. 4, through which a small stream passes. This paha is 30 to 45 feet in height and 40 or 50 rods wide, including slopes. It presents the unusual feature of carrying basins on its slopes. One near the line of sees. 4 and 5 contains a pond with an area of about one-half acre. Another prominent ridge, appar- ently a paha, is found at Round Grove, that village being situated near its western end. The ridge is about 1^ miles long, 30 to 40 rods wide, and 20 to 40 feet high. It is separated by only a narrow sag, scarcely wider than the ridge, from an upland tract on the north which stands as high as its crest, and it may possibly be only a detached portion of that upland. It seems difficult, however, to account for a stream capable of causing its separation from 'ihe upland, and that interpretation would not be thought of if it stood like the paha last mentioned, some 3 miles from the upland. Just north of the village of Spring Hill there is a paha nearly a mile in length which rises about 20 feet above the general level of border districts and has a width of only 20 to 30 rods, including slopes. Several paha ridges appear on the low upland north of Green River in northwestern Henrv County. The most prominent ones noted are a group of three nearly parallel ridges crossed by the Geueseo and Sharon wagon road 3 or 4 miles north of Geneseo, in sec. 34, T. 18, R. 3 E. Their highest points rise 40 to 45 feet above the bordering uplands, and they are each nearly a mile in length. Shorter ridges of about the same height occur in sees. 31 and 32 of the same township and in sec. 4, T. 17, R. 2 E. There are in eastern Winnebago' and Boone counties till ridges elongated in an ENE.-WSW. direction, apparently the direction of ice movement, which are drumlinoid in form. These ridges have been exam- ined by Mr. I. M. Buell, in connection with his study of the drumlins of eastern Wisconsin, and he considers them a phase of drumhn development, though less perfect in form than the typical drumlin. These ridges usually have a length of a mile or less and a breadth scarcely half as great as their length. The higher ones rise 40 or 50 feet above border districts, but the majority are 30 feet or less in height. With these drumlinoid ridges there are associated knolls of nearly conical form, giving the surface a semi- morainic aspect. No definite morainic belts, however, have been traced across the district occupied by this ice sheet. The knolls appear in isolated clusters surrounded by plane-surtaced tracts of greater extent. 136 THE ILLINOIS GLACIAL LOBE. In the southeastern part of Winnebago County and in the portion of Ogle County between the outer moraine of the Wisconsin series and the present valley of Rock River, and also in southwestern Boone County, gravel knolls of considerable prominence are found. These in most cases appear to be a product of the lowan invasion, for the gravel has a freshness corresponding to that of the lowan till. In one instance (near King's Station, in Ogle County) a gravel knoll, opened for railway ballast, shows what appears to be a more aged gravelly deposit at the base than that constituting the body of the knoll. It had a height of 45 feet before the excavation was made, and several others in that vicinity are equally large, though the majority are 20 feet or less. A chain of sharp gravel knolls in southwestern Boone County, near Irene, trends north to south and has a length of over a mile. At the north it merges into a till ridge with gentle slope and with a smoother contour than the gravelly belt. This ridge, with the gravelly knolls, is probably a marginal deposit formed at a shght halt made by the ice. The knolls are only 20 to 30 feet high, but rise promptly from the boi'dering upland plain. Near Stillman Valley a few esker-like ridges of gravel are developed which trend northeast to southwest. These are closely associated with gravelly knolls, and the longest are only a mile or less in length. An esker-like ridge was also observed by Hershey near Sterling, Illinois. The greater part of the surface of this sheet of drift, like that of the lUinoian sheet, is plane or but very gently undulating and devoid of notable topographic featvires. The principal ridges and knolls associated with the drift sheet are represented on PI. XII, a reference to Avhich will serve to show the small percentage of the area occupied by them. THICKNESS OF THE DRIFT. In eastern Winnebago and northern Boone counties, Avhere the drum- linoid drift ridges and associated knolls abound, the drift of lowan age is known to have considerable thickness, possibl}' an average of 40 feet or more. Aside from this small district, the drift referable to the lowan invasion appears to form generally only a thin and somewhat patchy deposit. In the vicinity of the Ijorder the drift is often confined to the small knolls, ID or \h feet in hei"lit, tlic low oTound anion"- tlie knolls THE 10 WAN DEIFT SHEET. 137 being immediately miderlaiii by an older sheet of drift. On hillside expo- sm-es also, some distance within the border, it has been fonnd that in places a thin deposit of lowan drift occurs at the tops of hills, ^yhile the greater part of the slope exposes Illinoian drift. In not a few places in the midst of the lowan drift area only the Illinoian drift is fonnd at the tops of the hills, though the hills were apparently covered by the lowan ice sheet. There is apparently a smaller amount of loess associated with this ice lobe than Avith the lowan of eastern Iowa. The districts immediately outside its border have only a thin coating, 5 or 10 feet, while the thickness of the loess within its bordei's is even smaller in amount. It Avould seem a liberal estimate to allow an average of 10 feet of both till and loess as the product of the lowan invasion in Illinois. It is therefore sufficient to modify but little the features of the country which it occupies. STRUCTURE OF THE DRIFT. The drift of the lowan invasion has generally a more sand}^ constitu- tion than that of the Illinoian which underlies it. Along- the was'on roads and in other situations where it has been exposed to the action of slight wash, it frequently presents the appearance of fine sand, where the Illinoian drift would present the appearance of clay. Not infrequently the matrix appears to be nearly free from clayey material. There are other places, however, where the till has a stiff clayey matrix, but is readily distinguish- able from the Illinoian by its fresher surface Associated as this till sheet is with the loess, the latter being apparently a derivation from the former, a sandy till is a natural product, the fine material being carried into the loess. This difference in the two tills greatly affects the character of the soils. Where the lowan drift is present a dark soil is usually developed, while in the outlying districts of northwestern Illinois the soil is of a yellow or brown color. In places the lowan till is covered to a depth of several feet by loess, but in the Pecatonica Basin and much of the country east of Rock River the loess amounts to scarcely more than a skim coating 1 or 2 feet in depth, a coating such as may have been deposited by wind action since the final withdrawal of the ice sheet or have accompanied the melting of the ice. The portions best protected by loess present a till scarcely at all stained or 138 THE ILLINOIS GLACIAL LOBE. leached by atmospheric action, a feature which seems to indicate that the deposition of the loess closely followed the withdrawal of the ice. Within the limits of the Pecatonica lobe there is a very sandy till liberally set with small fragments of limestone and usually leached to a depth of 2 to 4 feet. East from Rock River, in Winnebago and Boone counties, the till is, on the whole, less sandy than west of that stream. Several exposures were noted in railway cuttings between Roscoe and Caledonia in which the till becomes calcareous at a depth of but 1^ to 2 feet, but there is usually leaching to a depth of 3 feet or more. Exposures of lowan till were noted by the writer on the south and east borders of the city of Dixon. One on Second street and Dumont ave- nue shows a thin sandy capping, beneath which is fresh-looking calcareous till. Farther east the sand disappears, yet the till is found to have suffered leaching only to a depth of 3 or 4 feet and is markedly fresher than the Illinoian. In the south part of Dixon, along the Chicago and Northwestern Railway, the first cutting east of the crossing of the Illinois Central Rail- road shows a calcareous sand, apparently lowan, resting on a leached till in which no effervescence with acid could be obtained within 5 or 6 feet of top. In exposures farther east a thin capping of loess rests directly on the Illinoian till. There appears, therefore, to be only a patchy deposit of lowan drift in the vicinity of this city. Hershey has noted several expo- sures of the lowan between Dixon and Sterling, and west from there to Rock Island Junction. The common phase is a very sandy till, in places becoming clear sand. In railway cuttings east from Polo low knolls belonging to the lowan drift have been well exposed. They are capped by about 4 feet of loess- like silt, beneath which the till is found to be calcareous from top to bottom. It is more clayey than in exposures near Dixon and Sterling. In this locality the lowan drift appears to be restricted mainly to the knolls, for exposures of the llliiioian drift appear in ditches made by the railway in crossing the low tracts among the knolls. At the village of Stratford, 5 miles east of Polo, the railway exposes a bed of fossiliferous silt at the base of the lowan drift, resting on an old land surface formed on the Illinoian. The fossils appear to be entirely of one species (Succinea avara). In two other localities fossiliferous silts have been found at the base of the lowan, one being in the railway cuttings on the Illinois Central immediately west of Irene, in southwestern Boone County, ;nid another in the railway THE lOWAK DRIFT SEIEET. 13^ cuttings on the Chicago and Northwestern, 1 mile east of Belvidere. Here, as at Stratford, the fossils are mainly of one species (^Succinea avara). The pebbles and smaller rock constituents of the till appear to be largely limestone whose native ledges are distant but a few miles to the east and north. In this respect it conforms to the structure of the underlying lUinoian sheet, and it seems not improbable that it has obtained much of the material from the lUinoian. There is not found between the lowan and Illinoian till sheets of the Illinois lobe such a striking contrast in rock constituents as is reported by McGee and by Calvin to be found in the lowan and Kansan of northeastern Iowa. The lowan is reported by Calvin to carry scarcely any pebbles or lai-ge rock fragments of local deiivation, while the underlying Kansan is thickly set with them. The paha ridges of western Whiteside and northeastern Henry coun- ties' usually contain a peculiar phase of loess. The basal portion is a fine sand, rather than loess, in which many of the individual grains may be seen by the naked eye, though with some difficulty. The great majority of grains of ordinary loess are much too fine to be seen with the naked eye. From Round Grove the fine sand at the base of the paha ridge has been shipped to Chicago foundries for use as a molding sand. In some cases the upper portion of the paha assumes a sandy consti- tution. As a rule, however, it consists of a loess similar to the bluff loess of the main waterways, and its banks will stand in vertical walls for j^ears. Like the bluff loess, it is fossiliferous, but as yet, so far as the writer is aware, no determination of the species of fossils represented has been made. Before leaving this subject a few sections are presented from the debatable district in central and southern Whiteside County, which serve to show the freshness of the till and the occurrence of more than one drift sheet. A well made for Mrs. Seeley on the slope of the Round Grove Ridge, at a level about 10 feet from the basg, is reported by the driller to have penetrated the following beds : Section of -well of Mrs. Seeley at Bound Grove, Illinois. Feet. Earthy soil and subsoil 3 Fiue yellow sand 5 Yellow clay, no pebbiec: noted 5 Sol't blue pebbly clay (pro'oably lowan till) S Black dirt with wood embedded (probably Sangamon) 2 Till mainly of blue- gray color (probably Illinoian) 17 Limestone. 140 THE ILLINOIS GLACIAL LOBE. Tlie reference of tlie soft blue clay of tliis section to the lowan is apparently supported by an exposure a short distance west of Round Grove, where the excavations at the side of the railway show a soft till wliich, though yellow at top, assumes a blue color within 3 or 4 feet of the surface. It has an appearance as fresh as any exposure of lowan till noted in districts to the east. The exposure is not sufficiently deep, however, to show the depth of this till or to enable one to determine whether an older sheet underlies it. Directly east of Round Grove about 1^ miles, the loess is found to rest upon a till having- leached and reddened sui-face, evidently as old as the Illinoian. These features indicate either that the lowan ice failed to cover the district immediately east of Round Grove or that it did not form a continuous sheet of till. The first interpretation seemed to the writer at one time the more probable, but further reflection and considera- tion of the fact that this drift sheet is somewhat patchy in the districts to the northeast has led to a more favorable view of the second interpretation. If the fresh-looking drift found west of Round Grove is of lowan age, the district to the east of that village was probably covered by that ice lobe. West and south of Morrison, on the borders of Rock Creek and east- ward from its valley, sandy till of fresher appearance than the Illinoian was noted at several points. In some cases it is found to be calcareous within 3 feet of the surface. At the point where the wagon road ascends from Rock River Valley toward Spring Hill an exposui"e was found in which the loess rests directly upon an unleached surface. It seems scarcely probable that there had been erosion of the till prior to the loess deposition, for the till .surface there rises to its usual elevation in that locality. In the cases above noted also no evidence was found of any removal of the surface por- tion of the till. Exposures of till are rare in this region, partly because of the shallow depth of valleys and partly because of concealment by loess. The few above noted comprise alL that were observed by the writer in central and southern Whiteside County. STRI/E. A few exposures of stritie have been found in Winnebago and Ogle counties which fall within the limits of the lowan drift sheet, but which are not referred positively to that ice invasion, since they may be referable to lOWAN DllIFT SFIEET AND ASSOCIATED DEPOSITS. 141 the Illinoian. These have all been observed by Buell, who has kindly furnished a list of the localities and bearings for publication. They appear in the list on page 88. PROBABLE EXTEZSTT OP lOWAN DRIFT SHEET BENEATH THE WISCOKSIN. The extent of the lowan drift beneath the Wisconsin can be deter- mined only approximately, and chiefly by inferential reasoning. An infer- ential determination may be based upon the occurrence of a series of drift sheets sufficiently full to include the lowan. For example, if there is but one older sheet of drift near the southern or western border of the Wiscon- sin, and if upon passing back beneath the Wisconsin two distinct sheets of older drift are found, it may be inferred that the additional sheet is either the lowan or is a sheet still older than the Illinoian. A series of well sections have made it evident that there are three well-defined drift sheets in the northern portion of eastern Illinois, two of which are older than the Wis- consin. It may be difficult to determine whether the additional sheet is of lowan or pre-Illinoian ag-e, since the data are based almost entirely upon well sections, and the material thus obtained is scarcely adequate for a satisfactory determination. The complicated series extends as far south as southern Iroquois County, and may possibly extend into Vermilion and Champaign counties, though the sections obtained in those counties do not furnish such decisive evidence of the triple series as is found in Iroquois County. The Wisconsin drift may usually be readily separated from the older sheets which underlie it. Its uniform blue color and the ease with which it may be penetrated by auger or spade enables the well drillers to distinguish it readily from the underlying deposits, which are of brown or g'ray color and more difficult to penetrate. There is also in many places a black soil at the junction of this sheet with the underlying drift which furnishes addi- tional evidence of the passage from the Wisconsin to an older drift. The well records obtained in the flowing well district of southern Iroquois County have brought to light the occurrence of a second soil at a horizon 25 to 50 feet or more lower than the base of the Wisconsin drift. There is often considerable peat at this lower soil horizon, and with it a large amount of water-bearing sand from which the flowing wells are obtained. 142 THE ILLINOIS GLACIAL LOBE. The peat in one instance is found to. have a thickness of 30 feet (in a well on Dr. Ludden's farm, 5 miles south of Clayton), and not infrequently has a thickness of 5 or 10 feet. Few wells have been sunk below this lower soil horizon, but these indicate that the di'ift may extend in places to a con- siderable depth. In several cases, however, the bottom of the di-ift was reached within 20 or 30 feet below the lower soil. Both sheets of drift beneath the Wisconsin are described to be of a brown or brownish-g-rav color, and the writer was unable to learn of any distinguishing character- istics. They are each described to be harder to penetrate than the overly- ing Wisconsin drift. In its sm-face exposures the lowan is usuallv more easily penetrated by a spade or auger than the Illinoian, and this fact may seem to favor the view that the two sheets beneath the Wisconsin in Iro- quois County are Illinoian and pre-Illinoian rather than lowan and Illinoian. However, the information is so meager and the character of the observa- tions so imperfect that it can scarcely be decided from these records whether the middle sheet is lowan or Illinoian. The following data con- cerning the three sheets in Iroquois County will serve to set forth their relative thickness: Clayton and vicinity. Feet. Upper or Wiscousiu drift sheet 60 or 70 Middle drift slieet 30 or 35 Lower drift sheet 45-|- Ash Grove timber belt. Upper or Wisconsin drift 55 or 60 Middle drift sheet 30 or 40 Lower drift sheet 50-f- Grescent City and vicinity. Feet. Upper or Wisconsin drift sheet 60 Middle drift sheet 1.5 or 20 Lower drift sheet 70-f- ' Onarga and vicinity. Feet. Upper or Wisconsin drift sheet 50 or 60 Middle drift sheet 30 or more L'ower drift sheet 175i Oilman and vicinity. Foet. Upper or Wisconsin drift sheet 75 Middle and lower drift sheets 120 J; low AN DEIFT SHEET AND ASSOCIATED DEPOSITS. 143 Milford and vicinity. Feet. Upper or Wisconsin drift sheet . ..• 50 j^ Middle drift sheet 40 or 50 Lower drift sheet 25 Donovan and vicinity. Feet. Upper or Wisconsin drift sheeit - 100 J^ Middle drift sheet 40 Lower drift sheet 30 In counties farther north a series is found similar to that displayed in Iroquois County. It is best shown in localities where the drift is very thick, as is the case in much of Kane, Uekalb, and McHenry counties. As these counties are adjacent to the exposed portion of the lowan drift sheet and equally far to the north, there is scarcely a doubt that the middle sheet should be referred to the lowan. Numerous sections of wells in these counties are presented in the portion of this report dealing with the wells of Illinois (Chapter XIV), together with a discussion of the probable age of the sheets, where more than one was penetrated. From these it may be seen that the Middle or lowan drift, as in the exposed portion, is much thinner than the Wisconsin and has a depth about the same as the middle sheet in Iroquois County. These points of resemblance, although not demonstrative of contemporaneity, at least suggest the possibility that the lowan drift extends into Iroquois County. A loess-like silt, as shown below, covers the Illinoian di-ift of southern Illinois outside the limits of the Wisconsin and is traceable northward several miles beneath the Wisconsin. This appears to be a deposit of lowan age like the loess of western Illinois, and, like the loess, it may be derived from the ice sheet. Its presence in southeastern Illinois and also in districts farther east, for it is found as far east as central Ohio, is thought to bring strong support to the view that the ice sheet, at the lowan stage, did not fall short many miles of reaching the line occupied at a later date by the Wisconsin ice invasion. This silty outwash is of sufficient volume to mantle the region, as far south as the Ohio River, with a deposit having an average depth of probably 5 feet. The volume of this deposit would seem to indicate that the southern limits of the ice sheet from which it was derived were at least within 100 miles, and possibly much nearer, the south- ern limits of the Wisconsin drift sheet, not only in Illinois, but in Indiana and Ohio. 144 THE ILLINOIS GLACIAL LOBE. PROBABLE EXTENT OF THE IOWA PORTION OP lOWAN DRIPT. InasniLicli as there is some evidence suggesting a slight extension of ice from Iowa into northwestern Illinois at the lowan stage, the question of the extent of that ice sheet is liere considered. The "upper till" of northeastern Iowa now classed largely as lowau di-ift is represented by McGree to have its eastern border near the western edge of the Driftless Area from the Minnesota-Iowa State line southeastward to the southern point of the Driftless Area near Sabula, lowa.^ Generally it falls short a few miles of reaching the Driftless Area, but in southern Jackson and in Clinton County, Iowa, it is represented to extend beyond the earlier sheet and to constitute the border of the Driftless Area. It is represented to extend to the Mississippi Valley from northern Clinton County southward to Scott County, and to fall short but a few miles of reaching that valley in Scott and Muscatine coimties. A tectonic map^ represents the ice sheet to have extended across the Mississippi and rested on the east bluff for a few miles below Clinton. From Muscatine County westward the limits are not definitely given. The upper till, however, is represented to extend to the limits of the district reported upon. The investigations carried on by the Iowa survey have supported the mapping and results of McGee in a general way, but not in all details. Very little disagreement as to the boundary is found from the Minnesota- Iowa State line southward to Delaware County, Iowa. But from that county southward to eastern Jones County Professor Calvin, of the Iowa survey, places the limit of lowan diift a few miles inside McGee's limit. There are certain extramarginal phenomena recognized in the disputed ter- ritory which he considers closely related to the lowan invasion, but not requiring the presence of lowan ice, chief among which are heavy accumu- lations of loess and a tendency to ridging of the loess in lines trending from WNW. to ESE., as in the undoubted lowan area. From northern Jones Count}' eastward to the Mississippi the border has not yet been investigated by the Iowa survey, but the writer made some examinations in this district in 1894 while engaged in tracing the west border of the Illinoian drift. ' The examinations were begun in Clinton County and carried westward. On the uplands northwest of Clinton a belt I Eleventh .\nii. Kept., U. S. Geol. Survey, PI. XLIV. •'Op. cit., PI. LVI. EXTENT OF IOWA PORTION OF lOWAN DRIFT. 145 of thick drift was discovered along which rock is seldom encountered at less than 80 feet, and in places the drift reaches a thickness of 200 feet or more. This thick belt of drift has a breadth of 3 or 4 miles and at first was conjectured to be the marginal ridge of the Illiiioian drift, though it is somewhat broader than the general width of that ridge in southeastern Iowa. It carries a thick capping of loess (20 to 30 feet or more) which greatly obscures the glacial deposits. A few exposures were found, however, which showed a surface reddening and leaching of the till such as is displayed in the Illinoian or Kansan sheets of drift. Such reddening has not been found in loess-covered portions of the lowan drift in northwestern Illinois, nor, so far as the writer is aware, has it been noted in the lowan drift of north- eastern Iowa. These observations were made in the district where only the upper till is represented on McGee's map. The Avriter, therefore, inferred that the upper till here should be considered Illinoian and proceeded west- ward, expecting to find the belt of thick drift swing southward to connect with the margin of the Illinoian already traced to western Scott County. It was found that the "Goose Lake Channel," described by McGee as an old course of the Mississippi, cuts through this belt immediately south of the village of Goose Lake (see PI. XVIII). From the west side of this broad valley the belt continues nearly due west across northern Washington and Welton townships, occupying its usual width of 3 or 4 miles and constituting the divide between the Maquoketa and Wapsipinicon rivers. It there takes a course noi'th of west, passing between Elwood and Lost Nation and still constituting the water parting between the two drainage systems. Slight incursions into the district north of this belt shoAved only thin deposits of drift resting on or mingled with residuary clays. The thick drift was traced to the vicinity of Onslow in Jones County, and there the examination was dis- continued, for it had become evident that this belt of drift could not connect with the Illinoian margin in Scott County. In returning eastward it was found that the thick drift, with its heavy coating of loess, lies along the north edge of a plain of lowan till, strewn with the immense bowlders characteristic of that deposit and presenting only thin or patchy develop- ments of the loess. At Dewitt Prof J. A. Udden joined the writer for a couple of days' study, and a trip was made together from Dewitt to Sabula. The large MON xxxviii 10 146 THE ILLINOIS GLACIAL LOBE. lowan bowlders were found east as well as west of Goose Lake Channel, as far north as the south edge of the belt of thick drift, but were not observed .farther north. The first night was spent at Bryant, near the north edge of the belt of thick drift, and in the vicinity of this village a few exjDOSures of the drift were found at the base of the loess, all of which showed a leached and reddened surface. Continuing northward from Bryant to Miles the loess was found to remain nearly as heavy as on the belt of thick drift, but the g-lacial deposits were very much thinner and seemed to be restricted to small bowlders and pebbles of crystalline pre- Cambrian rocks. These were usually found embedded in a slightl}- dis- turbed residuary clay of a deep reddish-brown color which can scarcely be called till, the commingling of pebbles with i-esiduary material being so im^jerfect. Between Miles and Sterling the sui-face is ridged in a peculiar manner, though somewhat similar to the paha of the neighboring- county on the west (Jones County) in trend and form, the trend being WNW. to ESE. and the form somewhat similar to an inverted canoe. The wells made on these ridges were reported to have penetrated "clay and quicksand," and in some cases have reached a depth of 40 feet without entering solid rock. As no exposures were found, the precise natm-e of the deposits remain unde- termined. A few granitic and greenstone pebbles were found in raA^iues between Sterling and Sabula, showing that the glacial deposits occur a few miles outside the limit mapped by McGee. Reviewing the above observations, it appears that nothing to suggest the occurrence of lowan drift was found along or north of the belt of thickened drift except the paha-like ridges near Miles, and there the resemblance is not known to carry with it the interpretation that they are of similar origin or date to the paha of the clearly recognized lowan drift. At best the i)aha are still an enigma from which as yet nothing can be proved. In view of the very thin and somewhat jiatchy development of the Iovv;ui drift near tlie terminus of the lobe in Ogle and Lee counties, Illinois, some hesitancy is felt in declaring the lowan drift to be absent from northern Clinton and southei'n Jackson counties, Iowa. For in tlie latter counties tlie heavy deposits of loess greath* interfere witli the determination of its extent. The occurrence of a sheet of drift markedly older than the lowan in the district mapj)ed by McGee as occu])ied only by upper till is abundantly evident. The thickened bc^lt of this ohler drift merits further EXTENT OF IOWA PORTION OP lOWAK DRIFT. 147 investigation, especially since in some of its features it sugg-ests a terminal moraine. During the past season (1897) the writer, together with Mr. Oscar Hershey, made further observations in eastern Clinton County, Iowa, as well as in Hem-y, Whiteside, and Carroll counties, Illinois. At Clinton the glacial deposits on the bluff of the Mississippi are found to be very thin, amounting usually to but 5 or 10 feet. These deposits, however, appear to be capable of separation into two distinct till sheets. One is reddened and leached at the junction with the overl3dug loess and apparently is nmch older, while the other is scarcely at all leached or stained at the junction with the loess and in one locality appears to graduate upward into loess. The former deposit is probably of Kansan age while the latter ajDpears to be lowau. The best exposure noted is found a short distance northwest of the Clinton Brewery in sec. 1, Clinton Township. The loess here has a thickness of 20 to 25 feet. At its base, near tlie east end of the exposure, is a fresh-looking calcareous till, about 4 feet thick, resting upon a bed of rotten, deeply stained gravel which there caps the older till. A few rods west the older till comes up to the base of the loess and farther west there are several exposures in which the loess rests directly upon the older till. Had the exposure of fresh till not been observed, there would have been nothing to indicate the presence of an lowan drift at this locality. Such being the case here, where exposures are extensive, it can scarcely be afhrmed that the lowan drift is not present in the district immediately north and west, where only slight exposures can be found beneath the heavj^ covering of loess. The exposure just mentioned was visited in November, 1897, by Messrs. Calvin, Udden, Bain, and the writer, and the interpreta- tion given above was assented to without reserve. Hershey and the/writer noted two exposures in the bluff in the north part of North Clinton (formerly Lyons) in which a few feet of fresh-looking till rests directly upon the residuary clay of the underlying limestone, a till which seems referable to the lowan rather than Kansan. Southwest of Clinton along the Burlington, Cedar Rapids and Northern Railroad bowlders were noted by Messrs. Cal- vin, Udden, Bain, and the writer near the east bank of the Mississippi. They are of the large angular type recognized by Calvin as charactei'istic of the lowan, and they occur on a gently undulatory plain, such as is also characteristic of the lowan. Similar bowlders were observed by the same 148 THE ILLINOIS GLACIAL LOBE. part)' of geologists near Long Grove in northern Scott County, and are reported to occur for several miles farther east. Here also they occur on a plain referred with some confidence to the lowan stage of glaciation. Hav- ing traced undoubted Towan deposits to the border of the Mississippi, it becomes a matter of interest to determine whether the lowan ice crossed into Illinois. The examination made by Mr. Hershey and the writer in Whiteside and CaiToll counties, directly east from the district just discussed, brought to light several features of a puzzling nature, some of which may have direct bearing upon this question. These features fall into live classes, (I) fresh till; (2) a tract free from loess; (3) a sand border east of the fresh till; (4) a loess apron outside the sand border; (5) ridges of loess with similar trend to the paha of the lowan drift area. Certain other features found in southern \yhiteside and northwestern Henr}' counties are considered in con- nection with the probable extension of the Illinois lobe at the lowan stage. The features here considered lie outside the prol^able limits of that lobe. Deposits of fresh-looking till occur on the elevated upland about 10 miles due east of the north part of Clinton, near the south line of sec. 13, Ustick Township, and near the west end of the line of sees. 18 and 19, Clyde Township, Whiteside County. The till has a yellowish-gray color similar to that of the lowan near Polo, in Ogle County, and effervesces at a depth of less than 2 feet from the surface of the ground. As the exposures occur in the midst of a tract nearly free from loess, there is nothing to protect the till from leacliing. It is in marked contrast to numerous other till exposures in the immediate neighborhood, which show decidedlv stronger surface stain and are leached to a depth of 5 or 6 feet. These exposures of fresh-looking till were visited by Calvin, Udden, Bain, and the writer in November, 1897, and by all were recognized to present a much fresher appearance than the surrounding exposures. It was also recognized that advantages for erosion here seem no greater tliau at })oints where a stained and deeply leached surface is presented. Althougli several ditferent lines have been traversed by Hershey and the writer in Carroll and western Whiteside counties, no otiier exposures of such fresh till have been noted outside of tlie possible limits of tlie lowan sheet formed by the Illinois lobe. These exposures, it will be observed, occur witliin tlie limits of a single square mile. Taken by themselves they seem a wenk, tliougli perliaps not EXTENT OF IOWA PORTION OF lOWAN DRIFT. 149 uncertain, prop to support the hypothesis of an extension of ice from Iowa into Illinois at the lowan stage of glaciation. The elevated tract just noted stands near the south end of a strip which is nearly free from loess. The strip extends northward several miles into Carroll County and has a general width of only about 2 miles. It is in decided contrast with the thick belt of loess on the west which follows the east bluff of the Mississippi and probably averages not less than 30 feet in average depth. It is also in contrast with the district on the east which for a distance of several miles back is covered to a depth of 12 to 15 feet with loess. On the south also there is heavy loess separating this tract from a similar tract south and east of Morrison. The tract with scanty loess is in an exposed situation, but apparently no more so than the bluff of the Mis- sissippi both to the west and south. It, therefore, seems difficult to account for its scant deposition by the force of the wind. It stands like the fresh till as a feature out of harmony with the general features of the region. It seems, however, to have a parallel in the region of lowan drift to the west, where similar areas free from loess are bordered by loess-covered tracts. In this connection it ma}" be remarked that the belt of loess along the Mississippi bluff leads down the river from far to the north and may be somewhat later than the loess to the east, and possibly subsequent to the occupancy of eastern Iowa by the lowan ice sheet. East of this tract characterized by thin loess is a narrow sandy belt in which dunes are common. This belt is best developed in Clyde Township, Whiteside County, where it has a breadth of fully 1 mile. Its southern end is found at Rock Creek Valley about 5 miles above Morrison, as indi- cated on PI. XII. From this point it bears slightly west of north into Carroll County, lying mainly east of the valley of Little Creek. Its general altitude is slightly lower than the tract on the west, but it has about the average elevation of the region, being not less than 200 to 250 feet above the Mississippi River. It is so far removed from the river as to be outside the range of the eeolian deposits which in places accumulate on the east bluff. The best developed portion, as may be seen by reference to PL XII, stands 6 to 10 miles back from the river bluff and is separated from it by the still more elevated tract just discussed. On the south, east, and north borders of the sandy belt there is a blanket of loess 12 to 15 feet thick near the margin of the sand, but decreasing 150 THE ILLINOIS GLACIAL LOBE. in thickness to scarcely lialf that depth within a few miles east or north, beyond which for many miles it continues thin. The distribution and general relations of this loess in reference to the district west of it present some points of similarity to the loess borders of the loAvan drift in north- eastern Iowa where the loess is considered an outwash or overwash apron from the ice sheet, formed while it occupied the neighboring tracts of lowan drift, which are nearly free from loess. The thinning out of the loess upon passing a few miles back from the hypothetical ice margin, as well as the abrupt border next the ice margin, may liere find illustration just as in Johnson County, lowa.^ The remaining feature bearing upon the question of the Iowa invasion into northwestern Illinois is that of canoe-shaped ridges of loess, with parallel shallow troughs, having a WNW.-ESE. trend. Such ridges and troughs are best developed in a belt of thick loess lying between the strip of thin drift just considered and the valley of Eock Creek in western Whiteside County (see PI. XVIII), There are other well-defined ridges, as already noted, south and east of Morrison, in the lowland tract nearly destitute of loess, and a few have been found south of Rock River in northwestern Henrv County. There is a faint development of this class of ridging in northern Rock Island County, Illinois, and in southern Scott and eastern Muscatine counties, Iowa. It is, perhaps, significant that they are best developed in the district lying between the well-defined phases of the lowan drift of the two ice lobes. While the origin of this class of ridofes like that of the loess sheet is in all probability attributable to a combination of aqueous and seolian agencies the precise mode- of action and relation of the two agencies have as yet received no adequate explanation. These ridges and bordering troughs were apparently developed before the present drainage lines had been opened in that region, if not while the ice occupied the neighboring drift plains on which the loess is a scanty deposit. The length of the ridges ranges from a fraction of a mile to two or three miles, but the width seldom reaches one-eighth of a mile. In height they range from 5 feet or less up to about 50 feet. While usually made up of typical loess they occasionally include fine sand, as noted above (p. 139.) Aside from the; canoe-shaped ridges of loess there are found other forms of loess and sand aggregation in the region under discussion. On the east 1 See Calvin, Iowa Geol. Survey, Vol. VII, 1897, pp. 86-90; also iiiup of .lohnson County, p. 92. EELATIOK OF ILLIISrOIS AND IOWA ICE LOBES. 151 bluff of the Mississippi Valley, opposite the broad sandy bottoms, stich as occur in southwestern Carroll and northwestern Whiteside counties, sandy knolls and ridges are found which are evidently due to wind action. Some of them are in process of drifting- even to-day, for the sand is too barren to nourish an adequate protective cover of vegetation. These ridges are irregular in form and trend and seldom bear a resemblance to the canoe- shaped ridg-es of loess. A few sandy ridges are found on the strip of drift in southwestern Carroll County, above noted, where the loess is scanty, which like the canoe-shajjed ridges of loess have a general WNW.-ESE. trend. They are, however, more in-egular in form and are usually broader than the loess ridges. Possibly they should be classed with the dunes. If all the features of the region just discussed be considered, it appears that positive e^adence of the invasion of the Iowa ice into northwestern Illinois at the lowan stage of glaciation is at best very weak. The features, however, appear to favor rather than to antagonize the hypothesis of such an invasion. The debatable ground is restricted to a belt but 10 or 15 miles wide on the north and east borders of unquestioned lowan drift. It embraces northern Clinton and southern Jackson counties, Iowa, and south- western Carroll, western Whiteside, and possibly neighboring portions of Rock Island County, Illinois. Were this belt low, like the tracts occupied by the lowan drift in Clinton and Scott counties, Iowa, the extension might be granted, even with a very limited occurrence of fresh-looking drift. But the fact that the debatable region, both on the north and east, stands 100 to 300 feet above the low plain of lowan drift, necessitates a very careful study of the evidence in the light of all applicable hypotheses. Having set forth the available data, the question is left open with the hope that either by the light of further data or by more mature reflection a satisfactory solution may be reached. RELATION OF THE ILEIJfOIS AJSTD IOWA ICE I.OBES. In concluding this discussion a few remarks seem necessary concerning the probable relation of the Illinois and Iowa ice lobes at the lowan stage of glaciation. In his paper on northeastern Iowa, above quoted, McGee considers it probable that at the invasion now called lowan the ice from the Iowa side culminated earlier than that on the Illinois side, and caused a displacement of the drainage of the Mississippi near Clinton, southeastward 152 THE ILLINOIS GLACIAL LOBE. to Rock River.^ He has rejDresented the Illinois lobe to have subsequently extended to the border of the Mississippi Valley in Wliiteside and Rock Island counties, and to have led to the flooding of the Driftless Ai-ea, forming what is termed Lake Hennepin.^ It would appear from McGee's discussion that the dates of culmination of the two lobes were separated l^y only a brief interval, an interval which in no wise compares in length with that which has been found to have occurred between the Kansan invasion of the Iowa lobe and the Illinoian invasion of the Illinois lobe, and that one lobe held nearly its maximum extent until the other culminated. The rela- tions of the two lobes of the lowan invasion appears to have been largelv a matter of conjecture, for it is now found that the Illinois lobe fell far short of reaching the limits assigned to it by McGee. It is doubtful if evidence has yet been collected by which it will be possible to demonstrate clearly either the space or the time relations of the two ice lobes. The space relations as well as time relations of the two lobes being still unsettled, the influence upon drainage is at best a matter of conjecture. The Iowa ice lobe appears to have reached as far east as the Mississippi River in southern Clinton and northern Scott counties. Possibly it reached a few miles beyond the river in southwestern Carroll, western Wliiteside, and northern Rock Island counties, Illinois, though such an extension is, as already noted, but weakl}^ supported. The Illinois ice lobe certainly extended a few miles beyond Sterling on the north border of Rock River Valle)^ and probably extended about to Geneseo, on the south border of that valley. The debatable tract east and south of Morrison, in central and southern Whiteside County, was apparently covered at the lowan stage, either by the Illinois or by the Iowa ice lobe. If the latter is found not to have extended beyond the Mississippi Valley, it would follow that this district was occupied by the Illinois lobe. The question of a coalescence of the two lobes, or the overlapping of their fields, depends, therefore, upon the determination of the extent of tlie Iowa lobe. If that lobe did not extend beyond the Mississippi, there would remain a strip about 8 miles in width along the east border of tlie Missis- sippi Valley which remained uncovered by ice throughout the lowan invasion. By including the valley its width woilld be increased to 10 or ' Eleventh Ann. Kept., U. S. Geol. Survey, p. 570. 2 Op. cit., PI. lA^II; mIso pp. r>70-r>77. THE lOWAN LOESS. 153 12 miles; it would embrace the belt of heavy loess west of Kock Creek, in Whiteside Comity, at the points where the lobes made theii' closest approach. A belt of this width would, when taken in connection Avith the valley of the Mississippi River, apparently have afforded an adequate line of discharge for the streams of the Driftless Area, and also for the waters issuing from the melting ice lobes. If, on the other hand, the Iowa lobe extended to the ^dcinity of Round Grove and Spring Hill, Illinois (see PL XII), and reached this culmination at the same time that the Illinois lobe had its maximum extension, there may have been a coalescence of ice for a breadth of perhaps 15 or 20 miles. This appears to re^iresent the extreme possibility of coalescence. Granting- such coalescence, it remains question- able whether a glacial lake could have been held in the region north of the junction of the lobes. The existence of Lake Hennepin appears, therefore, to rest upon exceedingly weak foundations so far as the influence of coalescing ice lobes is concerned. It is doubtful if a body of water of greater depth was present in the district north of these lobes than in the district south of them. It is generally supposed that the loess was deposited under conditions of very imperfect drainage, and that the districts which it covers were, in large part, under water for at least brief intervals. The extent and duration of the flooding, both to the north and south of the districts occupied by these ice lobes, is still largely a matter of conjecture, and a subject on which wide differences of opinion exist. With these remarks we pass to the discussion of the lowan loess. THE lOWAiy LOESS. DISTRIBUTION. Deposits of silt, tentatively classified with the loess and supposed to be of lowan age, cover the entire surface of the Illinoian didft so far as it lies outside the limits of the lowan and Wisconsin drift sheets, not only in Illi- nois, but also in Iowa and in States to the east as far as Ohio. These deposits have been extensively removed by stream erosion on a consider- able paii; of the slopes and in the valley bottoms, but still remain nearly intact on the uplands. They have been traced back several miles beneath the edge of the Wisconsin drift in central and eastern Illinois, but the full extent has not been ascertained. A portion of the Driftless Area in Illinois, 154 THE ILLINOIS GLACIAL LOBE. both in the northwest corner and in the southern end of the State, were ahnost entirely covered by loess, though possibly some of the highest knobs and ridges escaped. In northern Illinois, where the lowan drift sheet is exposed to view outside the limits of the Wisconsin, the loess-like silts are in-egularly dis- tributed. The Pecatonica lobe and the districts to the east, in Winnebago, Boone, western McHenry, and northern Dekalb counties, have scarcely any typical loess, and the silt deposits seldom exceed a depth of 1 or 2 feet. It is not certain that these deposits are of similar origin and date to the silt deposits on the west border of the lowan di-ift. In passing southward from the Pecatonica lobe loess-like silts overlap the lowan drift to a distance of several miles. In northern Lee County Illinois, they extend some miles east of Rock River. Upon approaching the Green River Basin sandy deposits appear which effectually conceal any silts which may have been deposited farther south. However, the belt of drift thought to be of lowan age that is situated on the south border of the Green River Basin is not sand covered. This has a much thinner deposit of silt than the lUinoian sheet to the south, and much of its surface seems never to have been coated with silt. Attention has been called to the existence of a tract neaidy free from loess in southwestern Carroll and northwestern Whiteside counties, Illinois, which may find its explanation in ice occupancy of the territory up to a date so late that the loess was barred out. There are quite extensive loess- covered tracts within this area, notably one which follows the Mississippi Valley. This belt of loess seems to be a continuation of the extensive belt which follows the west side of the Driftless Ai-ea throughout almost its entire length, and is perhaps somewhat later than the loess deposits made on uplands below the Driftless Area. Aside from this main belt along the Mississippi River there is a heavy loess deposit in northern Whiteside County, which is probably as old as the loess on the disti'icts to the east. Loess is also found on much of the narrow uplands lying between Rock and Green rivers from Spinng Hill southwestward to the junction of these streams. In addi- tion to the loess which is deposited in sheets there is in this region a loess capping the paha ridges. In some cases the paha are coated to a dejith of 15 feet or more, while bordering plain tracts are nearly free from loess. In other cases the loess appears to be nearly as henvy on the plain tracts as on the paha. The distribution in the lowan area is so irregular and patchv THE lOWAIT LOESS. • 155 that very detailed study is necessary to determine its limits. The general extent of the loess and associated silts may be seen by reference to the glacial map (PL VI). VARIATIONS IN THICKNESS. The variations in thickness of the loess apparently depend largely upon the relation (1) to the ice margin and (2) to the principal lines of drainage. On the margin of the lowan ice sheets, especially the one which occupied eastei'ii Iowa, there is a thicker deposit of loess than in districts remote from the ice margin. Also in Carroll and Whiteside counties, Illi- nois, there is a belt of loess extending from the hypothetical margin of the lowan ice sheet above outlined northward to the south border of the Pecatonica Basin and eastward to Elkhorn Creek, in which the loess has a thickness of 15 to 20 feet, while in the districts immediately north and east its average thickness does not much exceed 5 feet. The features here as well as elsewhere seem to indicate that the outwash from the lowan ice was much heavier within 10 or 15 miles from its border than at ffreater distances. The ice lobe which extended southwestward into northern Illi- nois has a less marked thickening of the loess near its border, though Mr. Hershey reports a perceptible thickening on the borders of the Pecatonica lobe. On the south border of the Green River Basin there is, however, a marked thickening of the loess at the line supposed to mark the southern limits of the lowan ice sheet. The thickness is nowhere much less than 25 feet and in places is fully 40 feet. Upon passing southward the thickness soon decreases to 12 or 15 feet, and about this thickness is maintained over much of the area between the Illinois and Mississippi rivers. The thickening of the loess along the borders of the main drainage lines is well illustrated by the Mississippi. On the borders of this valley in northern Illinois there is 25 to 40 feet of loess, but within 5 or 10 miles east of the bluff the thickness usually decreases to less than 10 feet. Following down the Mississippi, there is found to be a heavy deposit of loess on its immediate borders, passing through the area which was occupied or closely bordered by the lowan, as well as in districts to the north and south, a feature which seems to indicate that the loess deposition occurred after the withdrawal of the ice lobe to the west side of the rivei'. Upon passing into the district south of the limits of the lowan ice lobe the loess 15f5 THE ILLINOIS GLACIAL LOBE. decreases in thickness, especiallj" on the Iowa side of the river. From a thickness of 40 feet at Muscatine it decreases to but 10 or 12 feet at Burhngton and to about 6 feet at Fort Madison. On the east side of the river, however, the loess maintains a thickness somewhat greater than on the west, there being immediately opposite Fort Madison twice as thick a dejjosit as on the Iowa side. This extra thickness is perhaps attributable to wind, for along the eastern bluff of the river there are dunes composed of fine sand drifted by the wind from the broad bottoms. The prevailing wind being from the southwest, the dunes are found only on this bluff. The Illinois Valley is bordered both on the east and west below the mouth of the Sangamon River by heavy accumulations of loess, 40 to 50 feet or more. But upon passing back a distance of 5 or 10 miles from the stream, on either side, the thickness becomes reduced to 8 or 10 feet. The heavy loess of the Illinois and Mississippi valleys, tog-ether with a belt along the Missouri valley, continues down the Mississippi to the Gulf of Mexico. On the borders of southern Illinois the thick loess is confined to a belt but 5 or 10 miles in width, the thickness farther east being scarcely one-fourth as great as on the immediate borders of the stream. In central and southern Illinois the thickness of the loess seldom exceeds 10 feet and probably averages not more than 6 feet. The Kaskaskia, Emban-as, and other streams of south-central and southern Illinois do not have such heavy belts of loess on their borders as characterize the Illinois, Mississippi, and Missouri valleys. There is but little thickening u^jon approaching the Wabash River, the average thickness along the west bluff' of tlie stream being less than 10 feet. On the lower portion of the Ohio from near Rockport, Indiana, to its mouth, loess deposits are 15 to 25 feet in thickness, but above Rockport the thickness is seldom more than 5 or 6 feet, and this thickness prevails over southeastern Indiana and southern Ohio. STRUCTURE. The loess and associated silts are not so uniform in structure as might be inferred frojn some of the published descriptions. The earlier descrip- tions apply to a very porous deposit found on the borders of the large vallej's which was the first to attract the notice of geologists and which may be designated liluff loess. The great extent of the surface silt over THE lOWAX LOESS. 157 the plains between the streams has been known for only a few years. In the region under discussion the first recognition of the interfluvial silts as a deposit distinct from the glacial drift appears to have been made by Professor Salisbury in his studies on the borders of the Driftless Area in 1885 and in southern Illinois at a later date. The discussion of loess in the Illinois geological reports apply chiefly to the deposits on the immediate borders of the main valleys, though some recognition of its extent into the region about Springfield appears to have been made by Professor Worthen and his associates. The structure of the loess varies in vertical sections as well as from place to place. The leading vai'iations in the vertical sections are such as to support a threefold division : (1) The surface portion, 2 to 4 feet in depth, which has an earthy structiire due probably in part to the breaking down of many of the grains under atmospheric action. This phase charac- terizes not oidy the deposits on interfluvial tracts, but also those on the borders of the main valleys, as is natural if the earthy appearance is due to atmospheric action. (2) The main body of the loess, Avhich is a silt usually without definite bedding planes or stratification. It is somewhat more porous on the borders of the main valleys than beneath the interfluvial tracts. The variation in texture is apparently due to the removal of the finer material on the borders of the valleys rather than to the presence of coarser material there than in the interfluvial tracts. (3) The basal por- tion, which commonly shows a more distinct bedding than the body of the loess, and is in places sandy and pebbly. As a rule the pebbles are con- fined to the lower 2 or 3 feet, but in the thicker portions of the loess the well-defined bedding may occupy a depth of several feet. The pebbles often occur in jjlaces where the bedding is not distinct. Indeed, the most distinctly bedded portions are iisually almost free from pebbles. In following the loess from place to place across the interfluvial tracts it is found to undergo gradual changes in texture and color, for which a cause is not in all cases manifest. But as a rule the more porous portions of the loess are found in proximity to a large valley or to the border of the lowan drift sheet. Upon passing back from the valleys the open texture becomes less pronounced, and there is a gradual change to a clayey loam and then to loamy clay. A similar change in texture is found in ^jassing away from the border of the lowan drift sheet. This is well shown both in 158 THE ILLINOIS GLACIAL LOBE. southeasteni Iowa and western Illinois. In the vicinity of Iowa City,, along the borders of the lowan drift sheet, the loess is so porous that Avater readily penetrates it and tile draining is seldom necessary. But ujjon j^assing southward across Washing-ton, Louisa, Henry, and Des Moines counties, the texture becomes g-radually finer, and extensive areas in the southern part of the State require tile draining. In northeastern Missouri the texture is still more compact, so that a large portion of the rainfall is disposed of by surface evaporation. Similarly in western Illinois the loess of Henry, Rock Island, and Mercer counties is more porous than that of counties immediateh' south. But in this region the belt of porous loess along the Mississippi and that along the Illinois occupv so much of the interval between the streams that there remains onlv a narrow strip of compact loess in the vicinity of the divide. East from the Illinois River, as far as the divide between this stream and the Kaskaskia, the loess is sufficientl}^ porous to require but little tile draining. The Kaskaskia drainage basin and much of southern Illinois, like northern Missouri, has a surface silt too compact to absorb the rainfall. The loess in this region has become so puddled (perhaps because of the process of soaking and drying to which it has been subjected) that underdrainage is difficult. Through- out much of the region a hard ferruginous crust immediately underlies the soil at a depth of 12 to 15 inches or less, which needs to be broken before underdrainage can be established. The compact silts of southern Illinois present an ashy appearance near the surface, which gives them the name of "white clay." It is rare to find even an inch of black soil on their sur- face. In this respect they are in striking contrast to the silts west of the Kaskaskia Basin, in which a black soil several inches in depth is generally present. The white clay district is continued eastward into Indiana and southwestern Ohio, occujjying much of the interval between the glacial boundary and the southern edge of the Wisconsin drift sheet. The mineralogical constitution of the loess and determinations of the size of its grains has been given considerable attention ])v SalisburA", and the results are presented in the Sixth Annual Report of this Survey. The samples selected were chiefly from localities adjacent to the Driftless Area on each side of the Mississij)pi. It was found that of 150,s . to !N O o °l ' « ti §1 o ^! ^ _. -* 1 O O CO t^ OJ c CO ""^ Ph O O rH -i 00 .- 8 r-; 00 O Ph in -" ^ ^ «=§ Sd (.M o o o CO O l> t-T -= 2 +i CO o o « <^ CC ^ tn g fn f!-> O) in (M t- c «> 3 PM ^ ^ ^ ^ o o f_ o 1 • 9 = W «3 a =3 IT o o s rt faD 3 o t~ IM" S.S o ■i^ 3s g o o o o OC -* in OC O) D C = CO d- PM a d ;3 11^ 1 <0 a 3 a) i; ;; .S g 5 i 'S a J- p o > P3 a to a : If i i RE z IT c r- H C = c :> 5 1 'IS fa EH E-i O fk ■ o 05 • ^a a n ■-< (- ■;3^ o* -^ O O Ol 1 o o o o o c ^ o 1 = o o o c: 3S u CO o O O 1 CO .s-§ p< • d" d" d" d 1 d" «3 a =3 m (D (M O CO a a r-l O O O 1 CJ Mo -" t- in <=! CO u '^ M CO C-- 1 C~ fc-M ■-H CI t>7 O ™-|c,- 1 *i o o o o in i^ -* O 1 CD 'tji c O) a o o o o m 02 00 rH (M t- QO,^ o o" c d oo o 'I- I- en o o ^ ;::;:! ss 3 35 £ >. ooo-^ooool-i* i-H O O O O 1 .-1 O 1 CI O O O CM ca (0 p* - oT d" d" d" o)' m a CO i-H O C3 -rf ■g« ^,-10= c- >00 "3 ^ t-T -qT irf «3 n] ta r-l W OC t t- ■^ o 1 l> 13 |1 1 _J ooo— looino^oa — O C' a OOOOCOCOWr- iM t> c: CO doodt^^ci|nj^u- 1 - 1 tH CO iD li ^ 1 ^ ooeo Doooool-— 1 CO O O O O -)< 'o [M rH O O O 1 CO tn r-T d" d d" t-^ m a a 1 in c^ bo rH t> l> 1 O u l-H '^ 1 CD O in 1 in 1 - 00(MC-t-CO t- C^ O (M ,? ddddW'-JoJc- i W5 Tl d "-* o (N in H O) o P3 rH © " (S 1 O O CD - - o o o c 3 t^ °^inoooc 3 in (D fc: O O O O C 5 o S ?" Pi • rH CO" d" d" C «>a -rH CO o c = d ? 0) in cj CO c 5 1-H J3J3 C c3 ^ 2 •r- f-l I— o ■3 ^ - CO rt bjD 1 CO C5 rH C 3 D- S d" a2_ -«i 00-*"*(N.C50"- *< OJ r- i* c 5 to a OOOt-r-<'*a?-' H t- D ) c: - o S's S d d d d d .-h" i>-' - *" ^ u 3 C i in CO '" CO -r H 0> C Lj OJ PM . di ? . m u a B ' ■i '■) c3 CO a 3 OT J a o o i 2 o : p 2 5 3 'S S2 ra—i 2 ■ 1^ j 3 a >> n -i in = . o t! • in i- rt r jij" _l^ D 3JD s fl " a c <1 T- n ■M r ■; => =1 C 5 y- ^ 1 MON XXXVIII- -11 162 THE ILLINOIS GLACIAL LOBE, Table III. — Upland loess, pervious to water. Diameter in millimeters. 2-1 1-.5 .5-. 25 .25-1 .1-.05 .05-. 01 .01-. 005 .005-. 0001... Conventional names. Fine gravel Coarse sand Medium sand .. Fine sand Very fine sand . Silt Fine silt Clav Total mineral matter . Organic matter, water, loss. Loss by direct ignition . (1328) 'Wyomingsoil, 1-15 (1307) Carrollton soil. 1-15 inches. inches. Per cent. Percent. 100. 00 100. 00 6.14 Grains per gram. 1 57 180, 500 13, 890, 000 153, 000, 000 10, 970, 000, 000 (1308) Carrollton subsoil, 24-44 inches. Per cent. 0.00 0.10 0.87 1.00 6.17 62.58 8.76 12.52 100.00 4.16 Grains per gram. 2 129 1,462 114, 600 18, 170, 000 162, 700, 000 5,916,000,000 11, 137, 070, 558 | 92. 00 : 6. 096, 986, 193 , [ 8.00 ; Table IV. — Upland loess, almost impervious to water.''- Diameter in mil- Conventional names. (1321) Greenville soil, 2-15 inches. (1342) Northern Cum- berland County soil, 1-12 inches. (1345) "Western Jeffer- son County soil, 2-15 inches. (1343) Moweaqua *5il, 2-18 inches. limeters. Per cent. Grains per gram. Per cent. Grains per gram. Per cent. Grains per gram. Per cent. Grains per gram. 2-1 Fine gravel Coarse sand Medium sand 0.48 1.92 1.22 0.58 5.08 59.06 11.09 14.12 1 35 178 65, 130 92, 790 16, 870, 000 202, 100, (100 6, 564, 000, OOO 0.30 1.05 3.42 3.30 6.47 55.48 11.70 14.90 1 18 483 4,595 114,400 15, 340, 000 206, 900, 000 6,707,000,000- 0.00 0.07 0.29 0.40 6.38 56.92 12.18 1 42 577 116, 900 16, 290, 000 221. 800. 000 0.00 0.08 0.77 0.11 4.88 52.50 12.15 1-.5 .5-. 25 25-. 1 1 113 13, 110 .1-.05 .05-. 01 Very fine sand Silt 89,280 16, 020, 000 01-. 005 221.600.000 .OO5-.O001.. Clay 17.06 7,948,000,000 22. 10 10, 300, 000, 000 Total mineral matter Organic matter, vrater, loss 93.54 6.46 0, 783, 128, 134 96.62 3.38 6, 929, 359, 497 93.30 6.70 6, 186, 206, 520 93.39 6.61 10, 536, 722, 504 100.00 5.59 100. 00 3.11 100. 00 100.00 5.73 Loss by dir 4.49 ^Professor TTdden states that the coarse particles found in these samples are usually concretions of iron oxide, instead of sand grains or pebbles. It is probable that the sand seldom exceeds the diameter .25-. 1, or the grade called fine sand. ANALYSES OF BOWLDER CLAYS, ETC. 163 3 fe o o o o c 3 O CO P p g T-l Ol .-1 C (D DO t- tD C 3 '^ a g 1"' ■*' It O^ 1 § .Hi-l(O(OiO0DlOC Cl t4 (M V ■* Cf _ VI a, 1 OOiOMOOOC o' m o o c Poo ^ ^' = i •^ H " Mo o: l^ OOOOOO'-l'Csitf !:i*-3 s -* r- ■r fc r3 " 2 2 s= — o £ -* I- o> o o c 1 ^P \r p i-H 00 00 C ;: ?s ^ oc o '^ 4i P 9 SPSSSSSS M OO 00 ^ ^ O C: CO -* t- >-« CO c^ CO CD -Tj> fH CS a. •s v !^fl COrP 1^ R t^ 2- CO 00 c: C^l Qt .£100 Q7 '"' CO « oo c a ■M t- -* in eo o o ' tj « c rH ~ a « p n o TZ p s 11 he a r. s S C i E X '? S p o o r = 1 [- i ■J a c > c "i 1 1 '5 bJD Z •"i ©5 "s B c r- a| \r ^ fla -7 "" \r ^ ^ - (= u § '- o S P3 EH ce a □ a Br'i 4i p in'E P <£ O O O O o - • ^- _ SOS fc T~t ~H ^ C-. ^^ Pm 3 . Li ■= s m a 1^ •g& o rSjs CD -»i ifiS ^^ f^ -SoS L. <= pJ-W" P* ■ CO O (N 00- C r- (M S &: O O P P E^ *3 bo in ir C^J W O OL CT a-^^ 2) S ver ock chea to CM C^ <£ -* ffi t- "1 ir ■^f* P (N CO ir CO o cc P- Ic^ ?SrtP^.9 '"' ^ ^ from oms ouis, t- ■^ <= o P. - umbo bott St. L ches. cn a if. (M a a S •g^ C^ s £ % ?-£«^.a o ■s.&s^ 4i O O CO a> rr oc rv (M o o c a C^ Cf a- 1340) Mis nea soil !^ ^ fe -» ^ Ph oS nr P. • St CO rn rr, <-l o O 00 M CD a »n CD o rtoo C5 o; -^ 4= CO MlH CD Ph a o 'C c p g p o lii [^ o ^ P ffl CO <0 p p > a) 'a 1 a C 1 p o 'p _fcJD H to e £ a f4 i f5 fa o M^ lA as p a 1 1 tn ^i r^ o o s 6 164 THE ILLI2«J^OIS GLACIAL LOBE. Several cliemical analyses of the loess have been made which repre- sent its structure at widel}^ different points. The first four analyses in the table below were made by R. B. Riggs, of the U. S. Geological Surve}^, in connection with Chamberlin and Salisbury's study of the loess bordering the Driftless Area, and were published in their paper in the Sixth Annual Report of this Survey. No. 1 was taken from the summit of a ridge in the suburbs of Dubuque, Iowa, at a point about 300 feet above the Mississippi River. No. 2 represents a 7-foot stratum of loess lying over brown residu- ary clay near Galena, Illinois, at about 350 feet above the Mississippi River. No. 3, from Kansas City, Missouri, was chosen as a representative of the most pronounced loessial characters at that locality. No. 4 was taken from aear the center of Vicksburg, Mississippi, about 200 feet above the Missis- sippi River, and probably fairly rejjresents the upper half of the stratum there, but not the lower portion, which seemed heterogeneous. The remain- ing two analyses were made by Prof. W. A. Noyes for Dr. J. T. Scovell, and are published in the Twenty-first Annual Report of the Indiana Geo- logical Survey. They are designed to illustrate the constitution of the white clay east of the Wabash River, near Terre Haute, Indiana. No. 5 represents the subsoil, the sample being from a depth of about 22 inches. No. 6 represents a sample from a depth of only 10 inches. The samples analyzed by Mr. Riggs were dried at 100° C; those analyzed by Professor Noyes at 135°. Table of analyses of loess. SiO, A1,0:,.... Fe.O, .. FeO TiO: ... P2O.',.... MnO ... CaO.... MgO ... Na;0.-. K,0.... H;0 (a) CO,.... SO3 C No. 1.— Da- buque. 72. 68 12.03 3.53 .96 .72 .23 .06 1.59 1.11 1.68 2.13 2.50 .39 .51 .09 No. 2.— Ga- lena. 64.61 10. 64 2.61 .51 .40 .06 .05 5.41 3.69 1.35 2.06 2.05 6.31 .n .13 N0.3.— Kansas Citv. 74.46 12.26 3.25 .12 .14 .09 .02 1.69 1.12 1.43 1.83 2.70 .49 .06 .12 99.78 100. 21 99. 99 i (r(.'uulains H of orjiaiiir tiiattur in Noa.1-4. No. 4.— Vicksbarg. 60.69 7.95 2.61 .67 .52 .13 .12 8.96 4.36 1.17 1.08 1.14 9.63 .12 .19 99.54 No. 5.— Near Terre Haute. 72.87 11.25 6.75 .95 .69 1.06 .39 2.26 4.24 No. 6.— Near Terre Haute. 79.77 9.95 3.39 .70 .67 .26 1.08 2.05 2.55 100. 44 100. 42 THE lOWAN LOESS. 165 FOSSILS. From the time of the earliest recognition of the loess in the Mississippi Basin the presence of fossils has been mentioned as a peculiarity of the deposit. These fossils are present, not as ingredients of a mixture, like the wood or other organic remains found in bowlder clay (whose life was inde- pendent of the deposits in which they are embedded), but as a fauna repre- senting the life of the region during the progress of the accumulation of the deposit and dwelling ixpon it or in it. The loess fossils are found in greatest abundance along the immediate borders of the main valleys where the loess attains its greatest thickness, notably along the Mississippi, the Illinois, and the Wabash. They occur from the top to the bottom of the deposit and bear clear evidence of having lived during its deposition. Along the smaller valleys of the region they are rarely found. On the interfluvial tracts but few fossils have been found at a distance greater than 5 miles back from the borders of the main valleys. The most notable exception is in the thickened loess border south of the Green River Basin, where the loess is thought to have been deposited along the lowan ice front, though here they are far less numerous than along the main valleys. Fossils are also distributed more widely along the Sangamon than along other tributaries of the Illinois, being found as far back as the vicinity of Springfield. .The cause for the scarcity of fossils along the small streams and in the interfluvial tracts can as yet scarcely be decided. It is not known whether they have been destroyed there by subsequent leaching and weathering or were never present. Professor Shimek, as indicated more fully below, has found that in eastern Iowa the living representatives have about the same distribution in relation to streams as those embedded in the loess, and he infers that the loess fossils were never present in abundance at a great distance from the main valleys. The most abundant and widely distributed fossils are mollusks, of which terrestrial species predominate over aquatic. By far the most com- mon mollusk is Succinea avara, a form which is now found in swampy places as a rule, but which occasionally occurs in dry situations. Shimek regards. this as a strictly terrestrial rather than a semiaquatic form. The tables given below serve to indicate the proportion of species of terrestrial and aquatic forms. The shells of a few unios and other strictly fluviatile 166 THE ILLINOIS GLACIAL LOBE. mollusks have been reported from the loess, but closer investigation tends to render doubtful their occurrence in unmodified loess. In other cases, notably in the deposits near Freeport, from which collections have been made by Hershey, the relation to the loess is not clearly determined and the deposits may prove to be entirely independent of the loess deposition. Concerning the mammalian remains reported from the loess, it is neces- sary to state that their relation to the loess deposition is, in most if not in all cases, very vaguely determined. The remains of a mammoth, found near Davenport, and reported by W. H. Pratt, ^ were apparently from near the base of the loess and just above the Sangamon soil, which is there rep- resented by a bed of peat and soil 3 feet in thickness. Possibly the remains were derived from the Sangamon soil horizon and redeposited in the basal portion of the loess. The remains of a deer are reported by Witter^ to have been found in the loess near Muscatine. A fine fragment of the jaw of a mastodon is reported by Worthen^ to have been found just above the city of Alton, Illinois, beneath 30 feet of loess, and separated from the underlying- limestone by 2 or 3 feet of local drift. Worth en also reports* the occurrence of the remains of extinct mammalia in brown clays overly- ing the limestones, as well as in the crevices of the limestone in the driftless region of northwestern Illinois. Whether these are beneath or within the loess deposit which covers that region has not been ascertained. As yet the molluscan fossils have been collected and specifically identified in but a few localities within the region under discussion. Since there is some variation from place to place, the identifications of each locality are represented. Those in List 1, from Savanna, Illinois, repre- sent the fauna in the southern portion of the Driftless Area. In addition to these, Helicodiscus lineatus Anth. has been found near Galena and Lim- nopliysa humilis Say has been found on the heights east of Prairie du Chien. These are thought by Salisbury to be in unmodified loess, and are separated from a list of fossils found in the terraces of streams traversing the Driftless Area.^ 'Proc. Davenport Acart. Sci., Vol. I, 1876, pp. 96-99. Also Geol. of Iowa, by C. A. White, Vol. I, 1870, p. 119. '^Proc. Iowa Acad. Sci., Vol. 1, 1880, p. 16. Also Eleventh Ann. Kept. U. S. Geol. Snrvey, 1890, p. 471. »Geol. of lUiuois, Vol. I, 1866, pp. 38 and 315. ■■ Ibid., p. 39. '■•Sixth Ann. Rept. U. S. (Jeol. Snrvey, pp. 28;") iind 286. LOESS FOSSILS. 167 The Davenport fossils are apparently from the unmodified loess along the west bluff of the Mississippi, as are also those from Burlington, Iowa. The list from Moline, Illinois, is from specimens gathered on the level upland lying between the Rock and Mississippi rivers. A loess-like silt carrying fossils has been found beneath the glacial deposits in that vicinity. The fossils, so far as identified in this lower silt, are strikingly similar to those found in the surface deposit. The list from Muscatine, Iowa, contains, in addition to the usual loess fauna, several species of Unio. Unfortunately the evidence is not clear concerning the condition of the bed of loess in which these Unio shells was found. It is Professor Witter's present opinion that the loess had suffered some disturbance, thus leaving it an open question whether the shells are as ancient as that deposit. The fossils noted in the list from near Freeport are stated by Hershey to have been secured from under a bed of loess in a blue-green silt, separating the loess from the underlying gravel. He further states that the gravel is made up in part of erratics, and is, therefore, not preglacial in age. This gravel and the overlying silt are described by Hershey under the name "Florencia formation,"' and are referred to an interglacial stage between the loess deposition (which he correlates with the lowan glaciation) and a preceding- period of glaciation now provisionally referred to the Illinoian. It is stated that great care was taken in securing the shells, because it was early recognized that a fauna of very similar facies occurs in the modern alluvial deposits of that region. It is also stated that this blue- green silt is overlain with perfect conformity by the basal member of the lowan loess series, a feature which leads the present writer to question whether it should be separated from the loess series. However, the striking contrast between the fauna of this deposit and that usually displayed by the loess and the striking similarity to the alluvial fauna of that region, should have weight in determining the classification. Thte list from Virginia, Illinois, is made up entirely of a collection in the office of Dr. J. F. Snyder, at Vii'ginia, who also made the identifications. 'Amer. Jour. Sci., 4th series, Vol. IV, 1897, pp. 90-98. 168 THE ILLINOIS GLACIAL LOBE. Lists of loess fossils. Names heretofore commonly uaed. Names in Pilshry and Johnson's check list of terrestrial mollusks for 1898. List I. From Savanna, Illinois.- Patula Striatella (Anth.) Morse... Pyramidula striatella (Anth.) (Collected by R. D. Salisbury Pils. and identified by R. E. Call.)a Patula strigosa var. C o o p e r i Pyramidula strigosa iowensis W. G. B. Pils. Succinea avara Say . Succinea avara Say. Succinea obliqua Say. Succinea avara .Say. Succinea obliqua Say. Helicina occulta Say. Leuchocheila fallax (Say) Try. Pyramidula striatella (Anth.) Succinea obliqua Say List II. From Davenport, Iowa. (Reported by W. H. Pratt.) i Succinea avara Say Succinea obliqua Say Helicina occulta Say Pupa fallax Say Patula striatella (Anth.) Morse... Pils. List III. From Davenport, Iowa. (Collected by J. A. Udden; identified by C. T. Simpson.) Succinea avara Say - Succinea avara Say. Succinea luteola Gld. Succinea luteola Gld Succinea lineata ? W. G. B Succinea grosvenorii Lea. Ferussacia subcylindrica (L.) Cochlicopa lubrica (M ii 1 1.) Biun. P. & J. Patula striatella (Anth.) Morse . .. Pyramidula striatella (Anth.) Pils. Helicodiscus lineatus (Say) Morse. Helicodiscus lineatus (Say) Morse. Helicina occulta Say Helicina occulta Say. Sphyradium edentulum alticola (Inger.) P. -as wells on James Barnett's farm shows & an interesting series of drift sheets separated by buried soils, as follows : Section of a gas u-eJl in drift near Clinton, Illinois. Feet. 1. Soil anil yellow clay , 15 2. Blue clay 30 3. Black soil, with wood 3 4. Drab clay _ y 5. Black mold and driftwood 8 6. Drab-colored day 20 7. Driftwood (log?) 2 8. Drab-colored clay ■ 21 9. Hardpan 12 10. Drab-colbred clay _ J 11. Greenisb clay _ lo 12. Saud, etc 5 Total ~^ In this section it is probable that only 1 and 2 are to be included in the Shelbyville drift. Number 3 apj^ears to be the Peorian soil Avhich caps the loess in the region outside the moraine, while 4 probably represents the loess and 5 the Sangamon soil between the loess and Illinoian drift. In the vicinity of Atlanta the drift has a known tliickness of over 200 feet. Records of several wells were obtained which range from 125 to 210 ' Geology of Illinois, Vol. VIII, p. 34. 'Published in the Geology of Illiiioi ) Geology of Illinois, Vol. VIII, pp. 58,59; al.so p. 13. 206 THE ILLINOIS GLACIAL LOBE. feet ill depth, and none of tlieni reached the rock. They penetrate about 100 feet of soft till of hlue color, probably referable to the Shelby ^alle sheet, beneatli which a harder, brownish -blue till is entered, which seems referable to the Illinoian drift. The village of Atlanta obtains its water- works supply from two 8-iiich Avells 151 feet in depth. The following detailed record of the drift beds penetrated was furnished by J. S. Bevan, mayor of Atlanta: Section of a trell at the iratericorln at Atlanta, Illinois. Feet. Black soil 3 Yellow clay 13 Blue clay 10 Gray saiul aud gravel - 10 Blue clay - 2 Sand aud gravel 9 White clay and sand 7 Blue clay with gas 3 White sand aud gravel 10 Sand - 6 Dry sand aud gravel with gas 13 Blue clay 1 Clay, sand, gravel, aud gas 16 Hardpan - 9 Black drift dirohably Peorian soil) 6 White clay (probably lowan silt) 2 Green clay (probably lowau silf ) i Hardpan (probably Illinoian till) - -. 10 Gravel and water 12 Total - 151 The black drift noted in this Avell section has about tlie level of the plain outside the Shelby ville drift sheet, and is probably a soil formed above the lowan silt. In the ^'icinity of Dela^-an the drift over an area of several square miles may exceed 300 feet in depth, for the Shelbyville sheet here encroaches on a preglacial valley; the thickness in one well is 313 feet. The city Avaterworks well is 'l-iO feet in dei)tli and has tlie following section, furnished hx J. I). Mount, citA' marshal: Section of the a-cll at n-atcra-orhs in J)elaraii, Illinois. I'cut. Yellow bowlder clay (Shelliy ville sheet) 15 Blr.e bowlder day (Sbelbyvillo sheet) 60 lilack 111 lick with wood (probably Peorian soil) 6 Solt green clay (probably lowau silt) 8 Hard gray bowlder day (jirobably Illinoian till) SO Gray sand containing water 122 Total 240 THE SHELBYVILLE MOKAII«fE. 207 The black muck penetrated in this well is at the base of the Shelb}-- ville drift sheet. Mr. Mount reports that several wells in the vicinity of Delavan have encountered a similar bed of muck at this horizon. Attention was called above to exposures along- the Toledo, Peoria and Western Railwaj east of Peoria, and also on the east bluff of the Illinois opposite that city, where the Shelbyville sheet is underlain by a bed of fossiliferous loess similar in texture and in age to that found on the surface of the lUinoian drift outside the limits of the Shelbyville drift sheet. The loess is 8 to 12 feet in thickness, or about the same as on the uplands outside the Shelbyville sheet. It occurs at a corresponding elevation of about 200 feet above the Illinois River. Beneath it there is exposed full}- 100 feet of the older drift sheet. The thickness of the Shelbyville drift sheet above this loess varies greatly, being in places but 20 feet, while elsewhere it is 75 or 100 feet. The variation is due in part to erosion and in part to original inequalities of thickness. As previously noted, these exposures afford excellent opportunity for contrasting the Shelbyville sheet with the older drift and for studying soils formed on tlie surface of the older drift. In the portion of the Shelbyville moraine west of the Illinois River there are several wells 150 feet or more in depth which penetrate a blue till until the level of the base of this drift sheet is reached. . In places its depth is more than 100 feet, and seldom does it fall below 70 feet. A large well was dug by William Dickison on the crest of the moraine 2J miles west of Alta. The well entered blue till at less than 10 feet, winch continued to a depth of 117 feet. Here a very bowldery bed 4 feet in thickness was passed through, under which a bed of loess was found, specimens of which were examined by the Avriter. Beneath the loess there is a hard pebbly claj-, apparently lUinoian till, alternating with sand beds. Gravel con- taining water was . struck at a depth of 156 feet. A well made by John Holmes, jr., one-half mile west of Alta obtained an abundance of water at 125 feet in gravel Ijelow till. But a boring made for John Holmes, sr., 1 mile east of Alta failed to obtain water, though it reached a depth of 370 feet. It apparently did not strike rock, but terminated in a fine sand. A bed of muck with -^^-ood and leaves was found at the remarkable depth of 245 to 247 feet. The sand below the muck is perhaps an allu^nal deposit of pre-Illinoian ag-e. In the -sdcinity of Dunlap the best supply of water is obtained at 100 to 112 feet, in gravel and sand associated with the older drift. In the 208 THE ILLINOIS GLACIAL LOBE. village the base of the Shelbyville drift sheet is reached at fi5 or 70 feet, and a few wells are obtained at this depth. A well at Harrison Harlan's, 2 miles south of Dunlap, at a level about 40 feet lower than the village, has a depth of 117 feet. It is mainlj^ through the older drift, which is largely till, and Avater is obtained in sand and gravel at the bottom. CHARACTER OF THE OtTTWASH. Considerable attention has been given the deposits and valley terraces immediately outside this drift sheet and on its outer slope in order to ascer- tain the character of the outwash. It is found that silt deposits, as well as sand and gravel, cap the surface of the outer face of the moraine and extend out onto the border plain. Tlie silt depo.sits are loess like and fos- siliferous, and suggest a feeble drainage. The sand and gravel deposits are very limited in tlieir extent, and, on the whole, favor the view of feeble drainage. The amount of coarse outwash is very much less than is found to characterize the Bloomington morainic system, as is shown farther on. In some portions of the border the close association of silt and gravelly out- wash renders the interpretation somewhat puzzling. The features can per- haps best be set forth by giving attention to each valley in turn which leads away from the Shelbyville sheet into the outer-border district, beginning with the Wabash Valley and proceeding westward. In the vicinity of the Wabash Valley the Shelbyville drift sheet is found to be generallv coated to a depth of several feet with a yellowish loess-like silt. This is especially well shown on the west side of the valley in the vicinity of St. Mary's, Indiana. This silt is better developed on the border of the river than at points a few miles back, there being scarcelj^ enough silt in the latter situation to conceal the bowlders which cap the till. The distribution of the silt seems such as would be expected if drainage conditions Avere inadequate to carry off the water from the melting- ice. There are, however, other features which seem to indicate good drainage conditions. At the point where the moraine crosses the river, near Ather- ton, a gravel })laiu is liuilt up to a, height of about 75 feet above the present stream, whose surface carries basins such as occur on gravel plaii\s or ter- races leading awav from a niorainc, aud -avv found ouIa" near the moraine. Tliere is at least a. suggestion tltat this gravel plain is to l)e correlated with the Shelbyville moraine. This V\e\v is strengthened 1)}' the fact that the THE SHBLBYVILLE MOEAmE. 209 material is very coarse at this point compared with that above or below, there being many bowlders, as well as cobblestones, embedded in the gravel. Were there no basins, the coarse material found in this portion of the terrace might be explained as a product of subsequent streams working upon the portion of the Shelbyville moraine which had been laid down within the valley, but the basins favor the view that this portion of the terrace is the product of the headwaters of a glacial stream. The removal of fine material from this terrace seems to indicate that there was good drainage at the time it was forming, a view which does not readily har- monize with the silt deposition along the valley. Passing west to the Embarras Valley, which leaves the Shelbyville drift near the line of Coles and Cumberland counties, one finds evidence of a moderate discharge of water down the valley. The outer face of the moraine contains knolls of gravelly constitution in the immediate vicinity of the Embarras River, and among these knolls there are plane-surfaced tracts of gravelly material having the appearance of being the dejjosit of streams issuing from the ice margin. On the immediate borders of the Embarras Valley there is still better evidence of glacial outwash. Gravel deposits foi'm a sheet which caps the till to a depth of several feet and which declines rapidly from the crest of the main ridge southward to the plain outside the moraine, occupying a very shallow valley in the passage down the slope of the moraine. Remnants of this gravel, preseiwed along the brow of the bluffs, stand 90 feet above river level at the northernmost point noted (2 miles north of the county line), and but 70 feet opposite the ford at the county line, and 45 feet at the south edge of the moraine about 2 miles farther south, and 35 feet above the river at the oxbow curve a mile farther south. The rate of descent is, therefore, about 10 feet to the mile more rapid than that of the present stream. At the north the gravel over- wash stands 35 feet above the level of the base of the Shelbyville drift sheet, whose limits are here well defined by a white clay such as caps the older drift outside the Shelbyville sheet. At the south border of the Shel- byville drift the surface of the gravel stands 25 feet below the level of the white clay; it therefore cuts right down across the plane of the white clay. The valley of the Embarras above the south edge of the Shelbyville sheet has probably been excavated entirely since the Shelbyville drift was MON XXXVIII 14 210 THE ILLINOIS GLACIAL LOBE. deposited. The depth of the gravel deposits on the outer face of the Shel- byville moraine is but a few feet, seldom so much as 15 feet, and the gravelly belt, including the knolls as well as plane-surfaced tracts, has a width of scarcely more than 2 miles. The gravel has been carried but a few miles south of the limits of the moraine, there being only sand from the vicinity of Greenup southward in the terrace remnants found along the valley. These terrace remnants stand 20 to 40 feet below the border ujjlands and have apparently been built up at least from the level of the stream, 25 feet or more. The moderate transportation of gravel seems to indicate that the discharge was not vigorous and that drainage conditions were rather imperfect, except on the slope of the moraine. Passing westward to the Kaskaskia Vallej^, which leaves the Shelby- ville drift at the city of Shelbyville, one finds that the valley below the border of the moraine contains scarcely any deposits coarser than sand in the terraces built up during the Shelbyville or later stages. Light deposits of gravel were found on small tributaries at the points where they leave the Shelbyville drift sheet, but these are only a few feet in depth and are not, as a rule, continued down to the river valley. Within the limits of the moraine immediately above Shelbyville there is a terrace standing about 25 feet above the river which contains gravel and cobble. In places the gravel and cobble are found to rest upon till and to have a depth of but 8 or 10 feet. In other places the gravel apparently extends to the underlying shale, which, as shown by the bridge piers east of Shelbyville, sets in at 15 or 20 feet below low water. It is not entirely clear that this gravel and cobble was formed as an outwash from the ice sheet at the Shelbyville stage. On the contrary, it seems quite as probable that it is a residue resulting from the cutting down of the valley since the Shelbyville stage. In the process of cutting down, the coarse material would become concentrated while the fine material would be transportod down the valley. In liarmony with this view it is found that the surface of the terrace is somewhat below the level of the Shelbyville drift sheet and occupies a valley cut in that and the older drift sheet. The evidence from this valley, therefore, indicates a fee])le outwash from the ice sheet at the Shelbyville stage. The next valley of importance leading away from the Shelbyville drift sheet is that of the Sangamon River. Along this valley from the edge of THE SHELBY VILLE MORAINE. 211 the Shelbyville sheet down as far as Springfield the terraces are composed of a gravelly sand with a few large pebbles. It is not certain, however, that these terraces should be correlated with the Shelbyville drift sheet, for they seem to be quite as well developed above the point where the river leaves the moraine as they do below that point. As indicated farther on, these deposits may be correlated with the Cerro Grordo moraine. At the point where the river crosses the Shelbyville moraine, south of Decatur, and also south of Harristown, the terrace remnants are found to lie in a valley cut to considerable depth into the Shelbyville sheet, and no over- wash gravels were found at higher levels. It should be stated, however, that, owing to the absence of wagon roads following along the valley and the inclemency of the weather at the time the writer was there, the valley was examined only at the two road crossings south of Decatur and south of Harristown. Further study at intermediate points or below Harristown may bring to light gravels which can be con-elated definitely with the Shelbyville moraine. Along the valley of Salt Creek, the first stream of importance issuing from the Shelbyville moraine north of the Sangamon River, a light deposit of gravel was found immediately outside the moraine on the road between Kenne}^ and Hallsville, but the main deposits of the terraces along the valley are sand. This stream, like the Kaskaskia and Embarras, seems, therefore, to have carried only a weak discharge at the time the Shelby^dlle moraine was forming. Two tributaries of Salt Creek — Kickapoo Creek and Sugar Creek — which cross the Shelbyville moraine farther north than the main creek, have their sources in the Bloomington morainic system and carry terraces, whose head is found in that moraine. The valleys were not given sufficient study to enable the writer to determine whether they also have terraces which may be connected with the Shelbyville moraine. If such terraces are present, they are far less conspicuous than those which head in the Bloomington moraine. On the Mackinaw River a terrace has been traced into connection with the Bloomington drift sheet, but none has been found which can be corre- lated with the Shelbyville. A deposit of loess several feet thick caps the Shelbyville moraine in the interval between the Mackinaw and Illinois 212 THE ILLINOIS GLACIAL LOBE. rivers, aud also farther nortli and south, which, as above noted, seems to have been derived from the Shelbyville drift rather than brought by wind from the plain of lowan loess on the west. On Farm Creek, which enters the Illinois River opposite Peoria, and on small western tributaries of the Illinois just north of Peoria, as well as on the borders of the Illinois Valley in the vicinity of that city, there are gravel deposits which it is thought are derived in the main from the Bloom- ington moraine, though some of the deposits west of the river may prove to be connected with the Shelbyville. Those along- Farm Creek may be traced with but slight interruption eastward into connection with the Bloom- ington moraine. These gravel deposits have a remarkably high altitude above the Illinois Valley, their elevation being about 175 feet above that sti-eam on each side of the Illinois Valley at Peoria. It would seem, there- fore, that the Illinois and its tributaries have been cut down this great amount at the point where the Shelbyville moraine crosses the river, since the Shelbyvalle stage, and probably since the Bloomington. However, the valley was apparently filled here to a greater height than at points above and below. A view of the gravel at Peoria is given in PI. XIII. It is of medium coarseness, and in this respect harmonizes with that usually found in terraces that head in the Bloomington morainic system. It is coarser than is commonly displayed by the terraces that head in the Shelbyville diiffc sheet. Kickapoo Creek and its tributaries, which lead away from the Shelby- ville moraine in northern Peoria County, have terraces of sandy gravel which are doubtfully refeiTed to the Shelbyville stage. They may prove to be simply incidents in the cutting down of the valleys through the some- what sandy drift deposits outside the Shelbyville moraine. There appears to be no gravel teiTace along Kickapoo Creek that can be correlated with the Bloomington moraine, though the stream heads in that moraine. In view of the evidence just cited concerning the character of the out- wash, it appears that in general it was weak, and it is doubtful if a vigorous outwash at any point can be proved. THE SHELBY VILLE MORAINIC SYSTEM. 213 INNER-BORDER TRACT. TOPOGRAPHY. The topography for some distance north and east from the border of the Shelbyville drift is of a gently undulating type, not markedly different from that of the thickened border. North and west from the Sangamon River there is a triangular tract included between the Shelbyville and Bloomington moraines in which swells 10 to 30 feet high are not uncom- mon, but no well-defined morainic belt has been found. East from the Sangamon River there are several small drift ridges lying between the Shel- byville and Bloomington moraines, but the greater part of the surface is plane. Aside from the ridges, the surface is les? undulating than in the tract west of the Sangamon, just mentioned. These ridges are discussed individually and in some detail farther on. THICKNESS OF DRIFT. The Shelbj^ville till sheet covers this inner-border tract to a depth gen- erally of 50 or 75 feet, and in places 100 feet or more. The depth seldom falls below 50 feet. It is usually not difficult to ascertain the thickness of the Shelbyville sheet, for well drillers report that it is much easier to pene- trate than the underlving* older drift. In • the detailed discussion which follows, these differences are set forth. STRUCTURE OF DRIFT. In the district west of the Illinois River the Shelbyville moraine is separated from the Bloomington moraine by a narrow lowland, nowhere more than 3 miles in width, and running to a point in northern Peoi'ia County and also at the border of the Illinois Valley. Apparently the drift beneath this lowland is mainly till and has considerable depth, one well having gone down 218 feet without entering rock. The well referred to is located oil the farm of John Miller, 4 miles north of Dunlap. The well driller reports that the upper 69 feet was a soft till, mainly of blue color, and probably to be referred to the Shelbyville drift sheet. The remainder was a hard, brownish-gray till, apparently Illinoian. 214 THE ILLINOIS GLACIAL LOBE. Passing- to the east side of the IlUnois, we find the Shelbyville and Bloomington moraines closely associated at the east bluff of the inver, but becoming separated within a few miles southeast to a distance of 10 or 12 miles. An interval of this width separates them from the Mackinaw River southeastward to Kickapoo Creek, near the meridian of Bloomington. The Shelbyville moraine there turns south and the Bloomington moraine turns east, thus leaving a wider interval between the two morainic systems. In the remaining 75 miles from the meridian of Bloomington eastward to the Indiana line the interval between these morainic systems is 40 to 60 miles. This interval, however, as stated above, is not entirely occupied by a plain, but is crossed by several diift ridges, which form the Champaign morainic system and the Cerro Grordo moraine, and these ridges are found mainly east of the Sangamon River. A wide tract west of that stream has a generally plane surface, with only occasional swells, and these but 10 to 30 feet or less in height. This tract included between the Shelbyville moraine on the west, the Bloomington moraine on the north, and the Sangamon River Valley on the east, is underlain by a very thick deposit of drift. Records of several wells which penetrate more than 200 feet were obtained, and it is probable that the average thickness of drift exceeds 200 feet throughout the entire ti-act. The following represent the deepest wells of which records were obtained. At the village of Morton the waterworks well terminates in sand at a depth of 230 feet, and three other wells within 2 miles northwest have about the same depth, and none reach the rock. The engineer at the waterworks states that for about 100 feet the di'ift is soft and easily penetrated, and is mainly of blue color. This, presumably, is the dejith of the Shelbyville drift sheet. The next 100 feet is mostly a hard, gray till, though a bed of sand 20 feet in depth is included. The lower 30 feet is white sand. At Hopedale, 12 miles south of Morton, near the inner border of the Shelbyville moraine, a well made by the railway compan}^ reached a depth of 195 feet. It was mainly till, except the lower 35 feet, which was a fine sand. A bed of black muck was passed through between till sheets, but the precise depth at which it occurred could not be ascertained. In southwestern McLean County a few wells have reached a depth of 200 feet without entering rock, but the majorit}' of tubular wells are 75 feet or less in depth. The Shelbyville drift sheet apparentl}^ has at least this THE SHELBTVILLB MOEAINIG SYSTEM. 215 depth (75 feet), for the wells are entirely tlirough soft till to the water- bearing gravel near the bottom. In the vicinity of Heyworth inflammable gas is found in sand at depths ranging from 155 to 214 feet. The strongest well is located on the farm of J. C AVakefield, three-fourths of a mile southeast of the village, and has the following section, reported by the driller, Mr. Gault: Section of WakefieWs gas well near Heywortli, Illinois. Feet. Till (Shelbyville sheet) 33 Gravel aucl sand (probably Shelbyville) 69 Hard clay ivitli no pebbles or grit 36 Sand 15 Hard blue clay 35 Hard clay Tvitb no grit 11 Black muck 2 Hard gray clay without grit 13 Sand and gravel with gas. Total depth 214 When the gas was struck, sand and gravel were blown out of the mouth of the well, and the well now has a pressure of 22 pounds to the square inch fromi a 2-inch pipe, and supplied fuel for 200 stoves during the winter of 1896-97. At Wapella, a village 6 miles south of Heyworth, the deep tubular wells penetrate about 80 feet of soft blue till referable to the Shelbyville di-ift sheet. Beneath the blue till is a bed of black muck, probably Peorian, with a green clay, apparently a swamp subsoil, underlying it. This is perhaps an lowan silt. Beneath the green clay is a hard bowlder clay, referred to the lUiuoian. Many of the wells are obtained at the base of the Shelbyville sheet at 65 to 80 feet. Those which reach a greater depth obtain their supply from sand associated with the older till, and the sand not infrequently yields a considerable amount of gas. At Leroy, in southern McLean County, the waterworks supply is from a well 110 feet deep, which obtains its water from sand below the' till of the Shelbyville sheet. Wells are occasionally sunk in that ^dcinity to a depth of nearly 200 feet and penetrate a large amount of sand in the lower portion. At Farmer City the waterworks supply is from a well 176 feet in depth which does not reach the rock. It is mainly tlu-ough till, but there are 216 THE ILLINOIS GLACIAL LOBE. several beds of sand and gravel associated with it. A prospect boring for coal made at this city penetrated 189 feet of drift, as follows: Section of boring for coal at Farmer City, Illinois, Teet. Blacksoil 2 Yellow till... 9 Blue till 36 Sand and water 2 Blue till ; 21 Saud and gravel 40 Blue clay 6 Sand and gravel 8 Sandy blue clay 40 Sand and gravel 23 Blue clay 2 Total drift - 189 Several interesting well sections and bluff exposures are found along the west side of the Sangamon River below Mahomet. About 1^ miles southwest of this -sdllage, in sec. 16, T. 20, R. 7 E., the river exposes in its northwest bluff a bed of peat under the Shelbyville till sheet. The expo- sure is several rods in length and the section is as follows: Exposure in hluf of Sangamon River near Mahomet, Illinois. Feet. Yellow till with gravelly places near base, where sjirings issue 10-12 Gray till with yellowish tiuge 20 Peat, earthy except 3 to 6 inches at top 2 Gray earthy subsoil, exposed 2-3 Total, to river bed 36 It is probable that the Shelbyville sheet is reduced at this place to a thickness of only 30 to 32 feet, as the altitude near tlie river is slig-htly lower than the general level of the border jjlains. Wells between this exposure and Mahomet pass through a black muck or peat at about the same level as that exposed along the river. One on the farm of James Lester strikes it at 36 feet, and one at the residence of D. McAi-thur at 42 feet. Mr. McArthur'swell was continued to a depth of 100 feet and ^^ene- trated a harder till below the black muck than that which overlies it. There are places between this exposure and Mahomet where the entii'e bluff is composed of gravel. It is principally on the farm of Mr. Lester, and lie has tested its extent by means of borings and found that it underlies only 60 acres. Around the gravel on all sides except at the southeast, where it fronts the river, there is till. Its dejith is found to reach 50 or 60 feet in THE SHELBYVILLE MORAINIC SYSTEM. 217 places. Its surface lias about the same altitude as the bordering till plain, 35 feet above the Sangamon River. At Dalton City, located about 12 miles southeast of Decatur, the bot- tom of the Shelbyville drift sheet is found at 65 feet, and wells have been sunk to a depth of 150 feet without reaching rock. The majority of wells are about 70 feet. It is not uncommon to find beds of black muck below the Shelbyville drift in the ^acinity of this village. At Bethany, 5 miles southeast of Dalton City, the Shelbyville sheet is apparently only 40 feet in depth. At this depth a greenish clay, associated in places with a black mucky soil, is usually entered. This clay is but a few feet in depth, and is probably an lowan silt. It is underlain by a hard gray till, called hardpan, which seems to be lUinoian. The tubular wells in that vicinity range in depth from 70 to 140 feet without striking rock. At Sullivan the drift, as shown by records published in the Geology of Illinois, has a depth of about 200 feet. The public water supply is from wells 100 to 126 feet in depth. The mayor reports that the upper 50 feet is a soft blue till, beneath which considerable sand is penetrated. This is underlain by a hard till which is penetrated 40 feet or more before the water- bearing gravel is reached. In northern Coles County, between Humboldt and Fair Grange, wells are 60 to 120 feet in depth without reaching- rock. In some wells a hard gray till is struck at about 50 or 60 feet. The overlying till is soft and probably is referable to the Shelbyville sheet. At Oakland, in northeast- ern Coles County, rock is entered at about 50 feet. At Kansas, in western Edgar County, rock is entered at 80 feet or less. lu a few cases wells have struck a black soil at about 30 feet, which is probably just below the Shelbyville drift sheet. A well midway between Kansas and Isabel entered rock at only 40 feet, but others in that vicinity 50 feet or more in depth do not strike rock. In the eastern part of Edgar County, on Clay's Prairie, rock is occasionally struck at only 20 or 25 feet, and is extensively exposed along Bruillett's Creek, in eastern Edgar County, Illinois, and southern Vermilion County, Indiana. The general thickness of the di-ift in that region can scarcely exceed 40 feet. The Indiana district, immediately north from the Shelbyville moraine, has generally a comparatively thin sheet of drift on the uplands, rock often being struck at 50 feet or less, but in the preglacial valle}"s the di'ift may 218 THE ILLINOIS GLACIAL LOBE. exceed 150 feet in thickness. As there are several moraines crossing this district the discussion of its features is taken up in connection with them on later pages CERRO GORDO MORAINE. DISTRIBUTION. The CeiTo Gordo moraine emerges from beneath the Champaign moraine opposite the village of Mahomet, in Champaign County, and fol- lows the east border of the Sangamon River Valley, at a distance of 1 to 3 miles from the stream, from Mahomet southward to CeiTO Grordo, a village 10 miles east of Decatiu-. It there swings away from the river, and is dis- tinctly traceable only to Laplace, 6 miles south of Cerro Gordo, there being for a few miles no definite continuation. A distinct ridge, however, appears near Humboldt, in northern Coles County, which is supposed to be its continuation. This ridge is traceable in a general eastward course, but with slight windings, tlu'ough southeastern Douglas and central Edgar counties. The interval between the Cerro Gordo and Shelbyville moraines varies greatly in width. Near the city of Paris they are closely associated ; at Humboldt they are separated by a space of 10 or 12 miles, and a similar interval is found opposite Cerro Gordo. From CeiTO Gordo northward the ridges pursue divergent courses, so that opposite Mahomet they are separated by a space of 25 or 30 miles. TOPOaBAPHIC EXPRESSION. The portion of the moraine between Mahomet and Laplace consists of an irregular aggregation of drift swells and short ridges, occupying a belt about 2 miles in average width. The knolls are so closely aggregated that very little plane surface is found among them. The usual height is 10 to 20 feet, but a few are 30 feet or more above bordering low ground. The belt is sharply in contrast with the level tract to the east, and has on the whole a stronger expression than the Shelbyville moraine. The portion leading eastward from Humboldt presents more variation in topography than the portion just mentioned. In northern Coles and southeastern Douglas counties, and for several miles in western Edgar County, it consists of a smooth till ridge one-half mile to a mile in width, with a relief of 20 to 30 feet. In places it is but 60 to 80 rods wide, and THE CEREO GORDO MORAINE. 219 stands only 10 to 15 feet above the border plain. The ridge is nearly continuous except at the Embarras River, which cuts through it o^jposite Dora Station. In Edgar County the belt has, on the whole, a stronger expression, though there is not so continuous a ridge as in Douglas and Coles counties. There are several small ridges, one-fourth mile or less in width and 10 to 20 feet in height, which form a disjointed chain leading southeastward from Brocton to Paris. Associated with these there are knolls of considerable prominence. A cluster in sees. 15, 16, and 17, T. 14, R. 12 W., known as the Blue Mounds, rise 50 or 60 feet above the border plains. An isolated knoll in sec. 32, T. 15, R. 13 W., is about 50 feet in height and occupies perhaps 20 acres. North and northwest from this knoll, in sees. 29 and 30, several knolls rise abruptly to a height of 20 or 30 feet, and one to a height of 40 feet. In the northeast part of Paris there is a ridge leading from Sugar Creek southwestward about 1 J miles, which is 30 to 60 feet in height and has a billowy surface. Its width is 40 to 60 rods. Probably this ridge belongs in the belt under discussion, though it is slightly out of line with the belt and is separated from it by a plane tract about 2 miles in width. Toward the northeast there are occasional knolls as far as the State line, but no definite ridge or chain of knolls appears. The well-defined belt terminates at the Blue Mounds. STKUOTUKE OF THE DEIFT. Some of the sharpe:- knolls of the moraine contain gravel and sand, especially along the border of the Sangamon River and in Edgar County. There is, as a rule, considerable till associated with the gravel and sand, and the knolls are usually underlain by a sheet of till. The gentle swells and the smooth ridges are composed more larg-ely of till than those of sharper contour. The majority of wells along this belt obtain their sujjply at a level little, if any, below the base of the knolls and ridges and within the limits of the early Wisconsin drift sheets. A few pass into the older drift. Very rarely a well reaches the rock. The drift, as in the tract outside the moraine, is very thick in Illinois except in the vicinity of the State line, but is thin in Indiana. The following are the deepest wells of which records were obtained : On H. H. Hollis's farm, in sec. 30, T. 20, R. 7 E., a well is 215 feet in 220 THE illiin'OIS glacial lobe. depth, and on B. F. Hollis's farm, in sec. 31, two wells are 190 feet in depth, without reaching rock. The drift is largely a blue till and but a small part is thought to belong to the early Wisconsin. It is described to be mainly hard till below a depth of 40 feet. F. Gr. Seymoin- has a well in sec. 6, T. 19, R. 7 E., 215 feet in depth, which is similar to the wells on the Hollis farms. At Monticello the city water supply is from two wells 212 and 303 feet in depth, neither of wliich enters rock. The early Wisconsin drift here is apparently but 20 feet thick, the wells being on low ground near the San- gamon River. The following is the record of the deeper well as published in the Piatt Independent soon after the completion of the well in 1891: Section of a waterworks well at Monticello, Illinois. Foet. Black lo?m 3 Yellow clay 10 Blue clay (gravelly) 7 Brown peaty loam (Peorianf) 7 Sand and gravel 2 Blue clay 11 Sand, gravel, and water 5 Silt 1-2 Sand' gravel, and water 55 Hard blue clay (pebbly "bardpan ") 49^ Quicksand - 75^ Sand and gravel 64 Coarse gravel 2 Total 303 In the A-eins of water above the "hardpan" the water is less suitable for culinary and laundry purposes than in those below, because of greater hardness. Both wells are, therefore, sunk to a coarse gravel in the lower water bed. At Bement a well in the business 23art of town struck rock at 222 feet and is 225 feet in depth. Wells at the waterworks, the railway station, and the mill obtain a good supply of water at 140 to 150 feet, after penetrating a large amount of blue till. It is not certain that the Wisconsin di-ift has so great a depth as 150 feet at this point, the records of wells being imper- fect. At the cemetery, 2 miles north of Bement, near the crest of the Cerro Gordo moraine, a well 221 feet in depth is mainly through blue till and does not reach rock. At Cerro Gordo there is a nearly solid bed of blue till to a depth of 150 feet, and strong wells are seldom obtained at less depth. That the THE CEREO GORDO MOEAINE. 221 Wisconsin diift lias a depth of 150 feet at tins point is supported by the fact that the moraine there reaches an altitude nearly 150 feet above the level of the buried soil along the Sangamon Valley at Monticello and near Mahomet. Along the ridge from Humboldt eastward into Douglas County wells apparently reach the base of the Wisconsin drift at 65 to 75 feet, and farther east at 50 feet or less. The sharp ridge situated in the northeast part of Paris has been opened extensively for gravel. There is at the surface a brownish yellow till 5 to 15 feet thick, and beneath this are beds of calcareous sand several feet in depth. Beneatli the sand there is a sandy gravel. Both the sand and the gravel show considerable cross-bedded structure. The beds are also arched, and appear to have been crumpled somewhat as if by a disturb- ance by the ice sheet. In order to ascertain the proportion of the various kinds of rock in this gravel, a small space was marked off in the gravel pit and the pebbles therein were classified, with the following result : Classification of pehhles in a gravel pit at Paris, Illinois. Granite g Otlier crystalline rocks 8 Quartz 3 Chert of light color 13 BroTvn chert 1 Carboniferous sandstone (local) H Gray limestone (probably local) ' 45 Magnesian limestone 4g Total 1^ A few of the gray limestone pebbles are striated. These pebbles show less rounding by water action than other classes. It is probable that some of them are from the Carboniferous limestone exposed near Baldwinsville, north of Paris. CHARACTER OF THE OUTWASH. The character of the outwash from the Cerro Grordo moraine has received very httle attention. It has been noted, however, that the valleys leading away from the moraine, with the exception of the Sangamon, are small and are usually cut in till. There can not, therefore, be very heavy sand or gravel outwash. Along the Sangamon Eiver for a few miles below Mahomet this morainic belt is bordered on the west by a gravelly plain, whose origin and 222 THE ILLINOIS GLACIAL LOBE. relationships are not fully determined. It may be due largely to the cutting down of gravelly portions of the Shelbyville sheet, such as that near Mahomet just noted. It stands about 20 feet above the Sangamon River, or about halfway from the level of the river up to the level of the till plain on the west. In places the morainic knolls east of the river extend down to the level of this gravelly plain, and seem to be merged with it so intimately that there is a strong suggestion of similarity in age. However, it is not fully established that even in such places the gravel is an outwash from the moraine. As shown below, there is a light gravelly outwash near Mahomet from the Champaign moraine over the till plain that borders it on the south. It is possible that the gravel plain along the valley was built up in part at that time, though the lightness of the deposit at Mahomet scarcely warrants the reference of a large part of the filling to this source. INNER BORDER TRACT. Between the Cerro Grordo moraine and the outer ridge of the Champaign morainic system there is a plain whose width nowhere exceeds 26 miles and usually is about 12 or 15 miles. This plain has a very level surface, there being few swells or knolls and but little variation in altitude. It is under- lain bv thick deposits of drift, except for a few miles near the State line. Wells indicate that it may average nearly 200 feet, of which probably more than one-half is older than the Shelbyville sheet. Since the majority of wells obtain water without reaching the base of the Shelbyville sheet, few data concerning the older di'ift are available from this region, but inferences may be drawn to some extent from neighboring districts on either side, where the data concerning thickness of the drift are more full. Wells in the ^-icinitv of Areola are reported to have ^^assed from the s©ft till of the Shelbyville sheet into a harder till, presumably of the older drift, at a depth of only 45 or 50 feet. In the vicinit}- of Tuscola the wells usually pass from the soft till of the Shelbyville sheet to a harder till, termed hardpan, at a depth of 35 to 40 feet. A prospect boring for coal at Tuscola penetrated 186 feet of drift. It is probable that the thick- ness of the Wisconsin drift is somewhat greater on the portion of the plain to the west of these towns, as shown by records outside the Cerro Grordo moraine already given. The thickness to the east of these villages is prob- ' ably less rather than greater than in their vicinity, there being a general decrease in thickness in that direction. THE EARLY WISOONSIN DRIFT SHEETS. 223 SECTION II. CHAMPAIGN MOEAINIC SYSTEM. Under this head is discussed a group of closely associated ridges which interlock to some extent, but usually consist of two or three distinct mem- bers. The system receives its name from the city of Champaign, Illinois, the site of the State University. The ridges, which are more or less dis- tinct east from this city, become united in a single ridge from this city westward. The discussion begins at the westernmost point at which the system has been recognized, and proceeds eastward to the point of disap- pearance beneath a morainic system of late Wisconsin age. In the com- plex portion separate names have been applied to the several members, viz, Outer or West Ridge, Middle Ridge, and Inner Ridge DISTRIBUTION. The westernmost prominent development of the Champaign morainic system is found in " Blue Ridge," which sets in near the village of Blue Ridge, in northern Piatt County, and leads southeastward into Champaign County. There is, howevqr, a narrow belt, with rather more undulation than is common on till plains, which leads westward from near the north end of Blue Ridge past Leroy to the Bloomington moraine at Downs, and which is doubtfully referred to the Champaign morainic system. This undulatory belt stands 20 to 30 feet or more above the general level of the plain on the south, but the rise is so gradual that the relief is scarcely perceptible. The portion known as Blue Ridge comes to the Sangamon River just above Mahomet. With a gap scarcely one-half mile wide the moraine reappears on the east bluff, and leads southeastward to Champaign, crossing the Cleveland, Cincimiati, Chicago and St. Louis Railway west of the city. The width from Blue Ridge to Champaign averages about 2 miles. A short distance west of Champaign the Outer or West Ridge sepa- rates from the main belt and passes southward through Savoy and Tolono to West Ridge village, in Douglas County, near which it swings rapidly eastward and joins the middle member of the series in southwestern Ver- milion County. This ridge has an average breadth of scarcely one-half mile in its north-south portion, but in the west-east portion it increases to a width of nearly 2 miles and becomes the principal i-idge of the series. 224 THE ILLINOIS GLACIAL LOBE. From Champaign a ridge nearly as bulky as the combined belt leads southeastward through Philo. A short distance southeast of this village it separates into two quite distinct ridges. One continues the southeast course past Broadland and joins the outer ridge in southwestern Vermilion County. The inner ridge passes eastward into Vermilion County along a line nearly parallel with, and about 2 miles south of, the Wabash Railway until it reaches the meridian of Fainuount, where it turns southeastward. It comes to Little Vermilion River east of Georgetown and follows the north side of that stream to the Wabash Valley. East of the Wabash its course is north- eastward to Veedersburg, and thence eastward into western Montgomery County, where it is overridden by a late Wisconsin moraine and its further course lost to \aew. This ridge throughout its entire length is naiTow and low, seldom exceeding one-half mile in width, and rising but a few feet above border plains. It is also scarcely so continuous as the other mem- bers of the series. From Veedersburg another weak drift ridge leads northward past Rob Roy to the Wabash Valle}^ near Attica, beyond which it can not be traced, because of concealment beneath later moraines. Returning to southwestern Vermilion County, where the Middle and Outer ridg'es become united, and tracing theii" further course, one finds a ridge about 2 miles wide and 60 to 100 feet high passing eastward near the line of Vermilion and Edgar counties into Indiana. In places it has a double crest, but in other places it is a thoroughly combined belt. For a few miles on the west side of the Wabash River it is not well defined, but it is easily located on the east bluff just below the mouth of Sugar Creek. Its course for about 8 miles is south of east. It there curves, near the village of Bloomingdale, and takes a nearly northeast course, crossing Sugar Creek at a narrow gorge known as " The Shades of Death" near the line of Parke and Montgomery counties. In western Montgomery County near the village of Alamo, which stands on its crest, the course is again changed toward the north, and it trends nearly due north to where it is oveiTidden by a moi'aine of the late Wisconsin series, near Wesley, Indiana. The course of the members of the Chamjiaign system is such tliat the Inner Ridge is separated from the combined ]\Iiddle and Outer belt by a space 15 to 20 miles in width in the district immediately east of the Wabash, while west from that valley the space is 10 miles or less. The THE CHAMPAIGN MORAINIO SYSTEM. 225 Outer Ridge at its widest separation from the Middle one is distant but 8 or 9 miles. It is separated from the Middle Ridge for only about 30 miles of the 100 or more miles in which they are exposed to view. The Inner Ridge is distinct from the others for a much longer distance, being combined with them for only about 30 miles of the 100 which the belt occupies. It will be observed that the moraines are looped across the Wabash Basin after the fashion of the looping of the late Wisconsin moraines about the basins and large valleys, as brought to notice by Chamberlin in the Third Annual Report of this Survey. The axis of the Wabash Basin is depressed only 150 to 200 feet (aside from the immediate valley of the river) below the borders of its watershed where crossed by this morainic system. This slight amount of depression seems scarcely adequate to be the sole cause for the protrusion of the ice sheet into the valley, though it no doubt had some influence. EELIBF. The relief of the combined belt between Blue Ridge and Champaign reaches about 90 feet above the outer-border plain at several points, though it usually is about 60 to 75 feet. The outer-border plain declines from 750 feet at Blue Ridge to about 710 or 720 feet east of the Sangamon. The crest of the moraine reaches 820 feet in northern Piatt County, and 800 to 810 feet near Rising in Champaign County, but averages only about 775 feet above tide. The inner-border plain lying north of this portion of the, moraine stands about 730 feet above tide. The outer ridge has a measured relief of 45 feet on the outer border and 40 feet on the inner border at the crossing of the Wabash Railway at Tolono, but at the crossing of the Chicago and Eastern Illinois at West Ridge it scarcely exceeds 35 feet on either border. Farther east, near its junction with the Middle Ridge, the relief increases to 70 feet, and one point near Palermo, used by the United States Lake Sxirvey as a site for a geodetic station, stands 90 feet above the general level of the outer border plain. The Middle Ridge has a relief of 25 or 30 feet on its outer border tlu'oughout the interval in which it is distinct from the Outer Ridge. On its inner border the relief is about 20 feet. At Philo, where the Inner and Middle ridges are combined, the outer-border relief, as shown by the MON xxxviii 15 226 THE ILLINOIS GLACIAL LOBE. Wabash Railway sui-ve}', is 30 or 35 feet, while the inner-border relief is about 50 feet. The relief of the Inner Ridge throughout its entire course in Illinois and Indiana is but 15 to 20 feet, except where knolls rise above the general level of the crest. In such cases a relief of 40 or 50 feet may be foinid. The combined Middle and Outer ridge has a general relief in eastern Illinois of about 40 feet above the outer-border plain and about the same relief above the inner border. Where there is a double crest, the sag between the crests is 15 to 25 feet in depth. In the Indiana portion the relief seldom reaches 40 feet, and the aver- age is probablj 30 feet above the plains on the outer and inner border. It appears from the data just given that the outer and inner border reliefs in this morainic system are not markedly different. There is not such a filling on the inner border and transition from the moraine into the plain as in the Shelbyville or Cerro Gordo moraines. As seen in profile, the ridges of the Champaign system rise with nearly as rapid slope on the inner as on the outer border, a feature which distinguishes them from nearly all of the moraines of the Wisconsin series, it being' the h?bit of the Wisconsin moraines to present a long inner slope and a somewhat abrupt outer slope. KANGE IN ALTITUDE. As indicated above, the moraine, near the western end, attains an alti- tude of 820 feet above tide, while the border plains are about 750 feet. The altitude of the plains decreases to about 700 feet in southern Champaign Coimtv and to 660 feet in the vicinity of the Embarras River, in northern Douglas County. From this point eastward to the borders of the Wabash the plains stand 650 to 675 feet along the border of the combined Middle and Outer ridge. The altitude is less uniform along the line of the Inner Ridge, there being a range of about 75 feet in the Illinois portion. The liighest part of the plain near Sandusky is fully 720 feet above tide, while in the western part of the county it scarcely reaches 675 feet, and in the eastern it falls to about 650 feet. On the borders of the Wabash in western Indiana the altitude of the upland plain declines to about 600 feet. There is a gradual rise from the valley eastward to 775 or 800 feet in western Montgomery County, where the moraines of this system pass beneath a moraine of the late Wisconsin series. THE CHAMPAIGN MORAINIC SYSTEM. 227 SURFACE CONTOURS. On the whole the ridges of this system are of a type which may best be designated the smooth-ridge type, the surface undulations being very gentle, while the crest is usually well defined. A detailed examination, however, brings to light considerable variation in the features. The portion west of the Sangamon River, known as Blue Ridge, has a well-defined crest, along which undulations of 10 to 20 feet occur. On its slojDes also there are gentle swells 5 to 15 feet in height. In the vicinity of the Sangamon River a few knolls of greater prominence appear, though the highest scarcely rise more than 40 feet above bordering low ground. Between the Sangamon River and Champaign the moraine presents a well- defined crest and undulatory slopes. The undulations commonly fall below 20 feet, both along the crest and on the slopes. The outer face is more abrupt than the inner, there being places where a rise of 50 feet is made within a mile from the border of the plain outside the moraine. The Outer Ridge from the city of Champaign around to northeastern Douglas County has a very smooth surface, in which undulations seldom exceed 10 feet. The relief of 20 to 40 feet, however, makes the ridge a noticeable feature. In passing eastward through northern Douglas County the ridge becomes much larger, but maintains a nearly smooth surface. A short distance west of its jiinction with the Middle Ridge it jjresents a double crest, but each ridge is very smooth. The belt leading southeast from the city of Champaign presents swells 15 feet or more in height, but the crest is ill defined between the city of Champaign and sec. 33, Ui-bana Township. From this section southeast- ward, through Philo Township, and thence eastward to sec. 4, Raymond Township, the crest is well developed. It has oscillations of from 10 to 25 feet, and the slopes are characterized by knolls of similar elevation. In the vicinity of Lynn Grrove geodetic station knolls and sharp winding ridges 30 or 40 feet in height occur, and the moraine maintains this strength of expression for about 3 miles east from the geodetic station. It there loses , strength, and in northeastern Raymond and South townships, ChamjDaign County, and in Sidell Township, Vermilion County, it consists of a smooth ridge scarcely 20 feet higher than the plain south of it. North of this 228 THE ILLINOIS GLACIAL LOBE. ridge there are scattering knolls surrounded Ijy -s-ery level tracts. One knoll near the line of sees. 1 and 2, Raymond Township, co^"ers not less than 10 acres and has a height of probably 30 feet. Other knolls 10 to 25 feet in height were observed. The Middle Ridge does not connect closely with the Outer Ridge in southeastern Champaign and southwestern Ver- milion counties, but is separated from it by a sag or depressed tract a half mile or less in width. This depression connects on the east with the Little Vermilion River and on the west with the Nile, a tributary of Emban-as River. For about 5 miles eastward from the Palermo geodetic station a single broad ridge, IJ to 2 miles wide, constitutes the equivalent or continuation of the two ridges found farther west. It does not long continue the sole representative, however, for another ridge sets in just north of the head- waters of Bruillett's Creek, in sec. 4, T. 16, R. 12 W. From this section eastward nearly to the State line there is a double ridge, tlie members of which are nowhere separated more than one-half mile. Mortimer stands on the outer and Ridg-e Farm ^nllage on the inner of these ridges. A few basins occur along the ridges in southeastern Vermilion County, the deepest of which are depressed 8 or 10 feet below bordering land and are occupied by peat bogs. The ridges have gentle undulations of 10 to 20 feet, both along the crest and on the slopes. The Outer Ridge has interruptions or gaps which afford a passage for waters which fall be'tween the two ridges south- ward to the outer-border plain. The gap through which Bruillett's Creek passes is nearly 75 feet in depth and less than one-half mile in width. Sev- eral other gaps of less depth occur, all of which are quite narrow. They appear to have been deepened considerably b}' the streams which pass through them. The two ridges become coalesced at Pilot Grove, a promi- nent point in sec. 33, T. 17, R. 11 W. From this grove eastward to the State line, knolls and ridges rise from the crest and slojDe somewhat al>ruptly to heights of 15 or 20 feet, and give the moraine a sharper expression than is usually dis])laYed. From the State line eastward to the Wabash River the l)idk as well as the expression, decreases, the crest becomes poorh" defined, and the undulations are scarcely 10 feet in height. For a few miles east of the Wabasli River the moraine is represented by knolls only, there being no well-defined ridge or crest line. The most ])rominent knolls observed are in sec. 17, Reserve Town.shi]), Parke County. THE CHAMPAIGN MOKAINIC SYSTEM. 229 They are somewhat elongated in a NW.-SE. chrection, and rise abruptly to a height of 20 or 30 feet. Farther east, in the vicinity of Bloomingdale, the knolls are in some cases 30 feet or more in height. In sees. 24 and 19, 25 and 30, T. 16, Rs. 7 and 8 W., the moraine consists of a ridge 80 rods to a mile or more in width, on whose slopes and crest knolls 10 to 25 feet in height are numerous. Outside the main ridge there is, in sec. 29, a chain of knolls 15 to 20 feet high, rising abruptly above the bordering plane tract. In eastern Parke County the moraine for a distance of about 10 miles constitutes the water parting between Little Raccoon and Sugar creeks, and there is scarcely a mile of this portion on which knolls 15 to 25 feet high do not occur, while in some sections they reach heights of 30 or 40 feet These knolls stand upon a basement ridge whose relief, independent of the knolls, is 30 or 40 feet. In this part of the moraine the knolls are arrai:iged in chains trending parallel with the crest. In southwestern Mont- gomery County, on the south side of Sugar Creek, there are numerous sharp knolls in the moraine, but not a distinct ridging or well-defined crest. North of Sugar Creek the moraine assumes a ridged form near the south line of sec. 34, T. 18, R. 6 W., from which point the ridge leads NNE. through Alamo. Its general height is about 30 feet above the plain west of it, and still more above the bluff of Sugar Creek Valley on the east. Near Alamo, in sees. 23 and 26, several basins occur, the deepest of which are 15 or 20 feet below their bordering rims. The basins iisually have outlets through narrow breaks in the rim. West of the main belt for several miiles the surface is very flat, but east of it there are ridges and knolls extending to the valley of Sugar Creek. The knolls are nearly as prominent as those in the main belt, but are less closely aggregated. They are separated by nearly plane tracts. The northeast fourth of Ripley Township, comprising a tract 3 or 4 miles wide, is sharply tmdulatory, with many knolls and ridg-es 20 to 40 feet high. The moraine here is over- ridden by a late Wisconsin moraine. The latter trends NNW.-SSE., intersecting the Champaign moraine at an angle of about 45 degrees. The Inner Ridge of the Champaign morainic system is well defined from its point of separation from the Middle Ridge, near Philo, Illinois, eastwai'd to the Fairmount geodetic station. It is about one-half mile in width and 20 feet in height, and presents a gently undulating surface. South and east from the geodetic station there is a series of knolls and 230 THE ILLINOIS GLACIAL LOBE. short, rather sharp, ridges. The most promiueut ridge traverses sees. 25, 26, and 36, T. 18, R. 13 W., and its highest points stand fully 50 feet above the bordering plain, yet its width, including slopes, is scarcely one- half mile. A lower ridge passes north-south through sees. 16 and 21. In sees. 9 and 10 also there is a low ridge which ti-ends WNW.-ESE., and stands perhaps 20 feet above the bordering plain. Blue Mound, a shai-p knoll in sec. 11, stands 55 feet, by aneroid, above the border plain and covers about 30 acres. In sees. 10 and 15, T. 18, R. 12 "VV., a well-defined undu- latory ridge occurs which carries shallow basins on its crest and slopes. There are several knolls 10 or 15 feet high in sees. 7 and 18 of this town- ship, which should probably be referred to this moraiiiic belt. From Blue Mound, in sec. 11, T. 18, R. 13 W., to sec. 27, T. 18, R. 11 W., a distance of 10 miles, only occasional low ridges and knolls are to be seen, the highest of which i-ise scarcely more than 15 feet above the bordering plain. But from sec. 27 southeastward to the Wabash River bluff near Eugene, Indiana, a distance of 7 to 8 miles, there is a well-defined ridge, about a half mile in width, whose highest points rise 40 feet or more above the bordering plain, while its lower points seldom fall below 20 feet. It carries winding ridges and sharp knolls on its surface, among which shallow basins are inclosed. East from the Wabash River this moraine has, as a nile, a gentle swell-and-sag topography, with undulations of 10 feet or less and a relief of scarcely 20 feet. In the vicinity of Rynear, however, in sees. 2 and 3, T. 19, R. 7 W., there is a chain of knolls standing 20 to 40 feet higher than the plain on the north, and occupying a belt about a half mile in width. The Cleveland, Cincinnati, Chicago and St. Louis Railway passes over a spur from this ridge just east of Rynear, while west of the village it passes through a gap in the ridge. In sec. 9 the ridge takes a NE. to SW. trend and is dis- tinctly traceable to the southwest part of the section. The remainder of this belt consists of knolls more or less closely aggregated but seldom exceeding ? feet in height. The weak l>elt leading northward from Veedersburg to Rob Roy has no prominent knolls except in the northern portion. The slight undula- tions which it presents, however, are in decided contrast to the very flat surface of the plain on the west. Although the moraine has but feeble expression its relief is sufficient to cause the sontliwavd deflection of Coal THE CHAMPAIGN MOEAINIC SYSTEM. 231 Creek. The slope of the country is such that the creek would have con- tinued directly westward to the Wabash and reached that river in about 6 miles from the point where it encounters the drift ridge, but the deflection occasioned by the drift ridge makes it necessary for it to flow not less than 25 miles before reaching the Wabash. At the northern end of the rido-e. near Kob Roy, knolls 20 to 30 feet high occur, and points in sec. 25, T. 21, R. 8 W., stand 50 or 60 feet above the bordering plain. To give added morainic expression these prominent points are thickly strewn with bowlders. THICKNESS AND STRUCTUEE OF THE DRIFT. The thickness of drift in this morainic system is to be measui-ed by the relief of its ridges rather than by the distance to rock, for beneath the level of the base of the ridges older sheets of drift occur. The relief, as shown above, nowhere reaches 100 feet and seldom exceeds 50 feet. The distance to rock, on the other hand, rarely falls below 50 feet along the line of the ridges, and in places is known to be 300 feet. In the Indiana portion and in eastern Illinois, for some 20 miles west of the State line, rock is usually entered at 100 feet or less, and there are numerous rock exposures along the principal streams. Farther west the rock surface lies lower, and the few borings which reach the rock indicate that the average thickness of the drift in Champaign, Piatt, and McLean counties is not less than 200 feet, while the maximum thickness is fully 300 feet. These morainic ridges are composed in" the main of till. Gravel and sand beds are occasionally foimd in the knolls and near the level of the base of the ridges, but even in these situations they are of comparatively limited extent. Along this morainic system in Indiana there is sufficient gravel in the knolls to supply material for improving the roads in their vicinity, but in Illinois road material is generally difficult to obtain. Grravelly knolls were observed east of Ridge Farm village and on the inner slope of the moraine near Champaign and Urbana. Along the shai-ply ridged portion of the inner ridge in the vicinity of the State line, and also in the sharp knolls near Fairmount, there is considerable gravel associated with the till. It is possible that many knolls contain gi-avel wliich has not yet been discovered. On the whole, water-bearing beds are more extensive in the Indiana portion of these morainic ridges than in the Illinois portion. In the latter district wells are often sunk to a level below the base of these 232 THE ILLINOIS GLACIAL LOBE. di'ift ridges before water can be obtained, while in Indiana, water-bearing beds are usually found before reaching the base of the ridges. This morainic system is characterized by a limited number of surface bowlders, and a moderate number are incorporated with the till. The majority of the surface l)owlders are crystalline rocks of Canadian deriva- tion. They are usually subangular and seldom show striated faces. As in the di'ift sheets of this region generally, the bowlders incorporated in the till appear to be much more frequently glaciated than those on the surface. There is also apparently a larger proportion of limestone rocks of local or semilocal derivation embedded in the till than are found on the surface.^ Several large blocks of limestone, however, were found on the surface in Champaign County, Illinois. At George Stewart's, a few miles southeast of Philo, on a prominent portion of the ridge in sec. 4, T. 17, R. 10 W., two large limestone blocks were examined by the writei*. They are of gray color and contain Pentamerus shells, apparently of Niagara age. Mr. Stewart has dug to a depth of about 4 feet at the side of one of the rocks without reaching its base, and it has a surface exposure nearly 10 feet square. The other block has been uncovered for a space of about a square rod and extends some distance beneath the ground. The nearest known outcrop of this rock formation toward the north (the direction from which the ice came) is in northern Iroquois County, some 60 miles distant. In Indiana the district traversed by these moraines and the morainic ridges themselves are characterized by few surface bowlders, excejDt in north- western Montgomery and northeastern Fountain counties. They there aliound on the plains as Avell as on the ridges. It seems probable, however, that these bowlders are to be connected with the late Wisconsin ice invasion, though their position is such as to throw them outside a regular border of the ice sheet. The bowlders apparently connect on the north with well- defined bowlder belts of late Wisconsin age which lead northward from the AVabash River near Williamsport. Whether the bowlders on the group of knolls near Rob Roy referred to above were deposited by this later invasion is uncertain. It is also not entirely certain that these knolls are independ- ent (if the later invasion. The surface of the ridges of the Champaign morainic system, as well as the plains between them, is commonly covei'cd with a pebbleless clay I For (lisciiSBion of these features see Cbamliorlin : ,Jour. Geol., Vol. 1, 1803, pp. 47-60. THE CHAMPAIGN MORAINIC SYSTEM. 233 loam 2 to 4 feet in thickness, and this has probably concealed many bowlders which would otherwise have been exposed on the sm-face of the till. The number of bowlders on the surface is less than on the plains between this morainic system and the Cerro Gordo moraine. The sheet of loam is apparently distinct in origin from the sheet of till which underlies it, but no evidence was discovered that it was separated from it by a wide time interval. This silt is distinct from the main loess deposit of western and southern Illinois, since the latter preceded the Shelbysalle moraine in its date of deposition. The origin of surface silts of this class, like that of the great loess deposits, is problematical. A buried soil is frequently found beneath the ridges of this morainic system, but it appears to be at a lower horizon than the base of the drift deposited in connection with these moraines. Its horizon is probably at the junction of the Shelby ville drift sheet with the underlying older di-ift. Professor Rolfe, of the Illinois State University, has collected records of many wells in southern Champaign County, between Urbana and Tolono, in which a buried soil is found at a depth of 60 to 100 feet. These records have not as yet been published by him. When found beneath the plains the depth to the soil is less than when beneath the drift ridges. On the ridge in the vicinity of Tolono it is struck at about 100 feet and it is found at nearly as great depth on the ridge near Urbana, while on intervening plains the depth is but 60 to 75 feet. Instances of buried muck reported from Vermilion County, Indiana, by F. H. Bradley^ occur beneath the gravel of the Wabash terraces. Wells were sunk through about 60 feet of alluvial sand, and then encountered 6 to 10 feet of soft, sticky bluish mud filled with leaves, twigs, and trunks of trees. In Fountain County, Indiana, between the main morainic belt and the Inner Ridge, there is a plain in which a black muck has been struck below the till at depths of 25 to 50 feet. Although the depth is much less than in Champaign County, Illinois, the soil is thought to be at the same horizon, namely, the junction of the Shelbyville drift sheet with the underlying older di-ift. The detailed discussion of well sections which follows beg-ins at the west end of the morainic system in Piatt County and passes eastward, and serves to illusti'ate variations in the structure from point to point. There are, ixnfortunately, but few reliable records obtained. ' Geol. of Indiana, 1869, p. 140. 234 THE ILLINOIS GLACIAL LOBE. A well oa the farm of Mrs. Robert Carson, iu eastern Piatt Couut"S', near tlie south border of the moraine, reached a depth of 200 feet without encountering rock. It appears to have been mainly through a fine sand. On the north border of Blue Ridge Frank Delaney sunk a well to a depth of 280 feet without encountering I'ock. A well was sunk by George Frank- enburgher on the crest of the moraine, 2 miles east of Mahomet, to a depth of about 200 feet without encountering rock. It was almost entu-ely through till. An experimental boring for gas, oil, etc., made at the city of Cham- paign in the winter of 1891-92, is reported by E. M. Bvut, of Champaign, to have the following drift section: Section of horimj at Champaign, Illinois. Feet. Black soil and a pebbleless clay subsoil -. 4 Yellow and gray pebbly clay 44 Quicksand 12 Gravel 7 Gray pebbly clay 35 Quicksand - 71 Water-bearing gravel 6 Hanlpan (exact nature not noted) 5 Quicksand 11 Gravel 7 Hard, pebbly clay 51 Clay containing small pieces of coal 1 Quicksand and gravel 21 Gray clay containing pieces of coal near bottom 9 Quicksand 16 Total drift 300 The following section of an attempted coal shaft sunk by Jolin Faulds at Champaign appears in the Geology of Illinois (Vol. IV., p. 272): Section of coal shaft at Ghamimign, Illinois. Feet. Soil, clay, and ([uicksaud 17 Red and blue clay 73 Peat 2 Quicksand, with tree 7 inches in diameter 9 Soft yellow clay 9 Sand 3 Yellow clay 7 Sand and gravel 59 Total depth 179 The bottom of the drift was not reached in this place. The statement is made that nn earlier boring near l)y, of which a complete record was not THE CHAMPAIGN MORAINIO SYSTEM. 235 accessible, is said to have reached a bkie shale at 168 feet. This sup- posed shale may, however, prove to be hard blue till. A boring made iu Urbana in 1884, about a half mile east of the roundhouse of the Cleveland, Cincinnati, Chicago and St. Louis Railway, has the following section, as reported by Prof C. W. Rolfe: Section of boring at Urbana, Illinois. I'eet. Soil - 1 Yellow clay containing few pebbles .- 12 Blue cla)- containing few pebbles 13 Very stony clay 32 Coarse sand and gravel I't Black soil 2 AVater-bearing yellow sand Ifi Blue clay 1 Quicksand ^i Blue clay - 1 Quicksand .- - 3 Blue bowlder clay 16 Quicksand - 35 Blue bowlder clay li^ Sand and gravel - 17 Quicksand 69 Gravelly sand 9 Total drift 265 The altitude of the well mouths, both in the Champaign and in the Urbana borings, is about 750 feet above tide. Within IJ miles east of the com-t-house in Urbana, at a level but a little lower than the well just recorded, rock is struck within 100 feet of the surface. On a line eastward from that point to the Wabash Valley, in Indiana, the drift seldom exceeds 100 feet in thickness. A well at Thomas Goody's, in Philo, on the crest of the moraine, attained a depth of 171 feet without reaching rock, and penetrated the following drift beds: Section of icell at Philo, Illinois. Feet. Pebbly clay changing from brown to blue 20 Pebbly bhie clay 75 Pebbly blue clay, interbedded with dry sand in thin beds 30-35 Sandy clay called hardpan 4 Fine yellow sand, water bearing 36 Total 171 A well on the moraine 2 miles south of Philo, in process of boring at the time of my visit, penetrated 110 feet of till, mainly of blue color, and 236 THE ILLIN^OIS GLACIAL LOBE. .apparently referable to the Shelbyville aud later sheets. Beneath tliis depth alternating beds of sand and clay of blue color continued 46 feet to the bottom of the well. Several other wells have l^eeu made along the moraine in this count}* whose depths exceed 100 feet. As a rule they pass through a thick bed of till before striking water-bearing sand or gTavel. A similar sheet of till is passed through on the plain between the middle and oiiter ridges in southern Champaign County and on the inner ridge and bordenng plains in eastern Champaign County. A boring at Sidney on a plain north of the inner ridge, made in 1884 by the Sidney Mineral Company, penetrated biit 9o feet of drift, as follows:^ Section of drift in a boring at Sidney, Illinois. Feet. Yellow clay, containing few pebbles 17 Blue clay, containing few pebbles 18 Pebbly blue clay 5 Pebbly yellow clay 15 Sand and gravel 5 Peljbly cbiy 35 Tntal drift 95 In northeast Douglas Count}*, aud thence eastward along tlie moraine, wells are usually but 30 to 40 feet in depth and very rarely reach a depth of 100 feet. They are mainly through till, except in southeastern Vermilion County, where in some cases considerable gravel is penetrated. A well on the north face of the Inner Ridge, a short distance east of the State line, at the residence of Mr. Malone, did not reach the bottom of the drift at a depth of 241 feet, and failed to obtain water. The well mouth has an altitude about 625 feet above tide, or 160 feet above the Wabash River. The following section was furnished by Jlr. Malone : Section of Malone' s icell near Eugene, Indiana. Feet. Pebbly yellow clay 15 Pebbly blue clay 35 Dry sand and gravel 10 Hard pebbly gray clay (probably lllinoian) 55 Alternations of clay with sand aud gravel in thin beds 125 Total depth 240 F. H. Bradley has published the following section of drift exposed on a branch of Johnson's Creek, near Newport, Indiana:" • For this section I am indebted to Prof. C. W. Rolfe. ■^Geoloiiy of Indiana, 1869, p. 141. THE CHAMPAIGN MOEAIJSIIO SYSTEM. 237 Section of drift near Neioport, Indiana. Feet. In. Bowlder clay, with pebbles of Silurian limestone autl trap 30 Yellow clay, with fragments of coal, shale, sandstone, etc 4 Bowlder clay, with pebbles of Silurian limestone 25 Ferruginous sand Streak. Bowlder clay, from the northwest, with pebbles of various metamorphic rocks and trap, and nuggets of native copper 50 Total exposure. 105 4 East of the Wabash, in Parke Coiinty, wells along the outer or main belt and on the plain north of it are seldom more than 30 feet in depth. They pass through about 15 feet of yellow till, beneath which some of them enter blue till, while others enter gravel. Thin beds of sand or gravel are often found associated with the yellow as well as the blue till. Wells in western Montgomery County are in some cases sunk to a depth of 50 or 75 feet, mainly through blue till. On the plain in Fountain County, and also on the inner morainic ridge, wells seldom reach a depth of 50 feet, and usually obtain water without entering rock, there being beds of water-bearing sand or gravel associated with the till sheet. CHAKACTBR OF OUTWASH. As a rule the plains outside the ridges of this morainic system show scarcely any sand or gravel outwash from the moraine, and there appears to have been only a gentle movement of waters from the ice margin south- ward down the valleys. At the point where the Sangamon River emerges from the moraine in the village of Mahomet there is a gravelly outwash having a depth of 6 or 7 feet, which caps the till plain on the immediate border of the valley. Expo- sures are to be seen east of the railway station and also at several points in the village. The exposures east of the railway station show a bed of loess- like silt about 3 feet in thickness immediately below the gravel, and beneath this a brownish-yellow till. The loess-like silt is similar to that which covers the plains quite extensively in this region. The gravel overwash is of very limited extent, reaching out scarcely a half mile from the south border of the moraine. It merges into low gravelly knolls on the border of the moraine. These features seem to leave no question of the gravel being derived from the ice sheet during the formation of the moraine. Attention has already been called to a gravelh^ tract along the Sangamon 238 THE ILLINOIS GLACIAL LOBE. River below this point. The small amount of outwash shown at the border of the moraine seems to make it doubtful if the gravel belt along the river was chiefly formed as morainic outwash. The gravel may be largely a residue from the cutting down of the sheet of drift outside the moraine. Kaskaskia and Embarras valleys have, as a laile, either silt or till banks where they border the ridges of this morainic system. It is probable that the ice sheet had feeble outwash at these valleys, as they are favorably situated for receiving any outwash which may have been contributed from the moraine, the course of the Kaskaskia being for several miles but a short distance outside the Outer Ridge and the com-se of the Embarras being for an even greater distance just outside the Middle Ridge. Near the head of Bruillett's Creek, in northern Edgar County, the plain outside the moraine has an area of several square miles which is underlain by gravel. Tributaries of Bruillett's Creek lead down from the moraine into this plain and lose their waters in its gravel. In some cases these streams do not maintain a channel in this plain. It is not entirely certain that this ffravel is an outwash from the moraine, since the moraine itself is of a stiff clayey constitution on the immediate borders of the gravelly plain. If the moraine had a gravelly constitution on this border, as it does at Mahomet, tlie case would seem more certain.' Along the Wabash River Valley extensive gravel teiTaces occur both above and below the points where the ridges of this morainic system cross. Possibly a portion of the gi-avel connects with this morainic system, but by far the larger part connects with moraines of later date which cross farther up the valley. Near Bloomingdale, Indiana, a gravel-filled valley not now occupied by a stream leads southward from the moraine across Leatherwood Creek to the valley of Rocky Run, a distance of 2 miles, and thence continues down Rocky Run to the Wabash Valley. The portion not occupied by a stream is bordered by bluffs 30 to 50 feet in height, and has a width of from one- third to one-half mile. The relation of this valley to the Champaign morainic system is not definitely settled. It is perhaps an interglacial val- ley, whose upper course has been oveiridden and concealed by the Cham- ])aign drift sheet. The gravel filling in its bottom may prove to be an outwash from the moraine, though this is not entirely certain. It is not evident why Leatlierwood Creek chose a passage westward instead of turn- THE CHAMPAIGN MORAIIsriO SYSTEM. 239 ing- down this valley. Its flood plain is now only about 20 feet below the level of the bottom of the abandoned valley at the point where it crosses it, and the difficulties of opening a westward passage seem greater than would be necessary to have adopted the course of the abandoned valley. On the outer border of the Inner Ridge in Shawnee Township, Fountain County, Indiana, just north of the point where Coal Creek is deflected southward by the morainic ridge, there is a small plain underlain with gravel which is perhaps an overwash from the moraine. There is also considerable gravel along Coal Creek below the bend, preserved in terrace-like remnants standing 35 to 50 feet above the present stream. It is not determined, however, whether this gravel is an outwash from the drift ridge or is merely a residue formed in the cutting of the valley. Against the latter view it may be said that the present stream seems scarcely adequate to transport gravel deposits of such coarseness as are here displayed. Sugar Creek Valley carries gravel terraces in its lower course, but these terraces are as 'well developed in portions of the valley above the crossing of this morainic system as below that point. The lower course of the creek is on the inner border of the Outer Ridge of this morainic system, and thus is very unfavorably situated for receiving an outwash. Further- more, the gravel terraces seem to be built up in a valley which had been excavated in the Champaign drift sheet. It is hig-hly probable, therefore, that these gravel terraces have no connection with the Champaign morainic system, but are of later date. ASSOCIATED TILL PLAINS. Between the ridges of this morainic system there are, as alread}^ noted, till plains ranging in width from 1 or 2 up to about 10 miles in the Illinois portion, and reaching a width of nearly 20 miles in Parke and Fountain counties, Indiana. On these plains there are occasional low knolls, but the general surface is much smoother than that of the bordering morainic ridges. Another plain having greater extent occupies the interval between the Inner Ridge of the Chamj)aign morainic system and the Outer Ridge of the Bloomingtou morainic system. Its width at the northwest, near the corners of Ford, McLean, and Champaign counties, is about 15 miles, and this width is maintained across Champaign County. In VeiTuilion County, 240 THE ILLINOIS GLACIAL LOBE. Illinois, it decreases to 10 or 12 miles, and continues into Indiana with about the same width. On this plain, as on the plains between the ridges of the Champaign morainic system, the surface is generally much smoother than on the ridges. There are occasional knolls, however, which reach a height of 30 feet or more, and swells 5 to 10 feet in height are found in nearly every township. The thickness of di'ift differs from that in the morainic ridges only by the measure of the relief of the ridges. In the Indiana portion, and for some distance westward into Illinois, rock is often encountered at a depth of 50 feet or less, but in Champaign County the drift tliickness increases to 200 feet or more, for the thickness, as on the ridges, is much greater in the western than in the eastern portion of the county. The thick drift continues northwestward into Ford and McLean counties. There is beneath these plains a buried soil found at a depth of 75 to 100 feet or less in Champaign County, and at 25 to 60 feet in counties farther east. This appears to be at the base of the Shelby^'ille drift sheet. As yet no soil has been discovered between the Champaign and Shelbj^ville sheets. The drift appears to be composed more largely of till beneath these plains than in the moraines, but sufficient gravel and sand occur to afford water for wells throughout most of the region. SECTION III. BLOOMKVGTON^ MORAIIS^C SYSTEM. The system of moraines to which the name Bloomington is applied is scarcely surpassed in strength of development or in complexity of features by any other morainic system in the early Wisconsin series. It is one of the most important in the series, not only because of its strength of develop- ment but because it extends in places beyond the earlier moraines of the series, and for a distance of about 120 miles constitutes the border of the Wisconsin drift. It receives its name from the city of Bloomington, Illinois, which stands on a prominent portion of its chief ridge. The name seems especially pertinent since Bloomington is situated near the middle point of this morainic loop, just as Shelbyville is situated near the middle point of the Shelbyville loop. Where best developed there are two bulky ridges, constituting the outer part of the system, and two smaller ridges constituting the inner part. The four ridges are not continuously developed, however, since the}- inter- THE BLOOMINGTON MORAINIC SYSTEM. 241 lock in places, and the weaker ridges fade out at intervals. In places each of the bulky ridges are double crested and more or less distinctly separable, making four ridges aside from the two weaker ones. The system may be traced satisfactorily for a distance of aboiit 300 miles from the northern tier of counties in Illinois around to the western tier m Indiana. In northern Illinois this system becomes so closely associated with other systems in a composite belt that further tracing seems impracticable. This northern portion from Peoria County northward overrides or becomes united with the Shelbyville morainic system, so that the latter is no longer traceable. In western Indiana the Bloomington system is overridden by moraines of late Wisconsin date, which have partially concealed its further course. DISTRIBUTION. The Bloomington morainic system (carrying with it perhaps the Shel- byAalle system) separates from the composite belt of moraines in northern Kane County and passes in a course slightly south of west across central Dekalb County, occupying a space about 12 or 14 miles in width. Its outer and inner borders are each characterized by a definite ridge. On the borders of Dekalb and Lee counties, in the vicinity of Shabbona and Paw- paw, it becomes narrowed to only 6 miles, owing to a reentrant angle on the outer border. Thus far the weak inner members of the system are undeveloped. Continuing southwestward it expands in northern Bureau County to a width of 18 or 20 miles. This does not include a weak inner member of the system which sets in near Earlville and leads southward along a line several miles east of the inner border of the main ridges, and whose course is discussed below. The ridge along the inner border dies out in eastern Bureau County, so that upon approaching the Illinois River in southern Bureau County only the ridge on the outer border of the sys- tem is maintained in strength. The ridge which dies out in eastern Bureau Count}^ a^jparently finds continuation in a ridge that crosses northern McLean County, as noted below. The bulky ridge passes southward through west- em Marshall and northeastern Peoria counties and occupies a width of several miles. The portion in northeastern Peoria County is well shown in the Dunlap topographic sheet, where it forms the divide between Kickapoo Creek and smaller tributaries of the Illinois that flow eastward into the river. The Shelbyville moraine emerg-es from beneath it in eastern Stark MON XXXVIII 16 242 THE ILLINOIS GLACIAL LOBE. County, as previously noted. This feature also may be seen on the Dun- lap sheet, the point of emergence being near Lawn Ridge. The Blooming-- ton ridge crosses the Illinois River just above the city of Peoria and passes southeastward across northern Tazewell County with an elevated semi- morainic tract on its eastern border, extending into western Woodford County. In northwestern McLean County, immediately east of the Macki- naw River, two prominent ridges are found in place of the one ridg'e farther west. They are closely associated and lead across the county in a cur^dng course bearing south of east in the western portion and north of east in the eastern portion. The ridges are more closely associated in tlie eastern than in the western portion of the county, but nowhere occupy a belt more than 10 miles in width. In the eastern portion the width is not more than 6 miles. The plane tract between them is only 1 or 2 miles in width. In Ford County a slight reentrant angle is formed immediately north of Gib- son, and the morainic system which bears northeastward in the western part of the county changes abruptly to a southeastward course in the cen- ti-al portion. The inner border of the reentrant portion extends northward as far as Chatsworth and Piper. From this reentrant angle the outer border leads from Gibson southeastward across northeastern Champaign County, passing near Rantoul and Gifford, and enters Vermilion County abr)ut 3 miles northwest of Fithian. It's course is thence directly eastward across the countj^ into Indiana, passing a couple of miles nortli of Dan^nlle, Illinois. It is very clearly defined on the DauAalle topographic sheet. In Warren County, Indiana, its course changes to north of east, following nearly the north bluff of AVabash River to Pine Creek Valley, near Williamsport. The moi'aine here swings northward and is traceable as far as eastern Benton County, where it dies away in a gently undulating plain. This system is overridden by a series of weak bowldery moraines of the late Wisconsin series in northern Warren and southern Benton counties, but is not greatly obscured along the line of the outer belts. Greater obliteration apparently occuiTed a few miles back from the late Wisconsin border. However, the Bloomington system apparently iinds its continuation in a belt of very thick drift which leads from Benton County, Indiana, southeastward across Tip- pecanoe, Clinton, Boone, and Hamilton counties, and thence eastwai-d into Ohio. But tliis belt is outside tlie territory embraced in the present report. Returning to the reentrant angle in Ford County, Illinois, the inner border of the Bloomington system is found to i)ass southward from I'iper, THE BLOOMINGTOF MOEAINIO SYSTEM. 243 near Thawville and Loda, and thence to swing eastward in a curving course through eastern Ford, northern Vermilion, and southeastern IroqiTois counties. The inner bulky ridge of the system continues eastward to Fowler, Indiana, where it terminates very abruptly a few miles west of the outer ridge. From the reentrant ang-le in Ford County two weak ridges are trace- able westward. The inner or Cha,tsworth-Cayuga Ridge leads from Chats- worth north of west to Cayuga, where for a few miles it passes beneath, or is nearly -obscured by, the Marseilles moraine. Near Blackstone, in north- ern Livingston County, a ridge which is probably its continuation emerges from beneath that moraine and passes northwestward nearly parallel with the Vermilion River through or near Kernan, Grand Ridge, and Farm Ridge villages to the Illinois Valley at Utica. For a part of the course it forms the divide between •the Illinois and Vermilion rivers and may easily be traced on the Ottawa and Lasalle topographic sheets. This northern part is known as Grand or Farm Ridge. North from the Illinois its course is slightly east of north from Utica past Eariville, where it fades out near the inner margin of the main moraine in southern Dekalb County. It is well shown in the east part of the Lasalle sheet and northwest part of the Ottawa sheet. The gaps in this ridge are narrow, and are discussed below (p. 259). This ridge probably finds its correlative east of the Ford County reentrant angle in a belt of undulating or slightly ridged drift leading east- ward across central Iroquois County. The latter belt, however, scarcely constitutes a definite moraine, being distinctly ridged only for a few miles along the north border of Sugar Creek east from Milford. It disappears beneath a moraine of late Wisconsin age near the State line south of Sheldon, Illinois. The other ridge which leads west from the Ford County reentrant angle, commonly known as Cropsey Ridge, from a villag-e situated on it, is distinctly traceable across the northern part of McLean County, where it constitutes the water parting between Mackinaw and Vei'milion rivers. It fades out in the vicinity of Gridley, and is not definitely developed toward the west or north until the Illinois Valley is passed. It seems, however, to be a continuation of the belt which fades out in eastern Bureau County, as noted above. The character of the topography in the interval between these ridges is discussed below (p. 281). 244 THE ILLINOIS GLACIAL LOBE. RELIEF. The relief on the outer border seldom falls below 50 feet and in places approaches 200 feet. The average relief is probably 75 or 100 feet. The least relief is found in j)ortions of Ford and Champaign counties, Illinois, where it is about 50 feet. The greatest relief is found in southern Lee and northern Bureau counties, where the moraine is bordered on the west by the Grreen Eiver Basin. The moraine here has an altitude of 900 to 1,000 feet or more above tide, while the basin on the immediate borders of the naoraine rises from scarcely 700 feet at the west to about 850 feet at the east, thus giving the moraine a relief of 150 to 200 feet. Between the ridges of this system there is very little depression in Dekalb and Lee counties. But on the inner border of the system in these counties there is nearly as pronounced relief .as on the outer border. Indeed, in places it exceeds that on the outer border, and probably it averag-es 100 feet. The relief on the inner border continues jDrominent southwestward into Bureau County, but falls off rapidly in that county, becoming scarcely perceptible in the vicinity of the Illinois River. The outer ridge, however, maintains its great relief throughout Bureau County and rises 100 feet or more above the plain and lower ridge on its inner border in the eastern part of the county. In southern Bureau, western Marshall, and northeastern Peoria counties it stands 150 feet or more above the narrow upland between it and the Illinois Valley. This prominent ridge probably includes both the Shelbyville and Bloomington systems, for the former separates from it in eastern Stark county, as noted above. Upon crossing the Illinois into Woodford County the uplands on the inner border of the Bloomington moraine are found to stand but a few feet lower than the crest, and eastward from this county there is generally a very gradual descent on the inner border of the main ridges, a descent seldom exceeding 25 or 30 feet to the mile. The small ridge which leads across northern McLean County has a relief of but 30 to 50 feet on its outer border and a gradual descent on its inner border. The ridge leading northwestward from Chatsworth to Earl- ville usually rises 30 to 50 feet above the outer border, but reaches about 75 feet in places in central Lasalle County. The relief on the inner bor- der is nearly as great as on the outer, but is usually more gradual THE BLOOMINGTOIf MORAHSTIO SYSTEM. 245 KANGE IN ALTITUDE. This morainic system presents a range in altitude of only about 300 feet, its highest points being slightly more than 1,000 feet above tide, while few points, aside from valleys, fall below 700 feet. The range, both along the crest and along the immediate outer border, is set forth by counties in the followingr table: Table slioicing range in altitude of the Bloomington morainic system. County. Dekalb (Illinois) . ... Ogle (Illinois) Lee (Illinois) Bureau (Illinois) Marshall (Illinois) . . . Peoria (Illinois) Tazewell (Illinois)..-. McLean (Illinois) Ford (Illinois) Champaign (Illinois) Vermilion (Illinois) . Warren (Indiana) ... Benton (Indiana) Crest, above tide. Feet. 875- 975 875- 940 900-1, 025 700- 989 800- 700- 700- 775- 775- 750- 680- 700- 750- 900 830 825 913 860 830 790 775 825 Outer border, above tide. Feet. 775-850 790-820 740-860 675-825 700-800 650-775 650-725 700-820 740-760 700-760 630-700 625-675 675-725 SURFACE CONTOUES. A general statement can scarcely be made which will set forth the vari- ations in contour or topographic expression of this morainic system through- out its entire leng-th. It is found convenient to discuss it in sections, beginning at the north and proceeding southward. The first section embraces the portion between western Kane County, where this system separates from the morainic complex of northern Illinois, and the head ot Bureau Creek in northeastern Lee County, a section 35 or 40 miles in length. The second section (about 50 miles) embraces the portion drained by Bureau Creek and its tributaries. The third section (40 miles) embraces the portion along the west side of the Illinois in Bureau, Marshall, and Peoria counties. The fourth section (20 miles) embraces the portion 246 THE ILLINOIS GLACIAL LOBE. between the Illinois and ]\Iackinaw rivers in Tazewell and Woodford coun- ties. The fifth section (50 to 55 miles) embraces the portion between the Mackinaw River and the reentrant angle in Ford Connty. The sixth sec- tion (nearlv 100 miles) embraces the portion between the reentrant ang-le in Ford CouutA*, Illinois, and points where this system passes beneath the moraines of late Wisconsin age in Benton and Warren counties, Indiana. For the distribution of the several sections see PL VI. Between western Kane County and the head of Bureau Creek. Tlie SeCtloU betWeCU WeSt- ern Kane County, Illinois, and the head of Bureau Creek, taken as a whole, consists of a mass of di-ift standing 50 to 100 feet or more above the plains on the northwest and southeast borders, and occupying a width of 6 to 15 miles. Much of the surface is nearly plane, and differs but little from that of the plain on the southeast. ■ There is, however, scarcely a square mile in which knolls 10 to 20 feet high are not present, and also shallow basins which contain ponds. The decidedly morainic expression is confined to three somewhat naiTOw belts, one on the outer border, another on the inner border, and an intermediate less definite belt The belt on the outer border leads fi'om Hampshire westward into Dekalb County, crossing South Kishwaukee River just above the bend near Genoa, and then curves around to the southwest and south in western De- kalb and southeastern Ogle and eastern Lee counties. Its width is seldom more than 3 miles, and in places scarcely reaches 2 miles. From Hamp- shire Avest to the Kishwaukee River it is less prominently ridged tlian west of that stream, there being a rise of scai-cely 50 feet to its highest points from the plain on the north. This ^jortion, however, has about as much morainic expression as the higher part of the border to the west. Knolls 10 to 25 feet are closely aggregated and inclose shallow basins. The basins are usually depressed but 5 or 6 feet below the lowest part of their rims, and occupy only an acre or two. Occasionally a basin occupying as much as 10 acres is to be seen. From South Kishwaukee River south \\'estward through western Dekalb and southeastern Ogle counties, the outer belt consists of a series of narrow ridges with shallow sags between them, each trending with the entire belt in a NE.-SW. course, changing to southward in Ogle County. The ridires are each a mile or less in width and stand 30 to 50 feet above the intervening sags. There are in places four ridges, but usually only two or three. Each ridge has gentle undulations on its crest and slope, seldom THE BLOOMINGTOl^r MORAHsTIC SYSTEM. 247 more than 10 or 15 feet high. This breaking up of a morainic belt into several ridges at a salient curve is a common featm-e in this and other morainic systems. In Ogle and northeastern Lee counties sloughs are a conspicuous feature among the knolls. This outer belt is interrupted by several gaps, occupied by streams, which head on its inner border and pass through it to the lower outlying districts. Named in order from east to west there are the following: Coon Creek, South Kishwaukee River, Owen's Creek, Killbuck Creek, Kite River, and two branches of Willow Creek. The crest of the morainic belt is absent for a mile or more at each of these valleys. Apparently there were gaps of this width in it prior to the open- ing of the drainage lines, for the slopes bordering the valleys carry knolls and shallow basins such as characterize slightly eroded portions of the belt. As shown below, these gaps were probably formed by streams issuing from the ice sheet. The valley bottoms range in width from 60 rods up to fully one-half mile, the broadest being at Kishwaukee River. The middle belt appears in western Kane County at Burlington. A morainic spur is found to lead southwestward from the inner border of the outer belt into eastern Dekalb County, and to fade away 2 miles east of Sycamore. It is about 1 mile in width, and is characterized by numerous basins and low knolls, which give it fully as strong expression as the neighbor- ing portion of the outer belt, from which it is separated by a narrow plain 1 J or 2 miles in width. There is also a basement ridge wdth a relief of perhaps 20 feet. For several miles west from the points where the Burlington spur dies out, knolls 10 to 26 feet high are rather numerous and constitute a probable line of continuation. Near Malta a definite ridge appears, which leads southwestward to the outer belt in the southwest corner of Malta Township,. Dekalb County, and thence southward along the east border of the outer belt, through western Milan and northwestern Shabbona town- ships, passing just east of the village of Lee. For 3 or 4 miles in western Milan Township it is combined with the outer belt, but elsewhere it is separated from it by a narrow plane tract about a mile in average width. In western Shabbona Township, Dekalb County, it becomes completely united with the outer belt. This ridge, like the Burlington spur, is about a mile in average width. It has a relief of 20 to 40 feet above the bordering plane tracts. Its surface is gently undulating, but basins are rare, except where it is closely associated with the outer belt in Milan Township. The 248 THE ILLINOIS GLACIAL LOBE. altitude of the ridge just discussed is about as great as that of the outer belt, aud it constitutes the source of several of the streams which lead through the outer belt, viz, Owen's Creek, Killbuck Creek, Kite River, and Willow Creek. By returning again to western Kane County, to Elburn, where the inner member leaves the composite belt, and tracing the moraine Avestward, it is found to take a more direct course than the outer one. It leads nearly due west for about 10 miles, being throughout much of the distance between Elburn and Cortland in ^sdew from the Chicago and Northwestern Railway. Immediately south of Cortland it changes to a southwestward trend and joins the outer belt for a few miles in southwestern Shabbona Township, Dekalb County, and eastern Wyoming Township, Lee County, at the southwestern limits of the section of the morainic system under discussion. Throughout much of this distance it has a well-defined crest and occupies a widtli of 1 to 2 miles. For a few miles at the curving portion southwest of Cortland it presents two ridges separated by a sag or plane tract about a mile in width that stands 20 to 30 feet below the level of the crests of the ridges. In western Kane County several sharp gravel knolls 30 to 40 feet in height are found in this belt, and occasionally sharp knolls are found in it farther west. As a rule, howcA^er, its undulations are gentle. The crest stands only 20 to 40 feet above the district to the north, but there is a descent of nearly 100 feet within a couple of miles on the south border. On the slope there are low knolls and a gently undulating surface. At its junction with the outer border belt in Shabbona and Wyoming townships numerous basins and sharp knolls occiu-. The knolls are in some cases 30 or 40 feet in height, though usually 20 feet or less. This inner moraine forms the divide between South Kishwaukee River and several tributaries of Fox River, and is not crossed by any stream east of its junction with tlic outer belt. Near the point of junction south of Shabbona it is crossed by Indian C*reek, a tributary of Fox River, which headKS in the combined belt aud flows southwestward. In its course through this moraine the creek winds aI)out greatly among the knolls and has not so broad a passage as is afforded tlie stniaius wliich lead northward across the outer belt. In the Bureau Creek drainage basin. TllC SCCOud SGCtioU of tllC BloOmiugtOU morainic system, which embraces tlic ilrainage basin of Bureau Creek, maintains a belt (in its outer border fully as jironiincut as that of the THE BLOOMINGTOjST MOEAINIC SYSTEM. 249 section just discussed, but its inner-border belt, as noted above, loses its strength in eastern Bureau County, and in the vicinity of the Illinois River rises only a few feet above the inner-border plain. With the decline of this belt a still later belt appears on the plain to the east, as noted above. The two main belts are closely associated for about 20 miles in southern Lee County, being separated only by a narrow plain 1 to 2 miles m width, tlii'ough the midst of which Bureau Creek has its jjassage. They then diverge, the course of the inner one being slightly west of south, through eastern Bureau County, while the outer continues with a course slightly south of west along the borders of Lee and Bureau counties for a distance of 20 miles. It there turns southward through central Bureau County, curving around the western border of the Bureau Creek Basin and passing just west of Wyanet and Tiskilwa. The plain between the moraines in Bureau County has a gently undulating surface and stands nearly as hig'h as the inner moraine, but is much lower than the outer one. There is, in this plain, a slight tendency to ridging, with NE.-SW. trend, which to some extent governs the course of sti'eams. The outer belt throughout its course in southern Lee and northern and central Bureau counties maintains a width of 4 to 6 miles. This includes gradual slopes which culminate in a well-defined narrow-crested ridge that is developed along a considerable portion of the section under discussion. The crested ridge usually occupies a breadth of less than a mile, and stands 30 to 50 feet above the less sharply ridged portions on its borders. In places the sharp crest is absent and the gradual slopes occupy its entire breadth. Near Wyanet a narrow depression as low as the outer-border plain interrupts this ridge and furnishes a passage for the Hennepin Canal, now under construction. This depression is not an open valley, but has morainic knolls on its bottom and slopes. In southern Lee County the knolls and undulations on the slopes of the moraine are much less conspicuous than in Bureau County, their height usually being but 10 or 20 feet, while in Bureau Count}^ they frequently attain a height of 30 or 40 feet. Basins are common only in central Bureau County, though they are found occasionally in other parts of the moraines. The deepest are only 10 or 15 feet below the bordering rims, and their area is seldom more than an acre or so each. On the outer face of the moraine in Lee Countv, from the vicinity of the Third Principal 250 THE ILLINOIS GLACIAL LOBE. Meridian westward to northern Bureau County, there are numerous sand knolls and ridges, 10 to 40 feet in height, which add greatl}^ to the inequal- ities of the surface. These sand accumulations follow the lines of ridges or knolls in the moraine, rather than the depressions between them. The sand is still subject to slight moditication by wind action, and its ridg-es, as well as its presence on the moraine, are probably the result of wind transportation from the Green River Basin, which borders this portion of the moraine on the west. The inner belt of this system, as noted above, is merged with the outer from the vicinity of Shabbona southwestward to Pawpaw, and presents a knob-and-basin topography along the line of junction. Upon separating from the outer belt the topograpliy changes to gentle undulations, and there is also a tendency to ridging in the line of the belt. In places a cross section would lead over at least three nearly parallel ridges separated by narrow sags, the Avhole series occupying a width of scarcely 2 miles. The ridges are, however, not distinctly maintained for long distances, but are at intervals crowded together. These ridges are of about equal height and rise only 25 to 50 feet above the plain on their outer border. The relief on the inner or southeast border is nearly 150 feet in eastern Lee County, and this great relief is maintained for 10 or 12 miles southwestward in south- eastern Lee and northwestern Lasalle counties. Upon Entering Bureau County the relief decreases rapidly, as already noted, but the expression continues as strong as in the portion having greater relief Knolls 20 feet or more in height are closely aggregated, and are disposed in chains trending in line with the belt. Upon approaching the Illinois Valley they become more scattering, and the belt fades out about 2 miles north of Depue. The feebly developed portion ()f this belt is shown in the northwest corner of the Lasalle topograpliic sheet and in the eastern part of the Hennepin sheet between East Bureiiu and Brusli creeks. The ridge which leads south- ward from Earlville past Utica, a few niiles east of this moraine, is discussed farther on, as is also the topography in the line of continuation of this moraine in Putnam, Marshall, Woodford, and McLean counties. (See pp. 261, 281.) In Bureau, Marshall, and Peoria counties TllC third SCCtioU of thc BloOmillS'tOn morainic system onibr:ices tlu^ })ortion of the moraine west of the Illinois River in Bureau, MarsliMll, nnd Peiiri;i counties. This consists niainh' of a large ridge, 4 to 6 miles in \vi(hli ninl 100 feet or more in height above THE BLOOMIKGTOJSr MOEAINIO SYSTEM. 251 the districts on the west and an even greater height above the narrow plain between the ridge and the river bkiff. Aside from this main ridge there are minor ridges trending parallel with it on its inner or eastern border. These minor ridges are a mile or less in width, 25 to 50 feet in height, and are maintained for only a few miles in a place. The surfaces are much smoother than that of the main ridge. They are similar to the slight ridgings found between the inner and oiiter belts in eastern Bureau County, and, like those ridg'es, have an influence on the course of drainage. One of the most con- spicuous instances of the governing of drainage is that of Senachwine Creek, in southwestern Marshall County, which owes its southward course to a low drift ridge on its east border. The main ridge has a topography similar to that of its northern con- tinuation in central and northern Bureau County. In places a sharplj?^ outlined crest is developed, but usually the higher part of the ridge is broken up into knolls and sharp disjointed ridges which rise 20 to 40 feet above neighboring basins or sags. Shallow basins are a common feature along this portion of the moraine. On the outer face the border is irregular, being indented hj valley-like extensions of the outer-border plain, which in some cases reach a mile or more back into the moraine. Between these indentations there are spur-like projections. The moraine is nowhere cut through by any of these low tracts, though a line along its crest occasion- ally oscillates 100 feet or more within a space of 2 or 3 miles. On the whole, this section is scarcely surpassed in strength by any other portion of this morainic system. Between the Illinois and Mackinaw rivers. Tlie SeCtioU embraCCd betweCU the Illi- nois and Mackinaw rivers has a well-defined outer or southwest border, but its inner or northeast border is difiicult to determine. It merges on the northeast into an elevated tract with a gently undulating surface, whose general altitude is about as great as tha,t of the portion of the belt which presents stronger morainic expression. This elevated tract extends as far east as Cazenovia. Should the entire district between Cazenovia and the outer border be included in the moraine, it would have a breadth of about 14 miles, or more than twice the breadth of the bulky outer ridge formed on the west side of the river. The strongly morainic expression is confined, however, to the outer or southwest face in a belt only 3 or 4 miles in width. This face presents a series of drift billows 20 to 30 feet in height, 252 THE 1LLI5TOIS GLACIAL LOBE. among whicli are sags and shallow basins. The swells are usually closely aggregated, but in places nearly plane tracts of a square mile or more appear in the midst of this belt. An instance of such a plane tract may be seen south of Deer Creek callage. The elevated tract on the northeast border of this moraine has only occasional low swells 10 or 15 feet in height, the greater part of the surface being as smooth as the plains farther noi'th and east, and differing from them only 50 to 75 feet in altitude. The descent is made in a distance of 2 or 3 miles, and is therefore so gradual as to be scarcelv perceptible to the eye. The relief on the outer border is more conspicuous than on the inner, a rise of 100 feet being made in about 2 miles at the prominent parts of the moraine. This border is also made conspicuous by the change from the A^ery flat surface outside the moraine to the billowy surface presented by its outer face. Between Mackinaw River and the Ford County reentrant. EaSt of tllC MackiuaW River, near the borders of Woodfoi'd, McLean, and Tazewell counties, the Bloom- ington morainic system presents two well-defined bulky ridges which are separated by a narrow plain or sag 1 or 2 miles or more in width. These ridges are distinctly maintained from the extreme northwest corner of McLean County eastward to Padua, a distance of nearly 30 miles, beyond which, for 20 to 25 miles, to the Ford County reentrant, they are combined into a single belt. The inner ridge enters McLean Coi;nty from Woodford County near the line of the third principal meridian and passes soutlieastward through Normal and thence eastward through Barnes to Padua, where it becomes combined with the outer ridge. It has a general width of 2 or 3 miles and rises 30 to 50 feet above the sag or plain on its south border. The surface is billowy, Avith oscillations of 20 or 30 feet between the higher swells and neighboring sags. Many smaller swells occur, with a height of 5 or 10 feet. The slope of these swells is usually gentle, and knolls 20 feet in heiglit occupy several acres. In j^laces this moraine presents a sharply outlined crest; a conspicuous instance Avas noted northwest of Padua, Avhere a ridge-like crest with a width of only one-fourtli to one-half mile stands about 50 feet above the tracts on either side. As a rule, however, the higlier_])()rtion of this belt consistif of a series of swells similar to those found on tlie slojjes. For several miles nortli from this inner ridge the siu'face is THE BLOOMINGTOlSr MORAINIC SYSTEM. 253 gentl)^ undulating' and dotted with occasional knolls of considerable promi- nence, the highest knolls rising 30 to 40 feet above border districts. The outer ridge crosses Mackinaw River immediately above Mack- inaw village and leads southeastward to Bloomington and thence eastward to its point of junction with the inner ridge near Padua. It has a breadth of about 3 miles. It is crossed by several streams which head in the inner ridge, among which are three of the headwater branches of Sugar Creek, two headwater branches of Kickapoo Greek, and one headwater branch of Salt Creek. Sangamon River also leads tlu-ough it, east from the junction with the inner ridge. There are thus seven streams crossing it within a space of 35 or 40 miles, admitting only about 5 miles average distance between streams. The gaps through Avhich these streams pass, each cause a break in the crest of the moraine nearly a mile in width. They do not appear to be entirely erosion gaps, for the morainic swells occupy them down nearly to the level of the streams, or about 75 to 100 feet below the level of the neighboring crests. It is probable that streams issuing from the ice sheet at the time the moraine was forming prevented the accumulation of heaver deposits in the vicinity of their points of departure from the ice. Between these gaps the moraine usually has a well-defined crest and gently undulating surface. The crest lies near the outer border of the moraine, the outer face being, as a rule, much more abrupt than the inner. As the moraine, where not interrupted by gaps, has a relief of 100 feet, the outer face often presents the abruptness of a river bluff. It differs, however, from a river bluff in the absence of erosion contours, there being instead a billowy slope, such as characterizes moraines. The erosion effected by streams since the withdrawal of the ice sheet is very inconspicuous com- pared with the inequalities of drift aggregation. The crest is usually so gently undulating as scarcely to suggest the strength of the moraine. It is not uncommon to find it so level for a space of one-fourth to one-half mile in width and for several miles in length that artificial ditching is neces- sary to give it good drainage. In such places there are usually shallow basins, 2 to 5 feet in depth, occupying an acre or more each, which add to the imperfection of drainage. The crest varies considerably in altitude independent of the gaps just mentioned, its highest points being about 900 feet above tide and its lowest about 800 feet. The range of 100 feet in 254 THE ILLINOIS GLACIAL LOBE. altitude, however, occupies a space of 1 to 2 miles or more, and hence is not conspicuous. The slopes usually present more undulations than the crest, but their swells seldom exceed 20 feet in height. The combined belt east from Padua differs from the separate belts farther west in presenting greater complexity of features. Between Padua and Arrowsmith the trend of the principal ridges is northwest to southeast. One ridge with this trend passes immediately west of Ellsworth and consti- tutes the divide between Sangamon River and Kickapoo Creek. Another ridge leads into Arrowsmith from the northwest, which separates the Sanga- mon from the Mackinaw. From the -sncinity of Arrowsmith eastward to the reentrant angle in Ford County the trend of ridges is southwest to northeast, or nearly at right angles with those west of An-owsmith. The ridges just mentioned are low, with a relief of but 30 or 40 feet. There is a prominent crest along the south border of the combined belt which is interrupted by a small gap at the Sangamon Valley. It stands about 100 feet above the plain outside the moraine, and rises from that plain with the abruptness of a bluff line. The Sangamon River winds about through sags among ridges until it emerges from this morainic belt. Aside from the ridges and broad sags the moraine is characterized by a multitude of gentle swells 10 or 15 feet in height, among which there are shallow sags and occasional basins. The reentrant in Ford County. — 111 the reentrant auglc ill Ford couuty the ridges on the west are crowded together in a single belt, but those on the east are in pait separated b}^ narrow strips of level marshy land which trend witli the belt from north-northwest to south-southeast. The topography of the greater part of the reentrant portion is of a gentle swell-and-sag type, with undulations of only 15 or 20 feet. The ridges have definite crest lines standing about 50 feet above the marshy plains which separate them. In southeastern Livingston Count}', however, at the extreme north end of the reentrant, a sharp knob-and-basiu topography is developed, in which knolls rise abruptly 30 or 40 feet above the basins inclosed among them. There are several small lakes and ponds among the morainic knolls, the largest of wliicli occupy areas of 40 acres or more, but the majority occupy only a few acres each. From this jioiiit of the reentrant angle there is more or less knob-and-basiu topography develo])ed along the inner or northeastern slope of the moraine tln-oughout its southeastward course THE BLOOMINGTOISr MOEAINIO SYSTEM. 255 in eastern Ford and southwestern Iroquois counties. It is confined to a belt about 3 miles in width, and probably half the surface is of this type. The remainder is of a gentle swell-and-sag type. The expression is more subdued than at the point of the reentrant angle, and knolls exceeding 30 feet in height are rare. The basins are seldom occupied by j)onds except in wet seasons. The contrast between this knob-and-basin tract and the gentlj^ undulating' crest line of the moraine is quite striking. Eastward from the Ford County reentrant to western Indiana. Tlie SCCtion Ot the BloOUl- ington morainic system east from the reentrant angle presents a series of ridges grouped in two belts. The outer belt throughout its course in southern Ford and northeastern Chamj^aign counties consists of a single broad ridg-e with billowy surface, having oscillations of 20 to 30 feet. As a rule, a well-defined crest is developed, but in places it completely disappears and the belt consists entirely of knolls and winding ridges, among which sags and shallow basins occur. Upon entering Vermilion County the outer belt soon disj)la3^s a double-crest line, and in the eastern part of the county is separated into two ridges, as shown on the Dan\alle topographic sheet, between which there is a narrow j^lain tract a mile or more, in width that is drained by Stony Creek. This plain, however, is present for only a few miles, the ridges as a rule, being closely associated. The surface of the ridges varies from gently undulating to strongly billowy. The billows are seldom greater than 30 feet in height. The moraine varies 75 or 100 feet in altitude in Vermilion County, but the variation is not abrupt, a fluctuation of 50 or 75 feet usually occupying 2 miles or more. It rises very promptl}' on its south border, especially in the western part of the county. In Warren County, Indiana, this belt, or at least its inner part, curves around gradually to the northward and constitutes the divide between Vermilion River and Pine Creek. It is overridden in northern Warren County by a moraine of the late Wisconsin series, which has not obliterated it, but has simply dotted the surface with small knolls, the majority of which are less than 10 feet in height. The outer belt joins the inner in northern Warren County and the combined belt passes northeastward into Benton County, as indicated below. Between the outer and inner belts of the portion of the Bloomington morainic system east of the reentrant angle is a narrow plain with very smooth surface, there being scarcely a knoll or undulation so much as 10 256 THE ILLINOIS GLACIAL LOBE. feet in height. This plain sets in in southeastern Livingston County, within 5 or 6 miles of the extreme north end of the reentrant, and is continuous through Ford, Champaign, and Vermilion counties, Illinois, and western Wan'eu County, Indiana. Its greatest width is in Vermilion County, where it reaches a breadth of 7 or 8 miles, a portion of it extending into the northwest part of the area shown on the DauAalle sheet. Its breadth in Ford and Champaign counties is 2 to 5 miles. The inner belt of this morainic system presents two, and in places three, crests in eastern Ford County. One crest leads from the point of the reentrant southwai'd thi-ough Mehau, between two branches of the Ver- milion River, to the vicinity of Henderson, where it crosses the eastern branch just above its junction with the western, and leads southeastward through Paxton along the north border of the river into Vermilion County. Another crest appears about 3 miles south of Roberts and leads southeast- ward, parallel with the crest just mentioned, crossing the exti-eme southwest comer of Iroquois County and fading out east of Paxton. A third crest leads from the extreme north end of the reentrant near Chatsworth, in Liv- ingston County, in a course east of south, past Pope's Grove and Roberts, into southwestern Iroquois County near Loda, beyond which it is diffi- cult to trace. It is on the slope of the third ridge that the knob-and-basin topogi'aphy above mentioned is developed. None of the three crest ridges Avhieh this inner belt presents in Ford County and adjacent districts have strong expression. The outer one stands 30 to 50 feet above the plain tract outside (west) of it, but is not so prominent on its inner border. The other ridges rise only 20 to 30 feet above the border tracts. These crest ridges each have a breadth of half a mile or more. In a few places the outer crest can-ies knolls 20 or 30 feet in height. The outer crest is also more winding than the others, and has a border indented bv extensions of the plain which enter it a half mile or more. In Vermilion and Iro(|Uois counties, Illinois, and Benton Countv, Indi- ana, this inner belt has a well-detined crest which forms the divide between the Iroquois and Vermilion rivers and which stands 3 or 4 miles back from the inner border of the moraine. This crest and the inner slope are gently midulating, with swells 10 to 20 feet in height. There is a gradual north- ward descent of perhaps 20 feet per mile to the inner-border plain. The crest usually is similnr to tlic inner slope, but orcasionallA' is sharplv ridged, THE BLOOMINGTOK MORAmiC SYSTEM. 257 as in the south part of T. 23, Rs. 13 and 14 W., where it rises abruptly 30 feet or more above the bordering- portion of the moraine in a narrow belt a half mile or less in width. South from the crest just mentioned there is, in Vermilion and Warren counties, another ridg-e interrupted by occasional gaps. The ridge is continuous from the north fork of Vermilion River near Rossville eastward to its junction with the outer morainic belt at Pine Creek in northern Warren and southern Benton counties. West from Ross- ville it can be traced in a curving course southwestward to the Middle Vermilion, near Potomac, and thence northwestward up the north side of that stream. It is interrupted by a gap a mile or more in width immedi- ately north of Potomac, and is deeply indented by valley-like sloughs at points farther east. In the vicinity of Blue Grass, in western Vermilion County, there is a plain occupying several square miles which separates this ridge from the one north of it. There is also a plain between the two ridges from the bend of Vermilion River south of Hoopstown eastward into Indiana as far as the ridges are traceable. The plain is scarcely 2 miles in width in the Illinois portion, but reaches a width of 3 or 4 miles in Indiana. The south ridge of this inner belt has usually a relief of about 50 feet above the plain on the south, and slightly less above the plane tracts lying between it and the north ridge. It is 2 or 3 miles in width, and its crest lies nearer the south than the north border. Its topographj^ is similar to that of the north lidge, there being a gently undulating surface with few knolls more than 20 feet in height. The portion covered by late Wisconsin drift. Tllis mOraiuic SyStOm is COUSpicUOUS for 15 or 20 miles within the limits of the late Wisconsin drift, and, as noted above, probably embraces the belt of thick drift which leads eastward through central Indiana into Ohio. The north ridge maintains its usual strength to the vicinity of Fowler, Indiana, where it terminates abruptly in a marshy tract. The remainder of the belt swings around the eastern end of the north ridge and dies out in a gently undulating tract 2 or 3 miles east of Fowler. It is a question whether the ridges in Benton County have suffered much reduction by the late Wisconsin ice invasion. That invasion formed onl}^ weak moraines in this district, consisting usually of belts of low knolls only 5 or 10 feet in height, which are accompanied by a gi'eat number of MON xxxviii 17 258 THE ILLINOIS GLACIAL LOBE. bowlders, whose distribution in belts was long since noted by members of tlie Indiana survey. These belts of knolls and bowlders cross the ridg-es and intervening plains of the Bloomington system nearly at right angles in a NNW.-SSE. course, as may be seen by reference to the glacial map (PI. VI). They assume greater strength a few miles to the north, there being a prominent morainic belt in' northwestern Benton and eastern Iroquois counties, near the border of Illinois and Indiana. In this connec- tion it may be remarked that the outer moraine of the late Wisconsin system is very variable in strength from place to place, and has a develop- ment about as weak in its passage across the Bloomington morainic system as in any pai't of its course. The weak moraine in eastern Iroquois County, Illinois. Of tllC WCak mOraiuCS COnUCCtcd with the Bloomington system the first to receive consideration is the one which emerges from beneath the late Wisconsin series near the Illinois- Indiana line and passes westward into Iroquois County. This is main- tained as a distinct ridge, 20 to 40 feet in height and scarcely more than a mile in width, for a distance of about 8 miles west from the State line, where it dies a,waj on the border of Sugar Creek. It has a gently undu- lating surface, the swells seldom exceeding 10 feet in height. The probable continuation of this ridge is found in a poorly defined, undulatory belt which appears on the west side of Sugar Creek opposite the end of this ridge and leads westward to Onarga. It stands scarcely 20 feet above the bordering plains on either side and its surface is but little more undulatory than that of the 2)lains. Its slight relief, however, is a matter of considerable conse- quence, since it stands too high for flowing wells to be obtained, while the neighboring plains furnish a large number of flowing wells from the drift. This belt does not connect definitely with the bulky ridges at the west, but as it is separated from them by a space of onlj^ 3 or 4 miles it seems to fall naturally into the same system. cropsey Ridge. — Froui tho wcst sidc of the reentrant angle in southeastern Livingston County a small ridge leads westward, as already noted, past Cropsey, across northern McLean County, forming a divide between the Mackinaw and Illinois- Vermilion drainage basins. The portion east from Cropsey stands 30 to 50 fiict above tlie plain on the south, and in places presents a very abrupt relief on that border. Toward the north it has a THE BLOOMINGTOK MOEAINIG SYSTEM. 259 more gradual descent to a plain wliicli continues descending to the Vermilion River. This eastern portion of the ridge has numerous small knolls 10 to 20 feet in height and occasional shallow basins. From Cropsey westward the expression is somewhat weaker, though a relief of fully 30 feet is main- tained as far west as the Chicago and Alton Railroad north of Lexington. There is also sufficient undulation of the surface to give this belt decided contrast to the plains on its border, swells 10 to 20 feet in height being quite common. West from the railroad the belt is definitely ridged for a few miles, but near Elpaso it becomes so obscure that further tracing and coixelation has not been attempted. There are many places toward the north and west, in northeastern Woodford, eastern Marshall, southwestern Lasalle, and east- ern Putnam counties, where, for a space of a square mile or more, the surface is quite as undulatory as in this morainic belt. It is possible that more detailed study will bring out a connection between these several undulatory tracts by which they may be thrown into a single belt. Possibly the divide between Vermilion River and tributaries of the Illinois flowing directly westward will prove to be the axis of such a belt. This divide, wherever it has been crossed by the writer, presents a slightly undulatory surface. The majority of the strongly undulatory belts, however, are found a short distance west of this divide. The surface is generally more undulatory west from the divide than east from it. chatsworth-cayuga Ridge. — From tlic reentrant angle at Chatsworth in south- eastern Livingston County northwestward nearly to Forrest the inner of the two weak members of this morainic system has sharp knolls inclosing basins, but their height is less than in the reentrant angle, seldom exceeding 25 feet. They occur on the slope as well as on the crest of the moraine. From the vicinity of Forrest northwestward for a few miles the moraine has a well- defined crest and is characterized by gentle swells 10 to 20 feet high. In sec. 34, Pleasant Ridge Township (T. 27, R. 7 E.), the single crest gives place to a double one, and two ridges are maintained from this point north- westward to the north branch of the Illinois-Vermilion River, the outer ridge coming to that river in sec. 14, T. 27, R. 6 E., while the inner comes to it in sees. 7 and 8, T. 27, R. 7 E. The outer ridge has a billowy crest, consisting of a series of slightly elliptical knolls, 25 to 40 feet high, 40 to 50 rods long, and about one-half as wide. These constitute an almost complete 260 THE ILLINOIS GLACIAL LOBE, chain leading from the river to the point of junction with the ijuer ridge. The inner ridge has not sucli a crest but, instead, a gentle swell-and-sag topography, with undulations of 20 to 25 feet. At the east branch of the Illinois- Vermilion River this morainic belt is interrupted by a plain nearly 2 miles in width. The ridges are, however, both present north of the river. The outer one appears in sees. 33 and 34, Owego Township, and bears slightly west of north to Cayuga. The inner appears in sec. 31, Saunemin Township, and bears northward about 2 miles, and is interrupted by a gap through which Felkey Creek has its passage. It appears on the west side of this creek and bears northwestward, joining the outer one near Cayuga. Each of these ridges has a gently undulating sm-face, but upon becoming coalesced a sharply undulatory topography sets in, in which the swells stand 30 to 40 feet above the bordering sags and sloughs. From Cayuga northwestward to northern Li^angston County the moraine under discussion is so closely associated on the inner border with the Marseilles moraine as to be obscured by it, and is interrupted by sev- eral gaps where creeks tributary to the Illinois- Vermilion River traverse it. These gaps occur at the following sti'eams: Wolf Creek, Deer Creek, Baker's Run, Mud Creek, and Blackstone Creek. The gaps are a mile or less in. width, while the ridges which lie between them occupy a length of 2 or 3 miles. These inteiTupted ridges consist of a series of billows ranging in height from 10 feet up to 40 feet or more. The most prominent one noted is in sec. 18, T. 30, R. 5 E., and is known as "Smith's Mound." It occupies about 40 acres and stands nearly 50 feet above the surrounding countrj'. Basins occur on its summit. Farm Ridge or Grand Ridge. — In soutliem Lasallc Couuty, just east of Sti'eator, as noted abo%'e, a morainic ridge known as Farm Ridge and also as Grand Ridge emerges from the outer border of the Marseilles moraine. It appears to be the continuation of the Chatsworth-Cayugsi Ridge. For a few miles, to Otter Creek Valley, it is sepai-ated from the Mai-seilles moraine by a naiTOw valley-like plain scarcely a mile in ^^'idth. In sees. 29 and 30, T. 31, R. 4 E., it carries sharp knolls, but the remainder of the ridge in the interval between tlie county line and Otter Creek has a gently undu- lating surface. At Otter Creek there is a break a mile or so in width. THE BLOOMINGTON MOEAIFIO SYSTEM. 261 Nortli of the creek the moraine consists of a series of knolls and sharp ridges standing- 20 to 60 feet above bordering valleys or depressions. In the southeast part of T. 32, R. 4 E., the moraine swings abruptly -westward, passing through the village of Grand Ridge to Farm Ridge post- office. It carries knolls which rise to a height of 20 feet or more. Between Grand Ridge and Farm Ridge the topography is of a subdued knob-and- basin type. From Farm Ridge to the Illinois bluff near Utica there is a smooth ridge with very gentle undulations, but with a well-defined relief of 20 or 30 feet. This ridge is in places capped by sandy knolls 10 to 15 feet in height, apparently wind drifted. The portion of this moraine north of the Illinois River consists of three disjointed ridg-es arranged end to end, but varying- greatly in the direction which they trend. They maj be traced readily on the Lasalle and Ottawa topographic sheets. The southern one has its southern termi- nus at the north bluff of the Illinois River between Little Vermilion River and Pecumsaugen Creek. It leads northward through" Lasalle Township for 2 miles or more, then curves slightly and turns east of north, passing through sees. 30, 19, 17, 9, and 4, Waltham Township. It then drops down rapidly just north of the township line. The second ridge appears within a mile northeast of its terminus, and bears slightly west of north for a distance of about 3 miles, when it also drops off suddenly near Tomahawk Creek. North of Tomahawk Creek a third ridge appears, which bears northward for about 2 miles, then bends toward the northeast and comes to Big Indian Creek about 2 miles below Earlville. No well-defined continu- ation was found on the north side of this creek, though there are occasional knolls along the divide between Big- Indian and Little Indian creeks, in both Lasalle and Dekalb counties, which may mark the line of its con- tinuation, and which would connect it with the main portion of this morainic system east of Shabbona. The ridges whose courses have just been out- lined have, as a rule, a sharp crest as well as swells and sags. The southern one is spoken of by the residents as the "Backbone," since it is quite sharp, standing in places 60 to 80 feet above the border districts, and being scarcely a mile in width. The ridge north of it has a height of 60 to 75 feet above the bordering plain, while the northernmost ridge has a height of 30 to 50 feet, except near its northern terminus, where it drops down to a height of but 15 or 20 feet. 262 THE ILLINOIS GLACIAL LOBE. THICKNESS OF THE DRIFT. The tliickness of tlie drift in the Bloomington morainic system is prob- abl}^ about equal to the measure of the relief above the outer-border district, which has a maximum of nearly 200 feet and which averages 75 to 100 feet along the ridges. The thickness is 50 feet or less between the rido-es and on plane tracts north and east of them. Small valleys had been formed in the Shelbyville sheet prior to the Bloomington invasion, and these valleys were filled with the drift of the Bloomington morainic system. They appear, however, to have been usually but 30 to 50 feet or less in in depth, so that the thickness of the Bloomington sheet is not greatly increased at these lines. The di-ift extends to some depth below the base of the Bloomington drift sheet. It is found that the earlier sheets of the Wisconsin series are present in considerable strength, as well as the lUinoian drift. The lowan drift is present in northern Illinois, but its border, as already noted, passes under the Wisconsin in Bureau County. It is not known to be present beneath the Bloomington system south from Bureau County, unless it be on the inner border of the system in Iroquois and neighboring counties. This matter is discussed above in connection with the lowan drift sheet. In determining the lower limits of the Wisconsin drift, two conspicuous lines of evidence are drawn upon. One is an abrupt change in the texture of the drift, the Wisconsin di'ift being fresh and soft, while the underlying sheets are harder and more aged in appearance. The other is the occur- rence of a black soil, beds of peat, or other decisive evidence of atmospheric action, produced at the surface of the lower or buried sheet of drift prior to the deposition of the later drift. In the portion of the Wisconsin drift lying outside the hmits of the lowan it is often an easy matter to decide upon the line of contact between the Wisconsin and the lUinoiau by the change in texture alone. It is so marked that the majority of well drillers have recoo-nized the two sheets even where no soil or peat has been preserved at their junction. Where the two lines of evidence are combined, it becomes an easy matter to decide upon the line of contact. It is not so easy a matter to decide upon the limits of the Wisconsin drift where it is underlain by the lowan, for the contrast in texture is not so great as between the Wiscorisin and Illinoian, though the lowan is seldom so fresh in appearance THE BLOOMIIs^GTON MORAINIO SYSTEM. 263 as the Wisconsin, even where deeply buried beneath it. There are numerous instances of the occurrence of buried soils in the portion of Illinois occupied by both the lowan and the Wisconsin drift, and there is little doubt that such soils occur below each drift, but seldom are two soils found in the same exposure or well section. In a few cases the soils are referred with confidence to the jimction of the Wisconsin and lowan, but in the majority of cases they appear to be at the junction of the lowan and Illinoian. An inspection of the well records presented below will serve to make clear the difficulties of interpretation. These well records indicate that buried soils differ greatly in elevation within short distances in the portion of Illinois covered both by the lowan and by the Wisconsin di'ift. This difference in elevation may be due either to the presence of two soil horizons or to an erosion of a buried drift sheet. In the latter case the lower soil would have been formed in a valley, while the higher would have been formed on the uplands. Were full records of wells preserved, it might be possible to interpret such cases satisfactorily. But usually the imperfections of the records are such that interpretations can scarcely be made. It is therefore only in the portion of the Wisconsin drift lying outside the lowan that the lower limits of the Wisconsin are clearly recognized. It is highly probable that the Peorian and the Sanga- mon soil are each represented. A brief statement setting forth the varia- tions in elevation of the buried soils in each of the counties occupied by the Bloomington morainic system will serve to make more clear the methods of interpretation as well as the difficulties of correlation in portions of the district. In Kane County buried soils appear beneath a plain southeast of Bur- lington at a depth of only 40 or 50 feet and at an elevation of about 850 feet above tide. The soil is here referred with some confidence to the Peorian interglacial stage at the base of the Wisconsin drift. On the elevated moraine southeast from this plain a soil is found at a depth of 180 to 200 feet and at an elevation of only 750 feet. It has been found in several wells in the west pai-t of T. 40, R. 7 E. This lower elevation is probably due to its being a lower soil horizon, presumably the Sangamon soil, at the junction of the lowan and Illinoian sheets, though the instances reported may chance to be in every case in the line of valleys cut in the lowan. The wide distribution, however, favors the interpretation that there 264 THE ILLINOIS GLACIAL LOBE. was a plain at about this level prior to the lowan invasion. In the neigh- boring township on the south buried soils are reported in sees. 14, 15, and 20, at 675, 710, and 720 feet above tide, which are probably Sangamon. In the villaffe of Elbum a biu-ied soil occurs at 790 feet above tide, which is perhaps Peorian. In Dekalb County only a few instances of. buried soil were collected. These are nearly uniform in elevation at slightly less than 800 feet above tide and are slightly lower than the plain outside the Wisconsin drift. It seems probable that they should be referred to the Sangamon soil, at the junction of the lowan and Illinoian. A buried soil is found beneath the lowan di-ift, outside the limits of the Wisconsin, in the A-icinity of Deer- field, at about the same elevation. In southeastern Lee County soils occur at a level lower than the plain outside the Wisconsin drift, tlu-ee instances being found where the elevation is 720 to 740 feet, while the plain is about 800 feet above tide. These seem referable to the Sangamon stage. One instance was found in sec. 34, T. 39, R. 2 E , of the occiu-rence of a buried soil at about the elevation of the outer-border plain; this may be referable to the Peorian. In northwestern Lasalle County there are many instances of the occur- rence of soil at 600 to 650 feet. This low elevation would suggest its reference to the junction of the lowan and Illinoian rather than the base of the Wisconsin. This soil horizon is well preserved in eastern Bureau County. It seems to be quite uniform in elevation over several townships in which the smface of the Wisconsin has a variation of more than 100 feet in altitude. In the counties south from Bureau County the lowan di-ift has not been recognized, and possiblj' it does not reach these counties. No records were obtained which show buried soil either in Putnam or in Marshall County. In Woodford County wells in the vicinity of Metamora pass tlu'ough a soil and enter a hard till at about 140 feet, or at an elevation of 680 feet above tide. A coal shaft at I\Iinonk, in the eastern part of the county, passes from soft till into hard till at about the same elevation, though the depth of soft till there is only 62 feet. It is probable that in both of these instances the soil is referable to the Sangamon. In northern Tazewell County exposm-es were found, both in the Illinois blufi" and along Farm Creek, where the loess occurs beneath the Wisconsin drift at an THE BLOOMINGTON MOEAINIO SYSTEM. 265 elevation of about 625 feet. In these exposures the Peorian and Sangamon both occur as noted above. Instances of buried soil at an elevation of 625 to 650 feet are r^Dorted from the vicinity of Cooper, which are probabl)^ Sangamon. The Wisconsin drift ranges in thickness from 50 feet up to fully 150 feet in this portion of Tazewell County. In northwestern McLean County instances of a bixried soil and a change from soft to hard till are found at a depth of 150 feet beneath the crests of morainic ridg'es and at an elevation of 650 feet above tide. There are instances of "black clay" at lower levels, which may prove to be soil hori- zons. In the southwestern part of the county, in sec. 29, T. 24, R. 1 W., and sec. 3, T. 23, R. 1 W. (which are situated south of the Bloomington moraine), the fresh till extends to a much lower elevation than in neighbor- ing districts. It seems probable, therefore, that there was a valley or con- cealed lowland tract traversing these sections. In sec. 3 a black muck was found below the fresh till at a depth of 200 feet and at an elevation of but 625 feet above tide. In the vicinity of Bloomington a black soil is found at an elevation of 625 to 640 feet above tide, which probably is of Sangamon age. Another buried soil occurs near the base of the drift at an elevation of about 540 feet. This is beneath a hard till and is perhaps preglacial. North- eastward from Bloomington the elevation of the surface of tlae Illinoian drift sheet is found to soon reach 700 feet; at least wells in T. 24, R. 4 E. enter a hard till at that elevation. One well in sec. 4 of this township is reported to have entered hard till at an elevation of 750 feet above tide. South from this township, in the vicinity of Leroy, a buried soil is found at an elevation of 740 feet above tide, which is probably under the Shelbyville or lowest Wisconsin drift sheet. Eastward the elevation of the surface of the Illinoian drift appears to decline to 700 feet or less, as shown by wells in southern Livingston, southwestern Ford, and western Champaign counties. The elevation continues decreasing toward the north and east across northern Ford, Iroquois, and Vermilion counties. The elevation of the Illinoian surface throughout much of Ii-oquois County and northern Vermilion County is 600 feet or less. In Iroquois County, as noted above, there are two soil horizons, one being at the junction of the fresh and soft till with the harder till, the other being in the midst of the hard till. There is little doubt that the upper soil marks the base of the Wisconsin. But whether the sheet of drift which it 266 THE ILLINOIS GLACIAL LOBE. caps is lowan or Illinoian lias not been determined. Upon this determina- tion must rest the age of the lower soil horizon. Buried soils are exceptionally well preserved along much of the course of the Bloomington system east from the Illinois River, instances of their occiiiTence in well sections being much more numerous than in districts to the north, except limited areas in Bureau, Lasalle, Kane, and McHenry counties. There is scarcely a township in which the junction of the "Wis- consin drift with older sheets may not be satisfactorily ascertained, either through the presence of the buried soils or by a change in the till. STRUOTUKE OF THE DRIFT. Throughout the entire length of the Bloomington system the great mass of the drift composing its moraines, and also the plains between them and on their inner borders, together with earlier sheets of the Wisconsin series, consists of a soft blue till moderately stony and strikingly in contrast with the harder till found beneath it. The till is very adhesive, so that when excavated by a well auger it may be unrolled in great masses. The under- lying harder till is far less adhesive. The surface portion of this till sheet is oxidized to a depth of 6 to 10 feet and has a brownish color. There are occasional developments of a pink-colored till. In places the pink color extends to gi'eat depth, but usually the blue color sets in within a few feet of the surface. The pink color is especially noticeable in the western and northern part of the morainic system, from Peoria County northward. Yellow till is also reported to occur in the midst of the blue till at many points. It apparently marks the surface of earlier sheets of the Wisconsin series. Its occurrence is known by well recoi'ds only, no natural exposures having been found. Its degree of leaching and its state of oxidation are not known. Associated with the till at various depths there are beds of sand and gravel, often of considerable extent, which afford a supply of water for many wells. It is not usual, however, to obtain strong wells witliin this drift sheet. In every county hundreds of wells have been sunk to lower horizons because of the inadequate supply found in this sheet of drift. There are very few gravel knolls in the moraines of this system, though it is found that many knolls contain gravelly pockets in the till and these have been utilized to some extent for road ballast. The amount of avail- THE BLOOMINGTON MOEAINIC SYSTEM. 267 able gravel, however, seems to be scarcely adequate to supply ballast for the wagon roads of the region traversed by the moraine. The composite belt with which this morainic system connects at the northeast is much better supplied with surface gravel. As noted above, the outer face of the moraine in Lee and northern Bureau counties is heavily coated with sand, which apparently has been drifted by the wind from the Green River Basin on the west. From this sand belt southward through central Bureau County the surface of the outer ridge is in j)laces coated with sand or a sandy loam. The texture of the moraine itself is also exceptionally sandy in that portion of the belt. Sand is found in the form of dunes along the east bluff of the Illinois River, from the bend of the river at Hennepin southward to the inner border of this morainic system. Sand deposits were also noted on the inner slope of the moraine in northern Vermilion County and west from the reentrant angle in southeastern Livingston County. It is probable that the sand deposits in both these localities are attributable to the presence of temporary glacial lakes held in front of the retreating- ice sheet, whose waves worked upon the surface of the till sheet and formed the sandy beds there present. As noted below, sand in places assumes the cliaracteristic features of beaches or shore lines in portions of the plains noi'th of this morainic system. The surface of this morainic system from the vicinity of Bloomington northward to Dekalb County is generally coated with a loess-like loam or silt to a depth of 2 to 4 feet. East from Bloomington this surface silt is so thin as scarcely to conceal surface bowlders. The silt also extends over the plain east of this morainic system in counties bordering the Illinois River, and has often a depth of 6 or 8 feet on these plains. It is especially prominent on the plain between the outer and inner belts in the Bureau Creek Basin, its average thickness being not less than 6 feet. From the inner belt eastward, in Bureau and Lasalle counties, it is less conspicuous than in the Bureau Creek Basin, being scarcely 2 feet in average thickness. This surface silt was apparently deposited within a short time after the retreat of the ice sheet, for the underlying till sheet appears to have suffered no leaching prior to its deposition. The origin and mode of deposition of this silt or loess-like loam, like that on adjacent portions of the Shelbyville sheet, are as yet not clearly inaderstood. The loess-covered plains on the west seem to afford a source of supply, and the prevailing winds, if in the 268 THE ILLINOIS GLACIAL LOBE. same direction as now, would have earned miicli atmospheric dust from them eastward. Tt is quite probable that some of the material was derived from this source, though perhaps only a minor part. It is found that this loess loam, when reaching a depth of 4 to 6 feet or more, is usually highly calcareous in its lower portion, while the loess of the outer-border districts is thoroughly leached to a depth of several feet. In all probability it had suffered considerable leaching before the ice sheet withdrew from the Bloomington morainic system. It is to be expected, therefore, that a non- calcareous or leached deposit would be made by transportation of dust from these plains. ' The presence of the calcareous material in the silt which caps the western border of the -Blooixdngton till sheet seems to make it necessary to call in the action of glacial waters charged with fresh cal- careous silt. The manner in which the silt was distributed is an unsettled question and one on which further light seems necessary. It will probably be found in a combination of aqueous and seolian agencies. As shown below, the drainage conditions on the outer border of the Bloomington system were favorable for the transportation of gravel by streams issuing from the ice margin. There would appear, therefore, to have been a rapid descent for these streams to the region south and west from the ice sheet. Such being the case, we can scarcely infer that the loess which covers the elevated parts of the morainic system was deposited by a sheet of water, for this would imply a general submergence. It is suggested that there may have been portions of the border district in which the waters found inadequate di'ainag'e. In such places silts may have been spread out which were afterwards transported by wind to the moraine. The matter, however, is one of conjecture rather than of demonstration. Surface bowlders are numerous only at a few points on this morainic system, being rarely met where no sand or silt deposits are present to conceal them. But in this respect the Bloomington system is not different from other moraines of the early Wisconsin series. In Kane, Dekalb, and Ogle counties there are occasional bowlders along the crests of the ridges, but they seldom become conspicuous. On the plane tracts in these counties they are quite rare, but this is not a fair field for study because there is us-ually a sufficient amount of silt to conceal them. Bowlders abound along the outer face of the outer belt for a few miles in south- eastern Lee County and on the crest and outer face at a few i)oints in THE BLOOMINGTON MOEAINIC SYSTEM. 269 Bureau, Marshall, and Peoria counties, there being some farms on which they are a serious hindrance to the cultivation of the soil. But much of the moraine in these counties is silt or sand covered to a depth of several feet, so that bowlders, if j)resent, are concealed. In the portion of the morainic system between the Illinois River and Bloomington scarcely any surface bowlders were noted, though there the surface silts are several feet in depth. From Bloomington eastward there is generally a sufficient number of bowlders at surface or at slight depth in the soil to meet demands for some time to come in supplying foundations for buildings. In places they were so numerous that farmers have collected them in piles in the fields. Such is the case in the northern tier of townships of Vermil- ion County, both along the crest of the north ridge and on its inner slope. The bowlders range in size from 8 or 10 feet in diameter downward, the ordinary size being 2 to 4 feet. Granite bowlders predominate over other classes of rock along nearly the entire belt, and a few limestones were noted. Greenstones and quartzites are also common. The bowlders are in some cases much rounded by exfoliation, a feature which seems more conspicuous than in bowlders on the Shelbyville sheet. Numerous com- parisons were made of bowlders embedded in the till with those found at the surface, and in almost every instance it was found that local or semi- local rocks are much more abundant in the till than among the surface bowlders. A much larger proportion of striated stones is also found in the till than at the sm-face ; indeed, the surface bowlders are seldom striated. These are features which, as already noted, are generally characteristic of the till of the entire region under discussion in each of the several sheets represented. Occasionally very large limestone blocks are foinid at the surface or but shghtly embedded in the drift. One block found a short distance northwest of Rossville, in Vermilion County, furnished several wagon loads of excellent building stone, and when first discovered was thought to be a ledge in situ, but subsequently proved to be a bowlder embedded in the till. In that vicinity the drift is about 200 feet in depth and is underlain by the Coal Measures. The nearest known outcrop of limestone is about 30 miles to the north. Numerous well sections collected along the line of this morainic system are presented in the discussion of the wells in the latter part of this report, and these will serve to illustrate the variations in structure which this morainic system presents. 270 THE ILLINOIS GLACIAL LOBE. CHARACTER OF THE OUTWASH. The writer's examination of the features on the outer border of the Bloomington morainic system covers the portion from Bloomington north- ward, and the discussion pertains chiefly to that portion. The portion east- ward from Bloomington was examined some years since by Prof. R. D. Sahsbm-}', but has received scarcely any attention from the writer. It will be obser-^-ed that the Bloomington morainic system forms the source of several streams whose courses are southward or westward from it through the outer-border district. It also forms the source of other streams which lead northward or eastward or southeastward through the inner- border district. Still other streams flow through this morainic system from the inner into the outer border district. Of the first class the several head- water forks of Wabash- Vermilion River, Sangamon River, Salt Creek, the two Kickapoo creeks. Sugar Creek, Green River, and the two forks of Kish- waukee River are worthy of mention. Of the second class, Iroquois River, the Illinois-Vermilion RiA'er, Bureau Creek, and the western tributaries of Fox River are illustrations. Of the third class the Illinois and Mackinaw rivers are the only examples in Illinois. An examination of these valleys brings to light important contrasts. The streams which flow away from the outer border of the moraine are in most instances found to occupy valleys which had been excavated somewhat by streams which antedated the formation of this moraine. These valleys received the outwash from the moraine and were partially filled by it. The streams on the inner border of the moraine had not the advantage of previously formed valleys, and in consequence their channels are entirely the result of stream action since the withdrawal of the ice sheet from this morainic system. It is found that the valleys which lead away from the moraine through the outer-border district have in most instances a filling of gravel or sand which is definitely connected with the morainic system as an outwash from the ice sheet. The streams which lead from the moraine across the innei'-border district are not thus characterized by sand-and- gravel filling. In some cases the streams issuing from the edge of the ice sheet had sufiicient force to transpoi't gravel for many nnles away from the ice border. In other instances they were able to carry the gravel but a few miles, as shown in the discussion below. The extent of the gravelly and THE BLOOMINGTOiSr MORAimO SYSTEM. 271 sandy outwasli along- the borders of the Bloomington morainic system is outhned in the glacial map, PI. VI, where it may be compared with that of other morainic systems. This comparison shows that the outwash was fully as extensive as in any substage of the early or late Wisconsin. It is, how- ever, of a finer grade than in some of the later snbstages, a feature which seems to indicate that the attitude of the land may have been scarcely so favorable for vigorous di-ainage as in the later substages. In the following detailed discussion the valleys in the vicinity of Bloomington are first con- sidered. From this point the valleys are taken up in order toward the west and north, along the outer border of the morainic system. For a few miles southeast from the meridian of Bloomington there is a shallow, valley-like depression along the outer border of the moraine. It is about a half mile in width, and its surface stands 15 to 25 feet below the plain on the south and 75 or 100 feet below the crest of the moraine on the north. Its eastern end is near the village of Downs, at Kickapoo Creek. It leads westward across the interval between East and West Kickapoo creeks, and also across that between West Kickapoo Creek and an eastern tributary of Sugar Creek. Both branches of Kickapoo Creek pass directly across it, but the branch of Sugar Creek referred to follows the depression westward for a distance of 2 miles, and there turns away from the moraine. The depression is found to have a filling of fine gravel and sand of con- siderable depth, so that wells 10 or 20 feet deep do not reach its bottom. The gravel was carried from this valley-like depression for some distance down each of the valleys which lead away from it, and is preserved in the form of terraces which stand 20 or 30 feet below the level of the bordering plains and about 20 feet above the present stream bed. The gravel prob- ably extends down at least to the level of the present streams. It would appear, therefore, that valleys had been excavated to, if not beyond, their present depth prior to this filling. The gravel filling was traced down Kickapoo Creek beyond Hey worth, a distance of about 10 miles fi'om the outer border of the moraine. Just north of Heyworth it is preserved in a broad terrace which has been extensively opened for gravel by the Illinois Central Railway. How much farther down the valley the gravel was transported has not been determined. On the tributary of Sugar Creek which leads away from the western end of this depression the gravel deposits were followed continuously down to a point east of Shirley. They 272 THE ILLINOIS GLACIAL LOBE. were also noted at Funk's Grrove and at points below. The gravel was apparently transported to the junction of this fork with a more western tributary. In each of these valleys the gravel is of medium coarseness and carries a moderate admixture of sand. The presence of the sand is thought to indicate that the current was not vigorous, though it may have been somewhat stronger than that of the present stream, for the latter finds it difficult to transport the coarser portions of the material even at flood stages. As these valleys are narrow, averaging scarcely more than one- fourth mile and seldom reaching one-half mile in width, the glacial streams which occupied them can not have had very great volume. The depression on the outer border of the moraine does not seem to fit in naturally as a part of the drainag-e which preceded the formation of the morainic system. As yet, no satisfactor}^ explanation of its mode of formation has been found. Possibly it was formed in connection, with the ice invasion, either by the ice or by waters issuing from it. It bears some resemblance to "The Fosse" on Nantucket Island described recently by Curtis and Woodworth in the Journal of Greology, though it has not a sand plain or overwash apron on its south border.^ On the branch of Sugar Creek which leads through the west part of Bloomington there is a belt of gravel 60 to 120 rods in width, which extends up the valley at least to the Bloomington waterworks in sec. 32, Normal Township, just outside the inner large ridge of the Bloomington morainic system. At its head it is merged with the flood plain of the creek, but from Bloomington southw:ard it stands a few feet above the flood plain. The depth of gravel at the waterworks is about 30 feet, and it appears to maintain this depth for some distance below Bloomington. There is usually a yellow-brown silt 4 to 6 feet in depth capping the gravel. The gravel contains a large amount of fine material, so that sand is screened from it for plasterers' use. Large pebbles are rare, though' it contains a few 5 or 6 inches in diameter. This branch of Sugar Creek reaches the outer border of the Bloomington morainic system about 5 miles below the waterworks. The gravel here spreads westward beyond the limits of the valley, covering the lower portions of the plain between this branch of Sugar Creek and one that leaves the moraine 4 miles to the west. Low till swells lise above 'Nantucket a morainal island: By 6. C. Curtis and J. B, Woodworth, Jour. Geol., Vol. VII, 1899, pp. 226-236, PI. I, Figs. 1-5. THE BLOOMINGTON MORAINIC SYSTEM. 273 the level of the gravel surface, showing- that the deposit is thin. The western tributary also has gravelly deposits above tlie point of its emergence from the moraine, but these were not traced to their head. The distance to which the gravel deposits have been carried down the two branches of . Sugar Creek beyond the border of the moraine is not ascertained, but it is known to be at least 10 miles. Mackinaw River has its source on the inner border of the main ridges of the Bloomington system, but Cropsey Ridge, one of the weaker mem- bers of the system, lies north of the headwater poi'tion of the stream. Gravelly deposits have been noted at a few points on the borders of the headwater portion. They have not, however, been traced into definite connection with Cropsey Ridge. There is not a continuous belt of gi-avel leading down the valley from this headwater portion. A section several miles in length was examined just below the crossing of the Lake Erie and Westei'n Railway, in which no gravel filling appears to have been made. That portion of the valley was found to contain deposits of silt of considerable thickness which reach a level 20 or 30 feet above the present stream. Upon continuing down the valley to the inner border of the outer morainic ridge a gravel terrace is found to set in abruptly at an altitude about 50 feet above the stream. This terrace merges into low gravelly knolls at its head and on its border, and thus makes a definite con- nection with the moraine. As it stands somewhat higher than the silt-filled portion of the valley just above its head, there was probably a pool in that portion of the valley prior to the excavation of the gravel which forms the moraine-headed terrace, and the silt deposits just noted were probably laid down in this pool. Mackinaw Valley appears to have been excavated nearly to the level of the present stream prior to the formation of the Bloomington system and to have had a width of nearly a mile. The terrace has been traced down the valley continuously from the moraine to. the point where the Mackinaw enters the Illinois Valley in the eastern part of Sand Prairie Township, a distance by direct line of about 17 miles from the outer border of the moraine. The altitude of the ten-ace decreases about 100 feet in this dis- tance, being 640 feet at the outer border of the moraine and 650 feet at the point where it joins the Illinois Valley. The stream falls 83 feet in the MON XXXVIII 18 274 THE ILLINOIS GLACIAL LOBE. same distance (from 573 to 490 feet), and the teiTace maintains a somewhat regular altitude above it, being about 65 or 70 feet above it at the outer border of the moraine and 50 feet at the border of the Illinois Valle}'. The terrace apparently has little fall in the 3 or 4 miles occupied in crossing the moraine. The remnants of the tex'race occupy nearly one-third of the width of the A^alley. Several good exposures of the gravel were found, and these quite uniformly show a coarse gravel and cobble near the surface of the terrace, with finer gravel below. The coarseness of the material is such as to indicate vigorous drainage, apparently stronger than that of the present stream. A small northern tributary of the Mackinaw, Deer Creek, emerges from the moraine a few miles north from the point where the Mackinaw leaves it. This also carries deposits of gravel along the borders of the valley. It is preserved in small remnants flanking the slopes up a height of 20 or 25 feet above the creek at the point where the stream leaves the moraine. The upland plain stands about 20 feet higher than the upper limits of the gravel. On Farm Creek, a tributary of the Illinois, entering opposite Peoria, there is a gravel deposit heading in the midst of the Bloomington system about 2 miles west of Washington. This has been traced continuously down to the Illinois River Valley, a distance of 8 miles. At its head it is nearly as low as the creek flood plain, being scarcely 10 feet above the stream, but its fall is far less rapid than that of the creek. The creek has a fall of about 180 feet in the 8 miles while the terrace falls scarcely 60 feet. At Farmdale the terrace stands about 85 feet above the creek and at East Peoria about 120 feet. The depth of the gravel on tliis terrace is usually only 15 or 20 feet, including a silt capping 3 or 4 feet in depth. The bi-eadth of the valley in which it is deposited was apparently one- eighth to one-fourth of a mile. The present stream has in places formed a valley of greater width, but usually it is confined to narrower limits than the old valley. The valley in which the gravel filling was made had been nowhere cut to a depth of more than 40 or 50 feet below the bordering plain outside the Bloomington moraine, and the gravel filling has reduced this depth to about 25 feet. The work performed, by the stream which preceded the gravel filling was tlierefore but a small fraction of the amount performed by Farm Creek since tluit filling. 5 Q _ O tr Li- O THE BLOOMIXGTOJS MOEAIMC SYSTEM. 275 On the Illinois River Valley there ai'e extensive gravel deposits forming- a broad terrace which occupies a gap in the Shelby ville moraine just below the outer border of the Bloomington moraine, a gap through which the river passes. The north part of the city of Peoria stands on this terrace and is commonly referred to as the bluff or upland portion, since it stands about 170 feet above the Illinois River. These deposits may prove to date from the Shelbyville substage of glaciation, though from their coarseness and general relations it seems more probable that they were connected with the Bloomington and represent the height of valley filling on the outer border of that morainic system. Their freshness cei'tainly places them in the Wisconsin series. The following reasons for referring them to the Bloomington rather than the Shelbyville substage may be mentioned: (1) The terrace corresponds closely in elevation with the gravel terrace on Farm Creek just described, which connects with the Bloomington morainic system east of the Illinois River; (2) the terrace on the Illinois occupies a shallow valley cut into the Shelbyville till sheet ; (3) the vigor of drainage corresponds to that of the Bloomington and is greater than seems elsewhere to characterize the Shelbyville substage of glaciation. A view in a gravel pit on this terrace appears in PL XIII. The gravel wherever exposed on this terrace is composed largely of limestone pebbles. The local sandstone and shale pebbles and the Canadian crystallines constitute only a small percentage of the coarse rock material. The sand and fine material found associated with the gravel are also calcareous. In places the gravel is cemented with lime. It is probable that the large percentage of limestone pebbles is due to the great number of such jjebbles in the till of the Wisconsin sheet in that vicinity. The highest well-defined terrace noted on the Illinois above Peoria, which seems referable to the Bloomington substage of glaciation, is found near the inner border of the moraine at and below the village of Chillicothe. It stands only 550 to 560 feet above tide, or 40 to 50 feet lower than the terrace on the outer border at Peoria. This difference is probably referable in part, if not entirely, to a reduction from the original height of valley filling, for a well-defined bank separates the top of the terrace from the portions of the moraine bordering it. The terrace in the vicinity of Chilli- cothe contains much coarser material than at points above or below. The extensive excavations for railway ballast reveal a mass of cobble and 276 THE ILLINOIS GLACIAL LOBE. bowlders 20 or 30 feet in depth. The excessive amount of coarse material seems referable to the contribution of such material from the overhanoino: ice during the building- up of the teiTace. For this reason the terrace has been connected with the Bloomington rather than a later substage. Possibly some cutting of the valley of the Illinois took place between the heavv deposition of gravel on the outer border and that near the inner border of the moraine, in which case the deposits near the inner border raaj not have been built up to the level of those on the outer border. This view seems supported by the observations farther up the valley, no remnants higher than that at Chillicothe ha^dng been found. Down the valle}^ from Peoria there is a rapid decrease in the altitude of the gravel terrace, a fall of 70 or 80 feet being made in the 10 miles to the mouth of the Mackinaw River, just below Pekin. There is a great expansion of the valley just below that city, in which the gravel has an elevation of 520 to 530 feet above tide, or 90 to 100 feet above the Illinois River. The gravel is capped by sandy deposits, which are in places drifted into dunes 20 to 30 feet or more in height. Gravel deposits are conspicuous down the val- ley beyond the mouth of the Sangamon River, but the material becomes finer in passing down the stream. The gi'avel has a height of about 500 feet above tide at the ro^outh of the Sangamon, or 75 to 80 feet above the level of the Illinois River. Farther down it gradually approaches the level of the river, tlie highest terraces near the mouth of the sti'eam, which seem connected with the Wisconsin invasion, being but 40 to 50 feet above low water. There appears to have been no gravel outwash into Kickapoo Creek Valley in northern Peoria County, although this stream follows the outer border of the moraine quite closely for a distance of 7 or 8 miles. Upon turning away from tlie moraine the creek cuts through the Shelb5'ville moraine, and it is proba]:)le that this offered an obstruction to the rapid escape of waters from the ice margin. In southeastern Stark County there is a low plain extending back from Spoon River Valley to the Bloomington moraine which received a slight outwash from the moraine. A few exposures were found where gravel to a depth of several feet was deposited. It seems, however, to have been only a weak point of discharge, as the gravel deposits scarcel3' extend to Spoon River Vnll('\-, tliougli this valley apjiroaches within 6 or 7 miles of the THE BLOOMINGTON^ MORAINIC SYSTEM. 277 moraine and receives two tributaries which head in the moraine. There are other tributaries of Spoon River farther north which also head in the moraine, but these seem to have afforded only weak lines of escape for glacial waters. The portion of the moraine bordering the Green River Basin in north- ern Biireau and southeastern Lee counties, as already noted, is coated heavily with sand on its outer face. The sand extends westward from the moraine down the Green River Valley, covering southeastern Whiteside and northern Henry counties and occupying the low tract between Green and Rock rivers. This sand is in all probability an outwash from the moraine, being too extensive a deposit to be referable to the action of lake waves. The sand apparently forms, over much of the district which it occupies, a coating 10 to 20 feet or more in depth. The depth is so great that natural exposures of underlying beds are rare and only a few wells reach its bottom. It is therefore difficult to ascertain whether there is much gravel outwash. Near the border of the moraine in northern Bureau County there are, however, a few exposures of gravel at the base of the sand which are thought to be an outwash from the moraine. The gravel appears to extend but a few miles west, for in the vicinity of the county line of Btireau and Hemy counties wells indicate that the sand rests upon a compact clay. At the head of the Green River Basin, in eastern Lee County, there is a gravel plain, covering about 25 square miles, whose eastern border is in the moraine. It extends back into the moraine a mile or more, along the east and south branches of Willow Creek, and there coimects with gravelly knolls which dot the valley slopes and bottoms for 2 or 3 miles farther east. This gravel plain extends northward along the west border of the moraine to the south branch of Kite River at Steward. At this stream also the g'ravel plain connects closely with gravelly knolls which extend some distance up the valley into the moraine. The gravel extends only a few miles away from the moraine, scarcely beyond the east border of Inlet Swamp. The waters issuing from the ice sheet probably had sufficient strength to carry the gravel down the rapid slope to Inlet Swamp, beyond which they could carry only sand. There is considerable fall in the Green River Basin, but it is irregularly distributed, so that di-ainage even now is very imperfect. 278 THE ILLINOIS GLACIAL LOBE. On the outer border of the moraine in eastern Ogle County there is a depression due to a preglacial valley which was not completely filled. Into this depression considerable sand and fine gravel was carried by the waters issuing- from this moraine. There were two lines of escape, the southern portion of the depression being drained westward through Kite River, while the northern portion was drained northward through Killbuck Creek. The sandy and gravelly deposits are thickest along the portion drained by Kill- buck Creek, where they have a depth of 20 feet or more. In the portion di-ained by Kite River the average depth is but 5 or 10 feet, and portions of the depressed area have scarcely any surface gravel. The deposits in this depressed tract would be classed as a gravelly sand rather than gravel, the proportion of coarse material being very small. The streams issuing from the moraine in Dekalb County (South Kishwaukee River and Owen's Creek) have only a small amount of gravel and sand outside the moraine, and appear not to have been lines of vigorous discharge. Sandy material borders Owen's Creek for about a mile each side the stream from the vicinity of South Grrove northward to the mouth. The material is full)^ as fine as that on Killbuck Creek. On the Kishwaukee the belt of sand and gravel is less definitely outlined, there being places where no sand or gravel is found on either side of the valley, while at other places it extends back southward from the valley to the moraine, a distance of a mile or more. It is probable that a portion of this sand and gravel is an outwash connected with the formation of the moraine, though it connects rather vaguely with the moraine. In northwestern Kane Coimty a plain of sandy gravel extends from the moraine westward to the valley of Coon Creek and leads thence down the valley to the north Kishwaukee. It there connects with belts of gravel which lead in from the east and north, all of which appear to be an out- wash from the western border of the composite belt of moraines in McHenry County. A broad belt of gravel leads down the north Kishwau- kee to its junction with the south branch near Cherry Valley. Below this point the valley is so narrow that gravel terraces are inconspicuous, though they continue to the Rock River Valley. The conditions of drainage attending the formations of the minor moraines is next considered. The character of the outwash frc^m tlie weak moraine in northern McLean Count v has received but little attention. THE BLOOMINGTON MORAmiC SYSTEM. 279 Gravel deposits of medium coai-seness have been observed at and above Lexington on the headwater portion of Mackinaw River near the outer border of the moraine They underHe the plain for only a short distance back from the river valley at these points. The extent of these deposits and their relation to the moraine have not been ascertained. It seems probable, however, that they are a g-lacial outwash. The latest of the moraines in the Bloomington system follows the east border of the Illinois- Vermilion River throughont much of its course, a position that under present conditions would afford fair escape for the glacial waters. But at the time the moraine was forming, the channel now occupied by Vermilion River had not been excavated. The broad basin which it traverses has scarcely 20 feet descent in the 40 miles from Pontiac to the borders of the Illinois River. The conditions were favorable for the ponding or accumulation of water issuing' from the ice sheet, as well as for water di'aining' into it from the land areas on the southern and western borders. A belt several miles in width might have thus become submerged and a lake-like river formed. Even though the volume of water were great, the force of the current would be weak until the channel had been cut back several miles into the basin. The opening of this channel has been very slow, for it is now but partly accomplished, the main part of the chan- neling being in the portion below Streator. Evidence of a ponding of waters in this basin is found in deposits of sand and silt which cover it. The sand deposits are most conspicuous in the sotithern portion of the basin, and are there drifted in places into low dunes and ridges. From Pontiac southward the deposits consist of silt or fine sand. The ponding of waters and deposition of sand and silt probably began with the with- di'awal of the ice sheet from the divide on the west border of the basin, and continued until the ice sheet no longer contributed its waters to the basin. This would involve not only the time when the moraine under dis- cussion was forming, but also that embraced in the production of the Mar- seilles moraine. Possibly the ponding continued to much later date, though in less volume than at the morainic substages As shown below (p. 290), there was a discharge into this basin from a small glacial lake held in the basin of the Iroquois River. This line of discharge followed the east fork of Vermilion River, which passes through the moraine under discussion, 8 to 10 miles southwest of Pontiac. The character of the outwash appears 280 THE ILLII^OIS GLACIAL LOBE. to have varied little during the long period in which the ice sheet dis- charged waters into this basin. For a few miles along the immediate bor- ders of the river below the point where the East Fork enters this basin a fine gravel occiirs, which was probably contributed by the outlet. There may have been less ponding of water at this time than when water was contributed by the ice sheet more directly to the basin. This subject is discussed more fully in connection with the glacial lake (pp. 290, 314, 336). No doubt the Illinois Valley received considerable material as an out- wash from this minor moraine, but as yet the deposits have not been sepa- rated from those made later, and nothing is known concerning the degree of coarseness of the material. The portion of the moraine north from the Illinois in central and northern Lasalle County seems to have been no better favored for escape of water than that along the border of the Illinois- Vermilion. The plain west of it carries thiu deposits of silt, but whether their deposition is largely referable to water issuing from this moraine is not known. Pos- sibly wind transportation was an important factor in the deposition. INTERMORAINIC TRACTS. EXTENT OR DISTRIBUTION. Under this topic are discussed the plains and gently undulating tracts among the ridges of the Bloomington system and a plain between the inner ridge of the Bloomington system and the Marseilles moraine. The inter- morainic tracts are of much greater extent than the morainic, for the latter are restricted to narrow belts. About 90 per cent of the area embraced between the inner border of the main ridges of the Bloomington system and the outer border of the Marseilles system is here classed as nonmorainic. This area of about 6,000 square miles ranges in width from 25 to about 50 miles, being widest in central Illinois. It has a length of about 175 miles between northern Kane County, Illinois, where it connects with the com- posite belt of moraines, and western Benton County, Indiana, where it is shut off by moraines of late Wisconsin age. GENERAL FEATURES. The portion north of the Illinois River, embracing southwestern Kane, southeastern Dekalb, northwestern Kendall, northwestern Lasalle, and THE BLOOMINGTON MOEAINIC SYSTEM. 281 eastern Bureau counties, shows a marked descent from northwest to south- east and a less marked descent from northeast to southwest. Its altitiide along" the border of the moraine declines from about 800 feet at the north- east to 700 feet at the southwest, or 100 feet in a distance of 50 miles. It declines an equal amount in scarcely 26 miles in passing from the border of the moraine southeastward to the bluff of Fox River. The altitude along the bluff of this river ranges from about 700 feet at the north to 620 feet at the south. Aside from the narrow morainic belt already discussed, which traverses this plain from Utica northward to Earlville, the surface is as a rule only slightly undulatory. There are, however, a few short eskers with associated chains of gravelly knolls — discussed below — and also scat- tering knolls 10 or 20 feet in height, all of which rise somewhat abruptly above bordering plains. South from the great bend of the Illinois River the features are more varied than in the district just touched upon. The narrow strip on the west of the Illinois Valley descends rapidly from the moraine to the river bluff. It has a gently undulating- surface, with a tendency to north-south ridging. East from the Illinois Valley there are nearly plane tracts inter- rupted by sm'all areas with undulatory surface, which in places bear strong resemblance to the morainic belts. These undulatory tracts are most abun- dant in a belt a few miles in width that leads southward from the bend of the Illinois through eastern Putnam, eastern Marshall, and east-central Wood- ford counties, its eastern edge being near the divide between tributaries of the Vermilion and streams that flow westward to the Illinois. From this divide eastward to the Vermilion River the surface shows very little undu- lation. There is, however, a marked descent, the altitude of the divide being 700 to 750 feet, while the immediate borders of the Vermilion north from Pontiac stand but 620 to 640 feet above tide. The descent from this divide westward to the Illinois is very slight; indeed, in places east-west lines are nearly level from this divide to the border of the river valley. There is a small tract south of Ottawa, occupying the interval between the inner ridge of the Bloomington system (Farm Ridg-e) and the Mar- seilles moraine, which has a nearly plane surface. It is crossed in an east- west direction by a sand ridge, discussed below. Another sand ridge follows the south bluff of the Illinois part way across this plain. Both 282 THE ILLINOIS GLACIAL LOBE. ridges appear to mark the shores of a lake-like expansion of the Illinois River, and represents two stages differing about 30 feet in level. In northern McLean County a tract embraced between the inner border of the main ridges of the Bloomington system and the Mackinaw River Valley is gentlv undulating and is also dotted by occasional well-defined knolls 20 or 30 feet in heig'lit. It has a marked northward descent, the elevation along the Mackinaw River being 50 to 100 feet below the inner border of the moraine. North from the Mackinaw River, as alreadv noted, there is a well-defined ridge (Cropsey Ridge) crossing the country in a WNW.-ESE. direction. From this ridge there is a gradual northeastward descent toward the Vermilion River. The greater part of the surface is plane or but gently undulating. There are, however, in southern Living- ston County a few knolls and ridges of sand 10 or 20 feet in height. These knolls and ridges are probably the result of wind action rather than glacial features. East from the reentrant angle of the Bloomington morainic system in Ford and southeastern Li^■ingston counties there is a plain which covers the greater part of Iroquois County and extends slightly into bordering- counties. The plain is bordered at the north by the ^Marseilles morainic svstem and at the east by the Iroquois moraine, a moraine of late ^Visconsin age. It extends into the State of Indiana only a few miles, in northwestern Benton County. This plain descends toward the north, its altitude at the inner border of the Bloomington morainic system being about 700 feet and in northern Iroquois County only about 625 to 650 feet. It is crossed nearly centrally from east to west by a gently undulatory belt, discussed above as a possible continuation of the inner member of the Bloomington system. Aside from this belt the drift surface is nearly plane. There ai'e, however, a few low sandy ridges in the western part of Iroquois County and numer- ous dunes in the eastern part. Some of these ridges appear to be beaches of a temporary lake, as indicated below. The dunes ai-e, in all probability, a result of wind action upon the sand deposits of the lake bottom. THICKNESS OF DRIFT. There are present beneath these intermorainic tracts a sheet of fresh drift of Wisconsin age and older deposits of lowan and Illinoiau age. The thickness of the Wisconsin ilrift may be ascertained at manv places by the THE BLOOMINGTON MOEAINIC SYSTEM. 283 well records, which show a change from soft till to hard at the base of this deposit. It is much less than on the morainic ridges of the Bloomington system, and probably does not average more than 50 feet. In southern Kane County and thence southwest along the border of Fox River it appears to be but 20 to 40 feet, but at the inner border of the main moraine in Dekalb, Lasalle, and Bureau counties it is in places 100 feet or more. In the counties bordering the Illinois River it is 50 to 100 feet or more, but in the Vermilion Basin it scarcely reaches 50 feet. In Iroquois County it is 50 to 100 feet. The older drift deposits are thin in the vicinity of Fox River and Vermilion River and the west-flowing portion of the Illinois River, but elsewhere within the tracts under discussion they are generall)^ present in large amount, and there is probably an average thickness as great as that of the Wisconsin drift sheet. In portions of the Iroquois River basin 200 feet or more of the older drift is present, but in the remainder of the tract a thickness exceeding 100 feet is i-are. By reference to the detailed dis- cussion of the wells in the several counties embraced within these inter- morainic tracts the variations in thickness may be seen. STRtlCTtIRE OF THE DRIFT. Throughout the greater part of the area embraced in these inter- morainic tracts the Wisconsin di'ift consists mainly of a moderately stony, soft, blue till, very similar to that found in the moraines. This till is replaced by sand or gravel deposits along the line of the eskers which occur in Kane and Dekalb counties, and also along many of the tributaries of Fox River. There is also considerable sand associated with the till in a belt several miles in width along the west side of Fox River in Kane, Ken- dall, Dekalb, and Lasalle counties. On the borders of the Vermilion River in Livingston County and southern Lasalle County sand and gravel deposits predominate over the till. With these exceptions the till greatly predomi- nates over the sand and gravel. In many localities it forms so solid a sheet that strong wells are not obtained in it, whereas in the districts in which sand and gravel predominate over the till abundance of water is obtained at moderate depths. The drift of these intermorainic tracts is capped only by thin deposits of silt, seldom exceeding 3 feet in depth, and in places too thin to conceal the surface bowlders. 284 THE ILLINOIS GLACIAL LOBE. The older deposits of di-ift appear to be more variable tlian the Wis- consin sheet within the area under discussion. The till differs from that of the Wisconsin sheet in being' much harder to penetrate and in being of a gray or brown color rather than blue. It appears to contain numerous pockets or intercalated beds of gravel or sand, for strong wells may usually be obtained in it in localities where the Wisconsin drift does not supply a sufficient amount of water. The outcrops of these older deposits along the ravines or A-alleys tributary to the Illinois often expose a cemented gravel, in beds a few feet in thickness and a few rods in extent. These beds appear to lead through the till in horizontal bands of limited width ; pos- sibly they are buried stream beds or valley gravels formed between the reti-eats and advances of an oscillating ice margin. The exposures are insuflicieut to aff'ord a clear idea of their extent and connection. It seems not improbable that these beds which are cemented at outcrops along- the valleys become open textured and water bearing- where unexposed. There are places along the Illinois Valley and its tributaries where the older drift appears to be composed very largely of sand and gravel, but as a rule the till predominates. The structm-e of the drift in each of the counties com- prised in this intermorainic area is shown in some detail in the discussion of wells which accompanies this report. KANEVILLE ESKER AND DELTA. One of the most interesting eskers noted in Illinois is found in the southern part of Kane County. Its eastern terminus is about 3 miles west of the city of Aurora, and its western terminus is near the \'illage of Kane- viUe, from which the esker has received its name. The esker occupies a trough-like valley cut in glacial deposits. It is probable that the valley was formed by the same stream which deposited the esker, since they coin- cide so nearly in trend and position. At the western end of this valley there is an extensive delta, apparently built up by the same stream. The troi;gh- like valley is now travei'sed by Blackberry Creek in the reverse direction from the supposed flow of the glacial stream which produced the excava- tion and formed the esker and delta. The valley occupied by the esker is much larger than that of the lower course of Blackberry Ci'eek, its dimen- sions being about 1 mile in width and 30 feet in depth, while the valley of the creek below the point where it leaves this trough is scarcely 20 I'ods in U.S.GEOLOGIGAL SURVEY. MONOGRAPH XXXVIII PL. XIV. R 6 E R 7 E R 8 E R.6 E. R.7 E. R.8 E. JULIUS aiEN a CO. ".f ■i iiii ill ■ [^ ^ Morainic Undulating til! Till plain Sandand gravel Bowlderhelts Kiollsina Ixanevilleesker Slxice plainsaiidterraces S'ravelplain GLACIAL MAP OF PARTS OF I\ANE AND liENDALL COUNTIES BY FRANKLEVERETT Scale 1898. THE BLOOMINGTOK MOEAINIG SYSTEM. 285 average width and but 16 or 20. feet in depth. The trough-like valley is therefore about 30 times as large as the portion of Blackberry Creek Val- ley below its eastern end. This broad valley was apparently cut to such depth before the creek entered it that the latter has tended to fill it by over- flows in time of freshet, and has deepened it only in the immediate bed of the stream. The eastern end of the esker is found in sec. 18, Aurora Township, on a till plain which borders Fox River. There is here a ridge of gravel some 60 rods in length and 10 or 20 rods in width, which rises but 12 to 15 feet above the bordering plain. For a mile or more west from this ridge there ai'e only occasional small gravel deposits in the form of knolls and short ridges, but as soon as the trough-like valley is fairly entered the gravel becomes more abundant. (See PI. XIV.) It forms a winding- ridge 20 to 60 feet in height, and inteiTupted only by occasional narrow gaps. Its slopes are very abnipt, rising frequently with an angle of 30°. In the northwest part of sec. 31, Blackben-y Township, about 7 miles from the eastern end, the esker rises from the deeper portion of the valley and lies along its south slope. Here also it changes from a single sharp ridge to a tumultuous series of knolls and winding ridges, inclosing basins 30 to 40 feet or more in depth and having a diameter of but 10 or 20 rods. This belt has a width of about ^one-third of a mile, and extends westward nearly a mile. Just north of this main belt there are, in the deeper part of the valley, occasional gravel knolls and low winding- ridges. These low ridges rise from the trough at its western end, and together with the main belt lose themselves in the gravel delta near Kane-\dlle, the delta being built up nearly as high as the crests of the ridges. The delta occupies an area of about 8 square miles. It stands a few feet higher than the till plain which borders it on the north, west, and south. The gravel apparently extends in places below the level of this till plain, for in two cases wells have penetrated to a depth of 60 feet without reaching its bottom. In the village of Kaneville, which is situated in the midst of the delta, the wells are usually in gravel to a depth of 30 or 40 feet. In a few instances, however, clay beds were passed through in the lower portion of the wells. There are numerous small excavations in the esker which show it to be formed of sand and gravel in neai'l}- horizontal beds. In places the beds 286 THE ILLINOIS GLACIAL LOBE. have a sharp dip toward the sides of the esker, but this does not appear to be a general attitude. The upper part and frequently the slopes consist of coarser gravel and contain less fine material than the deeper portions. The absence of fine pai'ticles is perhaps attiibutable in part to the action of per- colating waters, which probably have sufficient force to carry down the finer particles a few feet from the surface, but it is probable that the sm-face portion was originally coarser than the deeper beds. The pebbles are mainly limestone and are appai-ently, in large part, from the Lockport (Niagara) limestone, which outcrops in the neighboiiug district on the east. The sand is calcareous, but not to such a degree as in many hillocks containing sand and gTavel which occur in the neighboring moraines. It seems probable that the material of which the esker is composed is a residue left upon the exca- vation of the till which was removed along the course of the valley or of material embedded in the basal portion of the ice sheet. Examinations of a sample of the till from a neighboring till plain showed that 93 per cent of the pebbles are limestone, which is about the percentage of limestone in the esker. Bowlders were observed on the esker in but one place, and this was at a slight depression on its crest. There were about 30 of them, and all were of Archean rocks. The greater percentage of Ai-chean rocks on the sui-face than in the deeper portions, both of eskers and till sheets, appai-ently indi- cates a different source for the bowlders than that of the main body of the drift. Presumably they were carried at a higher elevation in the ice. • LITTLE ROCK ESKER OR "DEVIL'S BACKBONE." In the northwest part of Squaw Grrove Township (T. 38, R 5 E.), Dekalb County, there is an esker about 1 ^ miles in length, known by the residents as the " Devil's Backbone." It is situated a short distance south of Little Rock Creek in sees. 5 and 6, and trends ESE.-WNW. At the eastern end its height is but 4 to 6 feet, but in sec. 6 it is 10 or 15 feet in height. It is onl)^ 8 or 10 rods in width, including slopes, and consequently presents very abrupt slopes. It winds considerably, but has a somewhat even crest line. At the western end there is a sandy tract covering about 80 acres, which is thought to be a delta formed in connection with the esker. There is no valley or trougli excavated in the di'ift, as in the case of the Kane- ville esker, for tlie esker stands at aljout tlie level of the bordering till plain. THE BLOOMINGTOK MORAINIO SYSTEM. 287 Wells in the delta penetrate 10 to 15 feet of sand before entering till. The esker is opened at numerous points, and there is usually 3 or four feet of coarse gravel at the surface, beneath which is a finer gravel. In jjlaces the bedding is found to have a dip toward the northwest, nearly in line with the general trend of the ridge. The coarse gravel curves over the ridge, covering slopes as well as crest. The pebbles are principally limestone and are usually well rounded. There are a few short gravel ridges and knolls east from the end of this esker in sees. 4, 11, and 12, but they do not seem to be definitely connected with one another or with the esker. Their trend, like that of the esker, is ESE.-WNW. The same system of glacial drainage which formed the esker may have been influential in forming these knolls and ridges. Mention should also be made of a chain of gravelly knolls which follows a tributary of Somonauk Creek in southeastern Clinton Township (T. 38, R. 4 E.), Dekalb County. Though following the creek border closely, they are evidently not the result of erosion by the creek, for they stand above the general level of the bordering plain. They range in height from 10 to 25 feet. Their width is iisually 15 to 30 rods and the length varies from one-fourth mile or less to fully one-half mile. They are chiefly on the south border of the stream, but two were obsei-ved on its north border. They are not strictly in line with each other, though a belt a half mile wide would include the entire system. The length of the system is about 4 miles, the western end being 2^ miles south of Waterman and the eastern end at Somonauk Creek Valley in the southwest part of Squaw Grrove Township. One of these knolls has an extensive gravel pit in which the following beds are exposed: Section in gravel pit on hnoll in Clinton Toivnship, Dekalb County, Illinois, Feet Brown clay -with a few clierty pebbles 4 Coarse gravel, maiuly limestone pebbles 6 Fine gravel and sand in alternate layers, each 6 inches or more in thickness 4 Several other small excavations have been made in these gravel knolls which show a section similar to the above. The stratification in every case is nearly horizontal. There are also knolls of a different tyjoe found on this plain which include much till as well as assorted material. One of these knolls, situated about 2 miles northwest of Leland, contains an extensive gravel pit which 288 THE ILLINOIS GLACIAL LOBE. displays its stracture from top to bottom. The knoll is capped by a browu clay, containing few pebbles. Beneath this there is at the east side of the knoll considei'able sand, but toward the center there is a series of till or clay beds 12 to 20 inches iu thickness, interstratified with gravel and sand beds each 2 or 3 feet in thickness. All the beds dip toward the center of the hill at an angle of 15 degrees or more. The till is very hard and pebbly. The gravel contains a much larger percentage of crystalline rocks of Canadian derivation than is common in knolls and eskers made up eutu'ely of assorted material, though there are many limestone pebbles such as may have been derived from ledges in the neighboring districts on the east. This knoll stands 15 to 20 feet above the bordering plain and about 30 feet above the flood plain of Little Indian Creek, which touches it on the east. COVEL RIDGE. In the plain di-aiued by Covel Creek, a southern tributary of the Illinois, entering just below Ottawa, there is a low ridge about 7 miles in length extending in a nearly due east-west direction from near the outer border of the Marseilles moraine in sec. 4, Grand Rapids Township (T. 32, R. 4 E.), to the inner slope of Farm Ridge the inner ridge of the Bloomington system in sec. 5, Farmridge Township (T. 32, R. 3 E.). It has a height of 15 or 20 feet and a width of 40 to 60 rods, and is interrupted by no gaps of consequence except the one through which Covel Creek passes in sec. 6, Grand Rapids Township, and this gap is only 30 or 40 rods in width. The altitude of the crest of this ridge, as shown by the Ottawa topographic sheet, a portion of which is reproduced in PI. XIX, is mainly between 640 and 650 feet above tide. The portion east of Covel Creek is represented to be slightly lower than 640 feet. The ridge is capped b}" a brown silt several feet in thickness which is readily peiwious to water. This is underlain by sand which extends to a depth of 15 or 20 feet or more. The few wells which have been made on the ridge are sunk no deeper than 20 feet. The sand also extends oiit beneath the bordering plain a short distance both north and south of the ridge and affords water for wells at slight depth. The extension beneath tlie plain, however, seldom exceeds a mile in width or half a mile from the crest of the ridge. Border districts are underlain at slight depth by till. The internal structure, the form, and the uniform elevation of tlie ridge THE BLOOMIjSTGTON MORAINIC SYSTEM. 289 suo-o-est the interpretation that it is a beach Hne. However, this interpreta- tion scarcelv affords a satisfactory explanation of the mode of deposition of the silty mantle; hence the question of its mode of formation is left open. There is a lower ridge following- the brow of the Illinois bluff, which is well displaj^ed in South Ottawa, and eastward from there to the border of the Marseilles moraine. Its altitude, as shown by the Ottawa topo- graphic sheet, is very nearly 610 feet above tide. Along- the north bluff of the Illinois, about midway between Ottawa and Marseilles, there is another beach-like ridge leading from the outer border of the Marseilles moraine westward to the border of Fox River Valley, which is represented to stand a few feet lower than the ridge just noted, its altitude being 600 feet or less. ONARGA RIDGE. In the Iroquois Basin there are several small ridges of sand presenting the appearance of beach lines, some being found in the northwest part of Iroquois County, a short distance south of the Marseilles moraine, and others on portions of the plain farther south. The best-defined and most elevated ridge noted is one leading from Onarga westward through Ridge- ville to one of the headwater forks of Vermilion River, the west end being near the line of Iroquois and Ford counties, about 4 miles southeast of Piper. Throughout this distance of about 8 miles it has a width of only 40 to 80 rods and a height of 15 or 20 feet or less. As far as could be ascertained from the slight exposures and records of occasional wells it is composed entirely of sand. It is underlain at the level of its base by a bluish-yellow, silty, pebbly clay, which grades below into bliie till. In some places the sand is immediately underlain by blue till. As a rule the ridge has a smooth surface and gentle slopes, but in places the sand is drifted into low dunes 6 or 10 feet in height. The sand is of a brown color and so far as tested shows no effervescence with acid. A short distance east from the eastern edge of this ridge a belt of low sand dunes sets in, which has a width of 1 to 2 miles. This belt leads eastwai'd to the vicinity of Watseka, and thence northward and eastward to the Kankakee Basin, occupying much of northeastern Iroquois County. The elevation of the Onarga Ridge is about 675 feet above tide, but the duues to the east seldom reach this elevation, the district covered by them HON xxxvm 19 290 THE ILLINOIS GLACIAL LOBE. having- generally an elevation of 640 to 650 feet. Possibly a shore line may be found south and east of the dunes at an elevation corresponding to that of the Onarga Ridge, but as yet it has not been discovered. It seems probable that this ridge marks the south shore of a temporary lake which discharged westward through the east fork of Vermilion River. If there were no obstructions at the north, a northward discharge from the Iroquois Basin would seem to be more natural, for the country descends in that direc- tion. The only known former obstruction is that caused by the presence of the ice sheet, in which case this beach may be interpreted as the shore of a glacial lake. The writer's studies have not been sufficiently detailed to justify a full interpretation of the phenomena. Other features of similar character are discussed below (pp. 336-338). SECTION IV. THE COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. Numerous references have been made in previous pages to a composite belt of moraines with which the Bloomington system connects in northern Kane County, and which marks the continuation of the Bloomington system, together with that of later morainic systems which are there intimately associated with it. This composite belt admits of but little separation into distinct moraines. It seems advisable, therefore, to give it treatment inde- pendent of each of the morainic systems which lead away from it, leaving open to a large degree the question of precise correlation. This belt is made to include a somewhat distinct moraine, called the Marengo Ridge, which lies along its western border. The discussion of this ridge is first taken up ; the remaining portion of the composite belt west of Fox River is next considered, and this is followed by a discussion of the portion east of Fox River. MARENGO RIDGE. DISTRIBUTION. North from the village of Hampshire in Kane County, as far at least as the State line, the Marengo Ridge constitutes the outer moraine of the Wisconsin series, and it probably continues to be the outer moraine to its junction with the Kettle moraine of the Green Bay lobe in western Wal- worth County, Wisconsin.' Tlie ridge receives its name from the village of 'SeeT. C. Chamborliu; Third Ann. Rept. U. S. Geol. Survey, p. 322; also PI. XXXI. COMPOSITE MOEAINIC BELT OF NORTHBRX ILLINTOIS. 291 Marengo, which is situated in the line of the ridge, but wliich stands in the North Kishwaukee Valle j. It is the only town in Illinois in the direct line of the ridge, though Harvard in McHenr)?- County and Hampshire in Kane County are situated near the foot of the outer slope. From the State line the course of the ridge is nearly due south to Marengo, from which point it bears southeast to the south line of McHenry County. It then resumes a southward course and continues for about 18 miles to the vicinity of Elburn, in Kane County, where it becomes united with the portion of the composite belt to the east. It will be observed that it passes by the eastern end of the outer Bloomington ridge near Hamp- shu-e. The ridge thi'oughout the greater part of its course has a width, including slopes, of 3 or 4 miles. BELIEF. The relief of the outer border is seldom less than 100 feet, and in places it reaches 150 feet or more. The inner border has a relief of 75 to 120 feet, but the relief appears less bold than on the outer border, because the ascent to the crest is more gradual. This ridge is closely associated with the remainder of the belt for a few miles south from the State line, and differs but little in altitude from the district on the east. Similarly at the south, where it connects with the remainder of the belt, it has about as great an altitude. SURFACE CONTOUES. From the State line southward to Hampshii-e this ridge presents a char- acteristic knob-and-basin topography, so well develojied in the Wisconsin Kettle moraine and described by Chamberlin as being "of an exceedingly irregular, intricate character, formed by knobs, peaks, short irregular hills and spurs associated in complex order, interspersed with hollows and depressions of like irregular character, often without outlet."^ The larger knobs rise scarcely 50 feet above the neighboring basins, and the average height of the knobs is probably not more than 25 feet. They are found both on the crest of the ridge and on the slopes. Aside from the well-defined basins, there are shallow, saucer-like depressions found frequently on the top of the knolls and the slopes of knolls and ridges, as well as in the sags between them. There is a marked distinction between the contours of the prame ' Third Ann. Kept. U. S. Geol. Survey, 1883, p. 307. 292 THE ILLmOIS GLACIAL LOBE. aud of the wooded portion of the ridg-e, the contours being niucli sharper in the forest than on the prairie. The ridge is mainly forest-clad from the State line sonth to the vicinity of Hampshire and mainly praii-ie from Hampshire to Elburn. This difference in the sharpness of contour may be due in part to the effect of the agencies of degradation, the wooded portion of the ridge being better protected from these agencies. It is probable, however, that the prairie portion was originally possessed of smoother con- tour. It presents a series of billows, often 40. or 50 feet high and 60 to 80 rods or more in diameter, whose slopes are usually smooth and regular. As indicated below, the relation of the southern portion of the ridge to the ice margin may be somewhat different from that north of Hampshire. There are three gaps in this ridge worthy of mention. The largest is that at Marengo, through which the North Kishwaukee passes. It is fully 150 feet in depth and about 2 miles in width. The second gap occurs about 5 miles southeast of Marengo. This is nearly a mile in width, but only about 76 feet lower than the neighboring portions of the ridge. It has a nearly plane surface, and has apparently been utilized as a line of discharge for a body of water formerly held between this ridge and the one on the east. A third gap occm-s in the north part of T. 40, R 7 E. It is 60 or 70 feet in depth and about one-half mile in width. It has a nearly plane surface and was probabl}?" at one time a line of discharge for water held between this ridge and a moraine on the east. It is now utilized by a trib- utary of the South Kishwaukee River. THICKNESS OF DRIFT. The thickness of drift has been ascertained at only three points, but records of several deep wells were obtained which show that there is a heavy accumulation along the entire length of the ridge. Of the three borings reaching rock, one is in the village of Harvard and the other two are in the southern part of the ridge. At Harvard the thickness is 102 feet. In the other weJls the rock was struck in one instance at 230 feet and in the other at about 250 feet. It is probable that the general thickness of the drift along the crest of the ridge south from Hampshire is not far trom 250 feet, for wells on the plain west of the ridge, at an altitude 100 to 125 feet below the level of its crest, have in several instances struck rock at about 150 feet. One well on the ridge, near Lily Lake reached a depth of 336 feot without COMPOSITE MOEAraiO BELT OF NORTHERN ILLINOIS. 293 entering rock. In the portion north from Hampshire the thickness is prob- ably not much greater than the rehef of the ridge, for rock is enconntered at a depth of 50 feet or less in much of the border district on the west. The drift referable to the invasion which formed this ridge has probably a thick- ness about equal to the relief of the ridge, which, as stated above, is usually 100 to 150 feet or more. STRUCTURE OF THE DRIFT. The ridge is composed mainly of blue till. Sand and gravel beds are not sufficiently extensive to afford a general water supply. Even weak wells are difficult to obtain in some parts of the ridge. Many wells must be sunk 100, 125, or even 150 feet to obtain an adequate water supply. In not a few instances the water supply appears to be obtained at about the level of the base of the ridge and the junction between the Wisconsin and older drift sheets. A few gravelly knolls were noted along- the outer border of the ridge west of Marengo, and at occasional points between there and Hampshire. None of these rise more than 10 feet above the general level. A few gravel knolls were noted near East Bin-lington, in sees. 23, 24, 25, and 26, T. 41, R. 6 E., and low gravel ridges occur along the ti'ibutaries of the South Kishwaukee in Ts. 40 and 41, R. 6 E. Excavations in these knolls usually show a preponderance of sand and gravel over till, though the latter is often present in considerable amount. The beds have no apparent uniformity in direction or degree of dip. They are often curved and disturbed as if affected by movements of the ice sheet over them. The presence of a buried soil was noted in several well borings of which records were obtained. In the city of Marengo, on the borders of Kishwaukee Valley, it is found at a depth of 30 to: 60 feet, the variation in distance being due to difference in elevation of the wells. In sec. 11, T. 43, R. 5 E., a well on the outer slope of the moraine struck a buried soil at 70 feet. The soil was underlain by a soft whitish clay of slight depth, beneath which gravel, 5^ielding water, was found. In the cases just noted the soil seems referable to the Peorian interglacial stage. A buried soil was noted in one of the deep borings in T. 40, R. 7 E., which reached the bottom of the drift. This soil, as noted on a preceding page, seems to be at a level low enough to be referred to the Sangamon. The boring is on 294 THE ILLINOIS GLACIAL LOBE. the farm of James Powell, in sec. 7, near the crest of the ridge, and the section is- as follows: Section of James PoicelVs boring near Lily Lake, Illinois. Feet. Pebbly soil 1 Brownish-yellow pebbly clay 15 Graj'ish-blue pebbly day 180 Black mucky soil 2 Greenisli clay 3 Hard pebbly clay of brownish-blue color 40 Santl 2 Hard clay 8 Limestone 200 Total depth 450 The thickness of the yellow till in the above well section is greater than the average, though instances were found in which the till presented a yel- lowish color to a depth of 35 feet from the surface. The average depth of the yellow till is about 10 feet. Several sections of wells along this ridge are presented below in the discussion of the wells of Illinois. The till is thought by some well di-illers to be slightly more stony in the ridges than on plane tracts in McHenry and Kane counties, but the difference is not very marked. Surface bowlders are common over the entire length of the ridge, and in a few places are very numerous. They are especially abun- dant in the vicinity of the McHenry-Kane county line and also near East Burlington. Bowlders are composed mainlj' of granitic and other rocks of Canadian derivation, limestones and local rocks being rarely found at the surface. In the till, however, limestone rocks are a conspicuous ingredient, and also in the kames or gravelly knolls. CHARACTER OF OUTWASH. Along the outer or western border of this ridge from the State line southward to Hampshire there is a nearly continuous gravel plain formed apparently as an outwash from the ice sheet. It extends out usually a mile or more from the foot of the moraine, and leads westward down the Kish- waukee Valley to Rock River. From Hampshire southward the plain out- side ^Marengo Ridge is nearly free from coarse outwash and carries only slight deposits of silt and sand. Tlie gravel plains usually have a capping of loamy clay 2 to 6 feet or more in depth, which gives them great fertility. Beneath this clay ^re beds of sand and gravel which show considcrahlc variety in coarseness in vertical ti' COMPOSITE MOEAINIC BELT OF NORTHERN ILLINOIS. 295 section. They vary also iu coarseness from place to place at the same hori- zon. On the border of the gravel plains the assorted material rests upon beds of till belonging- to the older drift, and the depth is often insufficient to afford water for wells. In the middle portions of the gravel plains the wells do not reach the bottom of the sand and gravel. Along the Kish- waiikee near Marengo, Capt. Fred Smith, a well driller, has in some cases Slink wells to a depth of 100 feet mainly through gravel, but it is not cer- tain that this deposit should be entirely referred to the outwash from the ice at the time the Marengo Ridge was forming. INNEK-BOEDER PHENOMENA. On the inner border of the Marengo Ridge there is, in Kane County, a narrow plain 1 to 2 miles in width, separating it from the remainder of the composite belt. This plain is generally very level and in places is poorly drained. It is underlain in part by sand and in part by till. The greater part is now tributary to Fox River, but the southern portion finds a discharge westward into the Kishwaukee through a gap in the Marengo Ridge, as noted above. In McHenry County the inner border of the Marengo Ridge is largely occu^jied by gravel plains which are connected with the portion of the composite belt on the east. Along the borders of these gravel plains there are nearly level tracts underlain at slight depth by till. At present the gravel plains on both the inner and the outer border of the Marengo Ridge are occupied b}^ insignificant streams which seldom fill the small ditches leading through the broad plains. They are certainly inadequate to have deposited tlie vast amount of assorted material here present, and the fact that these gravel deposits set in at the base of the moraines in just such positions as streams of water escaping from the border of the ice sheet would occupy, apparently leaves no room to question the interpretation that the gravel is an outwash from the ice margin. These gravel deposits, it is thought, testify as clearly, though perhaps in a less impressive manner, to the influence of the ice sheet as does the great ridge of commingled drift formed at the ice border. CORRELATIONS. The correlations of this ridge with moraines farther south can scarcely be said to be settled. Several interpretations are suggested by the 296 THE ILLINOIS GLACIAL LOBE. phenomena. By one interpretation tlie portion of tlie ridge from Hampshire northwai-d is considered a continuation of the Bloomiugton system, while the portion south from Hampshire is merely a spur projecting back from the reentrant angle formed near that A'illage. The difference in the contours of these two portions of the ridge may in this case be due to a different position in reference to the ice margin, the portion north from Haiupshire being formed at the extreme margin of the ice sheet and the portion south fr(im. Hampshire at some distance back from the margin; The submarginal position would seem to be a sufficient cause for the smootlmess of contour. By a second interpretation the Marengo Ridge is made later than the outer ridge of the Bloomington system, and its entire length considered a marg'inal accumulation. Its great relief above the outer ridge of the Bloomington systejn at Hampshire, where it crosses that ridge, so strongly favors this interpretation that for some years it was given more weight by the writer than other interpretations, though the absence of a gravel out- wash on the west border of the portion south from Hampshire left room for doubt. A third interpretation suggested itself when revisiting the region with a view to reaching a more satisfactory conclusion concerning correlations. By this interpretation the outer ridge of the Bloomington system is con- sidered to pass eastward across the Marengo Ridge and to join the composite belt lying east of that ridge. The portion of the Marengo Ridge north of Hampshire would, in this case, have stood outside the ice sheet, while the portion south of Hampshire would have been overridden by it. If ihe weakness of the outer ridge of the Bloomington system at the point where it connects with the Marengo Ridge is continued eastward some difficulty would Ije experienced in tracing it over the more bulky and more sharply morainic Marengo Ridge. The abrupt change in the contour of the Marengo Ridge at the point where the outer ridge of the Bloomington system con- nects with it seems to give supjDort to this interpretation, as well as to the first interpretation. Until further liglit is thrown upon the subject, the value of each of these interpretations nuist remain an open question. At present the writer is unable to exclude any of them, nor does any one of them seem decidedly better sustained b)- the phenomena than the others. to COMPOSITE MORAINIG BELT OF NOETHERN^ ILLIl^fOIS. 297 PORTION OF COMPOSITE BELT W^EST OF FOX RIVER. GENERAL FEATURES. Aside from the Marengo Ridge just described, there is a belt from 8 to 15 miles in width, on the west side of Fox River, in McHeniy and Kane counties, which is strongly morainic, there being only a few small areas, of 1 to 3 square miles each (aside from marshes and swamps included among the morainic knolls), in which the surface is level. The belt is more elevated on the west border than in the A-icinity of Fox River. Its general elevation there is not markedly different from that of the crest of the Marengo Ridge. At the State line it rises above the 1,000-foot contour, one point being 1,040 feet above tide (Rolfe). A point a mile south of Alden rises above 1,000 feet. Along much of the divide between the Kishwaukee and Fox rivers, from the State line southward to Crystal Lake, the altitude is above 950 feet. In southern McHenr}^ County and in Kane County few points reach 950 feet, but much of the divide rises above 900 feet. Fox River enters the State at an elevation of 766 feet (Rolfe) and falls about 25 feet in crossing McHenry County, a distance by course of stream of over 30 miles. In Kane County its descent is more rapid, there being a fall of 125 feet in a distance no greater than that traversed by the stream in McHeni-y County. The stream is in the midst of morainic knolls and ridges as far south as Geneva, beyond which it has a plain on its west border. These ridges often rise abruptly 80 or 100 feet above the level of the stream. From the valley of Fox River, in McHenry and Lake counties, marshy valley-like tracts extend back several miles to the west and 2 to 3 miles to the east. These are traversed by sluggish streams similar to the upper com-se of the river. Although the western border of this composite belt is, on the whole, more elevated than the district immediately bordei'ing Fox River, it does not present so rough a surface, except perhaps in central Kane County, where a few square miles present a very sharp knob-and-basin topography. If a strip 3 or 4 miles wide along the west side of Fox River be excepted, the moraine in McHenry County presents few knolls that exceed 40 feet in height. The great majority are 25 feet or less. On the borders of Fox 298 THE ILLINOIS GLACIAL LOBE. River, as already noted, ridges and kuolls in some cases reach a lieig'ht of 80 or 100 feet. Numerous saucer-like depressions and occasional well- defined basins appear in all parts of this belt. In northeastern McHeniy County there is a small gi-avel plain known as "English Prairie," which stands about 100 feet above Fox River and occupies perhaps 3 square miles. It is about as elevated as neighboring portions of the moraine and is bordered by morainic knolls and ridges on every side. In the vicinity of Crystal Lake and Cary, in southeastern McHenry County, there is an elevated gravelly tract covering several square miles in which the surface is gently undulating and more subdued in expression than neighboring tracts composed more largely of till. The surface is not so level as in English Prairie. Immediately noiih of this gravelly tract, in the vicinity of Terra Cotta, there are broad swampy ti'acts ■ nearly as low as Fox River which separate prominent ridges trending NNE.— SSW. These ridges continue prominent throughout the greater part of Ts. 44 and 45, R. 8 E. In northern Kane County there are small plane tracts standing nearly 200 feet above Fox River which have been di'ained by an extensive system of ditches. These are almost completely suiTOimded by morainic knolls which rise 20 to 40 feet above their surface. Some of these knolls near Gilbert are very sharp. In the vicinity of the line of McHenry and Kane counties Fox River is bordered on each side by morainic tracts nsing 150 feet or more above the level of the stream, and there is scarcely any marshy land on its borders southward from this line. From the vicinity of Elgin southwestward to Lafox there is a belt 3 or 4 miles in width on the west side of Fox River in which sharp gravelly knolls and ridges abound. These ridges and knolls show a tendency to arrangement in chains trending nearly east-west, or about at right angles with the trend of tlie morainic belt. There are, however, not a few excep- tions to this trend, some ridges being nearly in line with the morainic belt. These gravel ridges constitute the most ])rominent features in this portion of the moraine, many of them being 30 to 40 feet and a few 00 to 75 feet in height. The}' often rise very abruptly, so that their slopes are cultivated with difficulty. In the majority of cases these chains of laiolls and ridges folloM' depressed areas standing 50 feet or more below the general level, and the present di-ainage lines in traversing these low belts wind about COMPOSITE MORAIlsIC BELT OF NORTHERN ILLINOIS. 299 among- the g-ravellj ridges. In a few cases the knolls and ridges appear on elevated parts of the district. In Campton Township (T. 40, R. 7 E.) the moraine is very elevated, some points reaching nearly 1,000 feet above tide, and presents a very sharp knob-and-basin topography. It has probably the sharpest knobs and the deepest basins found in the State of Illinois. The highest points rise about 150 feet above the border districts on the south and west and more than 200 feet above Fox River. Oscillations in level of 75 feet in a distance of 30 to 40 rods are not uncommon, and several beautiful lakelets of an acre or more each are sunk deeply in the midst of morainic knolls which surround them. This very strongly morainic topography appears at the point where the inner belt of the Bloomington morainic system connects with the com- posite belt under discussion. It also terminates the prominent portion of the composite belt so far as developed west of Fox River. Upon passing southward from Campton Township a miicli lower country is entered than that to the north, the descent being similar to that found in passing southward from the inner border of the Bloomington morainic system in western Kane, Dekalb, and Lasalle counties. But instead of passing into a plane-surfaced tract, siich as occurs on the inner border of the Blooiuington S5^stem, an undulating tract is entered, which extends south to the border of Kendall County in a belt several miles wide. This tract contains a few very prominent knolls. One, known as Johnsons Mound, situated near the east fork of Blackberry Creek in sec. 15, T. 39, R. 7 E., rises about 150 feet above the level of the creek and covers fully 50 acres. A second prominent knoll, known as Bald Mound, because desti- tute of trees, is situated in sec. 23 of the same township. It rises about 80 feet above the border districts and covers perhaps 100 acres. It is elongated in a north-south direction, its length being about three times its width. Its southern end rises abruptly, but at the north it descends gradually to the gently undulating tract which borders it. A third knoll, known as Wash- burn's Mound, is situated between the other two in sec. 14, and stands about 50 feet above the bordering country. This mound is also elongated north to south, and has a length of one-half mile and a width of 40 to 60 rods. This mound has a more regular border than the other two, for they present spur-like projections which extend out 20 to 40 rods beyond a regular border. Aside from the three prominent mounds just mentioned the knolls 300 THE ILLINOIS GLACIAL LOBE. seldom reach a height of 25 feet, and many of them are 10 feet or less. The Kane%'ille esker described above has its trough mainly within this nndulatory belt, but the delta lies entirely west of it in a very level countr}-. There are occasional narrow sloughs or depressed areas 10 or 15 feet below the general level, which in most cases have connection Avith the present drainage lines. The upper course of Blackben-y Creek is through a series of slightly depressed marshy tracts which occur among the low knolls of ' this xindulatorr belt. The undulations are maintained as far south as the line of Kane and Kendall counties, the southern terminus being at a gravel plane leading down Fox River. There is a narrow till plain between this nndulatory belt and Fox River from Geneva southward similar to the plain which borders it on the west. STRUCTURE OF THE DRIFT. The drift of this portion of the composite belt is much more variable in structure than the Marengo Ridge. On nearly ever}- section except in the gravelly belts above noted wells have shown that both till and assorted material are present. The till apparently preponderates over the assorted material, for the latter usually occm-s in thin beds. In the gi-avel plain known as English Prairie and in the gravelly belt between Crystal Lake and Fox River there appears to be httle or no till within 100 feet of the surface. The di-ift is mainly gravel and cobble, there being but little sand. In places fine laminated clays appear at some depth beneath till and grav- elly deposits. The Illinois Central Railway exposes such beds in the deep cuts east of Plato Center. The till appears to be oxidized at surface to greater depth on this portion of the composite belt than on the Marengo Ridge, a feature which is probably attributable to the greater coarseness or porosity of the till, for it can not be older than the Marengo Ridge. In some cases the oxidation extends to a depth of 50 feet or more. However, the till is not everywhere coarse textured, for on some of the level tracts among the raorainic knolls it is very compact. On low tracts near Terra Cotta, in eastern McHenry Count}-, there is a compact silt used extensively for tile and also for terra-cotta ware. At several other places the silt is used for tile. The presence of 1 juried soils at great depth which are underlain as well as overlain b\- till is a, not uncommon feature. In some cases the soils are COMPOSITE MORAINIO BELT OP NORTHERN ILLINOIS. 301 referred to the Peorian interglacial stage, for they probably occur at the junction of the Wisconsin and lowan drift sheets. But it is possible that in many cases they are of Sangamon age and occur at the junction of the lowan and Illinoian sheets. In the majority of cases they occur in the lower 23art of the drift. On the elevated portions they seldom are found at less than 125 feet from the surface, and in one instance (at Gilbert station) a soil wasfoujid at 180 feet. The drift on the elevated portions apparently averages not less than 200 feet. On the lower portions of the belt, in southern Kane County, the drift is correspondingly tliinner. The buried soil is found at much less depth, but at about the same elevation above tide as in the higher portion. The occurrence of the buried soil, its depth and its relation to other beds of the. drift, may be seen by reference to well sections of McHenry and Kane counties given on subsequent pages. As noted above, this portion of the composite belt abounds in knolls and short ridges which are composed largely of gravel. These are largest and most numerous along the inner slope adjacent to Fox River, but are found occasionally on the elevated parts of the moraine — for example, near the north line of Kane County. These ridges occur both singly and in groups. They are also arranged in chains or narrow belts. They present considerable variation in structure. The majority have but little till with the sand and gravel, but some present a large amount of till in the lower portion. This is especially true of those on the elevated portion of the moraine in northern Kane County. In several cases the knolls are found to have a body of coarse gravel and cobble at their summits which extends downward in a funnel-shaped mass toward the center of the hill. In other cases the central portion of the hill is composed of sand and the gravel and cobble is found in the peripheral portion. A knoll in sec. 14, T. 42, R 7 E., ojDened extensively for gravel, is found to contain alternations of till and assorted material. The till apparently forms a network of connections around lenticular masses of gravel. In most instances the gravel and cob- ble is found to extend scarcely as low as the base of the knolls. Borings have sometimes been made in the bottom of the gravel pits, and these usu- ally penetrate a considerable depth of oxidized till. Indeed, the oxidation appears to be fully as deep beneath these knolls as the average depth of surface oxidation outside the knolls. The bedding of the assorted material is seldom horizontal, but cm-ves and dips as if the material had been subject 302 THE ILLINOIS GLACIAL LOBE. to much disturbance after deposition. In this respect these knolls and ridges differ from the bedding usually displayed by eskers. Bowlders are found in moderate number over all parts of the moraine. They are especially abundant in a belt extending fi-oni Gilbert station north- ward to the vicinity of Crystal Lake. The belt is widest near the Kane- McHenrv county line, having there a width of about 4 miles. There is pi'obably signilicauce in the fact that this bowlder belt borders the head of the Kishwaukee gravel plain, which was an avenue of discharge for the glacial waters. The bowlders are usually crystalline rocks of Canadian derivation, but there are also present large limestone blocks, which in some cases will furnish several wagon loads of building- stone. These are especially abundant west of Elgin, and are found occasionally farther north, in both Kane and McHenry counties. They are apparentl}^ derived from the ledges of Lockport (Niagara) limestone, which underlie the disti'ict immediately to the east and probably extend into the district covered by this moraine. In some cases these large masses of limestone have led the residents to suppose that the rock is in situ and that extensive quarries might be opened by the removal of a slight amount of drift. The error of this interpretation has usually been discovered upon quarrying a few loads of stone. Wells west of Elgin, in the neighborhood of these limestone blocks, indicate that the drift there has an average thickness of more than 100 feet. Whether the sup]30sed limestone outcrop in eastern McHenry Count}", mentioned in the Greology of Illinois,^ is a ledge in situ or a transjjorted block similar to those just mentioned was not ascertained. CORRELATIONS. Satisfactory correlations of this portion of the composite belt with the more clearly differentiated moraines in the districts to the south have not yet been established. Two quite distinct interpretations have been suggested in the course of the investigation. By the first interpretation this portion of the composite belt is made to be the continuation of the inner part of the Bloomington morainic system, which connects with it near Elburn. The very strongly morainic tract immediately northeast of Elburu ^^'ould, in this case, be situated at a sharp bend or reentrant angle in the ice marg-iu, and ' Vol. IV, pp. 131, 132. COMPOSITE MORAINIC BELT OF NORTHERN ILLINOIS. 303 this may account for its greater ruggedness. The uiidulator}- tract leading southward from this sharply morainic portion might by this interpretation be accounted for as a spur extending backward from the sharp bend in the margin. The bulk of the Bloomington system is not greatly different from that of the composite belt west of Fox River and presents lao obstacles to this interpretation. The topography of the composite belt is much sharper in expression than that of the Bloomington system, but changes of topog- raphy have been found to occur in other belts to as marked a degree as in this instance. As pointed out by Chamberlin, in the Third Annual Report, the Kettle moraine changes from a very sharp knob-and-basin topography in southern Wisconsin to a comparatively smooth swell-and-sag topography in northeastern Illinois and northwestern Indiana, and again assumes a sharji knob-and-basin topography when traced into Michigan. By the second interpretation this portion of the composite belt is thrown into the late Wisconsin series of moraines and its continuation found in the bowlder belts and feebly developed morainic tracts lying outside the Valpa- raiso morainic system in Kane, Kendall, Grundy, and Kankakee counties. These belts can be traced into a reasonably close connection with tlie southern end of the undulatory belt in southern Kane County. Tliere seems to be, therefore, no formidable gap to bridge in making this corre- lation. The greatest obstacle to the interpretation appears to be found in the abrupt change in bulk which the moraine presents in the district east of Elburn. From this point southward a thickness of only 20 or 25 feet is presented by the moraine, where best developed, while to the north the thickness averages more than 100 feet. The expression also is much strono-er north than it is south from this line. Perhaps by combining these interpretations a solution may be found. The great bulk of the portion north from Elburn and the very strong- expression of the portion immediately northeast of Elburn may be a result of the invasion which formed tlie Bloomington morainic system. At the late Wisconsin invasion this region may have been partially overridden by the ice, but without greatly modifying- its appearance and without deposit- ing a greater amount of drift than is found in the gently undulatory belt in southern Kane County and the feeble moraines in the district to the south. In this case the gently undulating tract in southern Kane County may be largely the result of the late Wisconsin invasion, though the interpretation 304 THE ILLmOIS GLACIAL LOBE. that it is a spur from the reentrant angle in the Blooniington system need not be set aside. The Kaneville esker Hes mainly within the limits of this undulatory belt and seems to have been formed at as late a date. Its western end, together with the delta, extends beyond the line of the bowldery tracts referred to the late Wisconsin invasion. This fact seems to throw the bal- ance of evidence in favor of tlie correlation with the Bloomington system. Furthermore, the Kaneville esker seems to be a part of the series of g-ravelly knolls and ridges above mentioned which are developed along the inner border of the Bloomington morainic system in the district to the west. It is possible that chains of gravelly knolls and ridges which lead westward from Fox River Valley in northern Kane County into the higher portions of the moraine were formed at the same time as this esker and under similar conditions. The prominent knolls which occur in the midst of the gently undulating belt — Johnson's Mound, Ball Mound, and Washburn's JMound — mav also be included in the same categ'ory. They appear to be composed largely of gravel, though their structure is known only from two well sec- tions on their higher parts and slight excavations on their borders. PORTION OF COMPOSITE BELT EAST OF FOX RIVER. DISTRIBUTION AKD CONNECTIONS. From the ^dcinity of Elgin northward to the Wisconsin line the valley of Fox River alone separates a morainic tract on the east from one on the west side of the river, and throughout much of this interval the stream wnnds about through lakes and marshes among morainic knolls without forming a well-defined valley. Southward from Elgin the composite belt separates into distinct moraines, between Avhieh are plane tracts. One of these moraines, called the Valparaiso, swings around the head of Lake Michigan; another, called the Marseilles, follows nearly the east bluft' of Fox River south and west to the Illinois River. As already noted, a weak morainic system of late Wisconsin age leads southward, and the Bloomington system southwestward, from the ])ortion of the composite belt west of Fox River. The equivalency of the Valparaiso morainic system to the eastern portion of this composite belt is established beyond doubt. Probably it should include all uf the composite belt nortli of Elgin on the east side of COMPOSITE MOKAINIO BELT OF JS^ORTHEEN ILLINOIS. 305 Fox River, and possibly it also iu eludes a small part west of this stream. It may extend as far west as the east border of English Prairie, at the State line, and may embrace the tract between Fox River and Crystal Lake outlet, farther south. The equivalent of the Marseilles morainic system in this composite belt is not satisfactorily determined. From northern Kendall County north- ward it appears to have been overridden to some extent by a later advance of the ice, and is perhaps completely concealed by the later deposits within this composite belt. The portion of the composite belt east of Fox River has a width rang- ing from 6 or 7 miles at the State line to about 15 miles at the south line of Lake and McHenry counties. Between these lines it is mainly in Lake County, but includes a narrow strip in eastern McHenry County. From the south line of these counties southward to Elgin it lies mainly in Cook County, but includes the east border of northern Kane County and main- tains a width of 14 to 15 miles. This is about the width of the Valparaiso system farther south. GENEEAL FEATURES. The general elevation of this portion of the composite belt is lower than in the portion west of Fox River, being but little more than 800 feet above tide. The highest points are found in southern Lake and northwest- ern Cook counties, and they rise but little above 900 feet. One of these, just east of the village of Volo, stands 913 feet, and one in the northwest comer section of Cook County 910 feet, as determined by the barometric survey under Professor Rolfe. There are, however, but few other points rising above 850 feet. There is a well-defined ridge-like crest standing 20 to 40 feet higher than border tracts and having a width of about one-half mile which leads southward with a somewhat winding course through western Lake and northwestern Cook counties, forming the water parting between Fox and Des Plaines rivers. East from this crest line there are only gentle swells, seldom more than 15 feet in height, among which are occasional ponds and small lakes. This district presents a slope which descends eastward at the rate of 20 to 40 feet to the mile as far as the Des Plaines Valley. West from the crest line the surface is much more varied, there being tracts ."MON xxxviii 20 306 THE ILLINOIS GLACIAL LOBE. covering a few square miles in which a sharp knob-aud-basin topography is developed, around which are gently undulating tracts, such as occm- on the east slope. There are also extensive marshes west of this crest, and the drainage is generally less perfect than on the east slopes. Lakes abound in Lake County on both the west and the east slopes. They range in size from an area of several square miles down to an acre or less. They are usually bordered wholly or in part by knolls and ridges which rise 10 to 50 feet above their surface. In some cases extensive marshes border one or more sides of the lakes. These lakes, with their bordering hills dotted with groves, add greatly to the beauty of the scenery. The lakes and also basins become rare soiithward in Cook County. The few which occur are very small and shallow. THICKNESS OF DRIFT. Records of several deep boring-s were obtained which give an average thickness of about 200 feet of drift. Six borings failed to reach rock at an average depth of about 250 feet, one of them being 315 feet. As these borings are widely distributed, it seems probable that the general level of the rock surface is fully 200 feet below the drift sm-face. The underlying rock is limestone and presents a very uneven surface. The well borings indicate that vallej^s had been cut to depths of 200 feet or more prior to the di-ift deposition. Hence borings in the lines of these valleys, when located on high parts of the moraine, probably would encounter fully 400 feet of di'ift. The thickness of each of the several drift sheets here present has not been worked out so fully as in some other localities, but the drift of Wisconsin age apparently averages not less than 100 feet in depth, and may average 150 feet. STRUCTURE OF THE DRIFT. The upper portion of the drift to a depth of 100 to 150 feet consists mainly of till. The till is usually oxidized at surface to a depth of 10 or 15 feet, beneath which it presents a blue-gray color. It is also generally soft and fresh, and seems to be referable to the Wisconsin, though it may also include the lowau. At greater depths than 100 to 150 feet borings encounter either a hard gray till tinged with brown, probably Illinoian, or beds of sand and gravel, or an alternation of till with sand and gravel. Wells near Lake Zurich have in several instances encountered thick beds of THE MARSEILLES MOKAIIfE. 307 fine sand below the till, setting in at 100 to 140 feet and extending to 250 or 300 feet. At Barrington, and for several miles southwest, wells often enconnter a hard till at 100 to 160 feet which contains very little sand. In the vicinity of Ivanhoe and Wauconda wells pass thi-ough alternations of sand and gravel with hard till after leaving the sheet of soft till. In southern Lake and northwestern Cook counties the sheet of soft till is generally a poor source for strong wells, such as are required on dairy farms, though wells adequate for household use may usually be obtained at convenient depths. In the northern part of Lake County strong wells are often obtained without reaching the bottom of the Wisconsin drift sheet. The greater amount of sand and gravel found in the older di-ift sheets has led to the sinking of many weUs to these sheets at depths of 150 feet or more. Further data are given in the detailed discussion of wells. There are but few gravel knolls in either Lake County or Cook County, but such knolls are not rare on the borders of Fox River in eastern Kane and McHenry counties. Knolls composed mainly of till have in some cases pockets of gravel at or near the surface, which supply material for wagon roads. There are few localities west of the crest where gravel may not be conveniently obtained, but east of the crest it is not so well distiibuted. Surface bowlders occur in moderate numbers over all of tliis district. They are nearly all crystalline rocks of distant derivation, there being very few limestone or local rocks. The till is thickly set with limestone rocks as well as with those of distant derivation. SECTION V. THE MARSBIIiLES MOBAINE, DISTKIBUTION. This moraine next succeeds the Bloomington morainic system in the Wisconsin series. The name is taken from the village of Marseilles, situated at the point where the Illinois Eiver cuts thi-ough the moraine. The moraine is readily traced as far north as South Elgin, 4 miles south of the city of Elgin, where it is lost in the composite belt just dis- cussed. For about 25 miles south from South Elgin it is combined with a till ridge called the Minooka Ridge, and follows the east side of Fox River closely, past St. Charles, Greneva, Batavia, and Aurora, the eastern parts of 308 THE ILLINOIS GLACIAL LOBE. these cities occupying its outer face. There is usually but a single crest, and it follows nearh' the county line between Kane and Dupage. The width of the belt is 2 or 3 miles. The combined belt continues about 6 miles farther south than Aurora, along the line of Will and Kendall coun- ties, lea\4ug a strip 2 or 3 miles wide between the river and the moraine. The Marseilles moraine there swings abruptly westward, coming to the river bluff between Oswego and Yorkville, while the Minooka Ridge con- tinues southward to the head of the Illinois River. The Marseilles moraine follows neai'ly the southeast bluff of Fox River to the mouth of the stream, its outer border being nowhere more than 4 miles and usually less than 1 mile from the stream. The width in Kendall County is only 2 or 3 miles, but increases to 5 or 6 miles in northeastern Lasalle County, near the north bluff of the IlHnois River. At tlie Illinois Valley the moraine changes abruptly from a south- southwest to a south-southeast course. Its south-southeast course is mam- tained in a belt 3 to 5 miles wide passing tlu'ough southeastern Lasalle and northern Li^angston counties. In the latter county, as above noted, it is closely associated with Farm Ridge, a weak inner ridge of the Bloomington system. In the vicinity of Odell the moraine swings around eastward, and near the line of Livingston and Ford counties takes a course north of east, occupying in its curving portion a width of 8 or 10 miles. This course is maintained across northern Ford, northwestern Iroquois, and southern Kan- kakee counties, to the ^^cinity of Ste. Anne, where it changes to southeast. From northern Ford County to this point it has a width of 3 to 5 miles. The southeast com-se is maintained to the vicinity of the State line northeast of Donovan. Here this moraine meets the Iroquois, a moraine of the coalesced Erie-Saginaw lobe. Its relations to that moraine are still obscm-e, though the courses of the two moraines seem to be nearly coincident in Newton and Jasper counties, Indiana. Its width before connecting with that moraine is 1 to 2 miles. The combined moraine has a width of 3' to 6- miles and is traceable as far as Medaryville, in Pulaski County, Indiana, beyond which it seems either to die out or to be concealed beneath the "Lake Kankakee" sand rido-es. Possibly this combined moraine constitutes an interlobate belt, but, as indicated below (pp. 318, 327), it seems more probable that it is a result of two advances differing in date as well as direction. THE MARSEILLES MORAINE. 309 RANGE IN ALTITUDE. The Marseilles moraine displays very little range in altitude. The crest varies scarcely 25 feet from the 750-foot contour, and the lower parts of the moraine stand near the 650-foot contour. Tlu-oughout much of its course the 650-foot contour follows approximately the outer border of the moraine. The inner border is somewhat higher, but as a rule falls below 700 feet. RELIEF. The above statements concerning range in altitude may be readily applied in reference to the relief of the moraine. On the outer border it averages about 100 feet; it is seldom less than 50 feet and in places reaches 125 feet. The relief on this border is least in the northern and the eastern portion of the belt, in places being 50 feet or less. The middle portion, except where combined with the weak inner ridge of the Bloomington sys- tem (Farm Ridge), has a general relief of 75 to 100 feet or more. On the inner border the relief seldom exceeds 50 feet, and for a few miles at the north scarcely exceeds 25 feet. SURFACE CONTOURS. Throughout much of its course the Marseilles moraine has a well-defined crest, and this, as a rule, constitutes a water parting. North of the Illinois River it separates the tributaries of Fox River from those of Dupage River, Au Sable Creek, and Nettle Creek. South of the Illinois it separates trib- utaries of the Vermilion River from those of Mazon Creek and Kankakee River. In eastern Illinois, however, it does not constitute an important water parting, being crossed by the Iroquois River; and in western Indiana it is crossed by tributaries of that river. The crest is sharpest for a few miles in the central part of Kendall County, south and southwest of York- ville, where it presents a narrow ridge standing 30 to 40 feet or more above bordering portions of the moraine. Usually the crest is a broad, gently undulating ridge 1 or 2 miles in width. Along the crest, as well as on the slopes, there are saucer-like depressions containing water, except in seasons of drought, and often occupied by clumps of willows. The swells are usually low, seldom exceeding 20 feet in height, and have gentle slopes. However, in parts of Livingston County, southeast of Odell, the swells in some cases reach a height of 50 feet above sloughs inclosed among them. There is 310 THE ILLINOIS GLACIAL LOBE. also a group of prominent knolls in the ^-icinity of the line of Kankakee and Iroquois counties, south of Hersher. Some of these reach a height of about 75 feet. At the point where the course of the moraine changes from east of north to southeastward, near Ste. Anne, there is a -s-ery prominent gi'oup of knolls, called Mount Langum, standing 75 to 100 feet above bordering tracts on the north. These groups of prominent knolls have, however, a combined area of but a few square miles. Toward the inner border tlii-oughout the entire length of the moraine the swells gi-adually decrease in height and become less frequent, until they can not be distin- guished fi'om the gentle undulations of the till plain, which are commonly 5 or 6 feet in height. In a few places, aside from those noted above, a somewhat sharp knob-and-basin topography is developed. The most con- spicuous development is in Kendall County along the sharp crest, and this tj^e of topog-raphy is characteristic of much of the crest in that county. The knobs seldom exceed 25 feet in height; but as they cover only 2 or 3 acres each, they are much sharper than the majority of the knolls. The basins are shallow, saucer-like depressions. It is worthy of note that the portions of the moraine having sharpest expression are usuallv covered with forest. Possibly the protection afforded b}^ forest growth is partiallv responsible for the sharper contours, but it seems liardly probable that the difference in contour in forest and prairie can be entu-ely due to this protection. The outer margin of the moraine often extends out in spur-like pro- jections a mile or more beyond a regular border, and usually where streams emerge the margin is indented an equal or even greater amount. These spurs slope down much less abruptly from the morainic crest than the tracts between them, thus giving the appearance of low ridges running out from the crest nearly at right angles to its course. The indentations at the places where streams emerge are not referable to erosion by the present streams, but are in all probability due to the removal of material by streams issuing from the ice sheet. There are occasional breaks or uaiTOw gaps interrupting the crest. One about 4 miles east of Yorkville, about 75 feet in depth and one-foui-th to one-half mile in width, passes entirely acro.ss the moraine, permitting di-ainage from the inner-border plain to pass through the moraine to Fox River. Another gap fully as lai-ge is found in tlie southwest corner of THE MAESEILLES MORAINE. 3n Kendall County and is represented on the Marseilles topographic sheet. A water parting occurs in this valley-Hke gap at the inner border of the moraine near the line of Grundy and Kendall counties. It stands only 640 feet above tide, while neighboring portions of the moraine on the north and west are about 100 feet higher. About 6 miles southwest from this gap there is a shallower one in which the water parting is 690 feet, or 40 to 60 feet below neighboring portions of the morainic crest. At the Illinois Valley the moraine is interrupted by a^ gap about 1^ miles in width. It stands 675 to 700 feet above tide at the south bluif and 650 to 675 feet at the nofth bluff. The broad bottom of the valley stands only about 600 feet; but this, as shown below, has been lowered by the "Chicago Outlet." These gaps, like the indentations, seem referable to streams issuing from the ice sheet during the formation of the moraine, and perhaps also during the withdrawal of the ice from the plain on the east. In eastern Livingston and northern Ford counties the main ridge lies near the north border of the belt. Outside of it, extending nearly to the east fork of Vermilion River (a distance of about 6 miles), there is an undulatory tract probably of morainic character. The surface of much of this tract is fully as undulatory as on the main part of the moraine, and stands nearly as high as the crest of the moraine. Plane tracts one-half mile to a mile or more in width and 25 to 40 feet in depth extend north from the east fork of Vermilion River nearly to the crest of the moraine, greatly interrupting the contiimity of the undulatory tract just noted and giving the appearance of spurs leading out to the south. There is, however, at the east a well-defined crest in this outer belt with a trend approximately parallel with that of the main crest. This suggests the interpretation that the moraine consists of a double ridge in this region, and that its outer ridge has been imperfectly developed or greatly eroded. If the imperfection is due to erosion, it seems necessary to restrict the eroding agency chiefly to water escaping from the ice sheet, for there has been apparently but httle postglacial erosion in this locality. THICKNESS OP THE DRIFT. The thickness of the drift along the Marseilles moraine has a known range from less than 100 feet up to 360 feet. In eastern Kane and western Dupage counties the thickness along the crest is generall}- 100 to 150 feet. 312 THE ILLINOIS GLACIAL LOBE. Ill Kendall County it has a known range from 100 feet to fnlly 200 feet. In Lasalle County the well records show a range from about 100 up to 285 feet. In Li%angston County the range is still greater, the distance to rock varying from 100 to 360 feet. Along the line of Kankakee and Iroquois counties it deci'eases from about 160 feet at the west to only 60 feet at Ste. Anne, but wells between Ste. Anne and the State line penetrate 80 to 150 feet of drift. The greater part of the drift? appears to be referable to the Wisconsin drift sheets. The older sheets are seldom entered at less than 100 feet along the crest of the moraine, and in some wells a fresh-looking drift (Wisconsin) is reported to extend to a depth of 160 feet. The diift refer- able to the invasion which formed the Marseilles moraine probably about equals in thickness the measure of the relief of the moraine, which, as noted above, is 50 to 125 feet. STRUCTURE OF THE DRIFT. The Marseilles moraine consists mainly of a sheet of blue till which contains only a moderate amount of coarse rock materials. A few low gravelly knolls occur in some of the recesses on the outer border of the moraine in Kane, Kendall, and northern Lasalle counties. The sharp knolls south of Hersher, and the prominent group of knolls known as j\Iount Laugum, near Ste. Anne, are composed largely of gravelly material. These constitute the chief instances of the occun-ence of gravelly knolls along the entire length of the belt. There are often small pockets or thin beds of sand and gravel inclosed in the sheet of till, which afford a supply of water for the shallow wells. These seldom afford a sufHcient amount of water for dairying or stock raising, the supply for these purposes being obtained either from the older sheets of drift or from the imderl)-ing rock. This moraine carries very few sui-face bowlders, there being scarcely enough to supply the needs of the residents for foundations of buildings and construction of Ijridge culverts. In one locality, however, east of Yorkville, the moraine is crossed by a bowlder belt which apparently pertains to a later advance of the ice, since the bowlder belt does not follow the moraine but passes southward across the inner-border plain, as indicated later (pp. 325-326). THE MARSEILLES MOEAINE. 313 The depth of surface oxidation in tliis moraine is less than on any other moraine of the Wisconsin series within the area under discussion. In Liv- ingston County the blue till is commonly entered at 4 to 6 feet, and in places at even less depth. The oxidized till, therefore, has scarcely half •the depth usually found in the Wisconsin drift sheets. The slight depth of surface oxidation is probably attributable to the compactness of the till, which is nearly impervious to water. It can not be attributed to flatness of surface, because the depth of oxidation is found to be very slight on undulating as well as level portions of this drift sheet. The sections of many wells obtained along this moraine and on the inner border are presented in the discussion of wells (Chapter XIV) in the counties traversed by the moraine. These serve to indicate the gi'eat preponderance of till over assorted material in the portion of the drift referable to the Marseilles moraine. They also serve to indicate the rela- tive proportions of" till and assorted material in the sheets of older drift imderlying the Marseilles and other Wisconsin drift sheets. CHARACTEE OF THE OTJTWASH. Along Fox River, in Kane and Kendall counties, just outside the Mar- seilles moraine, there is a belt of coarse gravel. In places the deposit lies mainly on the same side of the river as the moraine, but generally it is on the opposite side. At Batavia it is chiefly on the west side, at Aurora on the east side, and at Yorkville on the west side. At Millbrook and at Mill- ington the larger part of the gravel is on the east side of the river. The belt of gravel extends but a short distance below Millington, the valley below that point being cut in till and rock strata. The origin of this belt of gravel has not been decided. Possibly it is referable to the invasion which formed the Marseilles moraine, but quite as probably it should be referred to the later advances of the ice sheet, during which the Marseilles moraine was partially ovei-ridden. The gravel is so extensive in Kane and Kendall counties and so small in amount farther down Fox River as to sua-- gest the interpretation that it forms an extensive delta in northern Kendall and southern Kane counties, and that free drainage or escape of the waters down Fox River had not been established. In the vicinity of the Illinois River there ai-e indications of a lake-like expansion of outflowing waters whose borders are found. iu the sand ridges 314 THE ILLINOIS GLACIAL LOBE. discussed on a preceding page (p. 288). The Illinois Valley, therefore, appears to have been unopened along the section between the Marseilles moraine and the inner moraine of the Bloomington series. In eastern Illinois the basin now drained by the Iroquois River north- ward to the Kankakee would have been prevented from discharging in this direction by the ice sheet. It is probable, as noted above, that the outlet from this district was westward across the rim of the basin in northern Ford County to the east fork of Vermilion River. As this rim stands somewhat higher than the northern part of the basin, it may be supposed that the ice sheet terminated in a shallow body of water. The only outwash found along the outer borders of the moraine in this district consists of tine sand and silt forming a thin coating on the surface of the till. ^'^Hiether this is an outwash from the ice at the time of the formation of the ]\Iarseilles moraine or is of later date can scarcely be determined in the present stage of investigation. Studies in western Indiana indicate that a lake may have occupied this region for some time subsequent to the retreat of the ice from the Marseilles moraine, and this silt-and-sand deposit may be a product of the later stage of the lake. In eastern Livingston County there may have been a fair escape for the water southward into the East Fork of Vermilion, though this is not fully demonstrated. Reviewing the above statements, it appears that, with the possible exception of the northern portion of the moraine in Kane and northern Kendall counties, the ice sheet was bordered extensively by lakes, which prevented a vigorous outwash. But these lakes were so shallow as to inter- fere in no way with the building up of a bulky moraine. They seem also to have allowed the waters escaping from the ice sheet to form the gaps and indentations in the moraine, noted above. If these were formed either by water escaping from the ice while it overhung the ridg-e, or at a later date from a lake held on the east side of the ridge (the only probable agen- cies yet recognized), the existence of lakes in the outer border district may seem questionable. This seeming incompatibility may perhaps be explained by assuming that a submarginal glacial stream had accumulated sufficient hydrostatic pressure to carry a strong current into the extra-marginal lakes. THE MAESEILLES MOEAIS^E. 315 INNER-BORDER TILL PLAIN. On the inner border of the Marseilles moraine fit'om northern Kendall County, where it separates from the Minooka Ridge, southward through Grundj and adjoining portions of Lasalle and Livingston counties, and thence eastward through Kankakee County, there is a till plain which shows a perceptible descent away from and nearly at right angles to the moraine. As the moraine describes nearly a half circle in this interval, the sloping plain converges toward a focal point, which is located near the head of the Illinois River. There is a similar descent toward the head of the Illinois from the east ; thus a basin is formed, which is commonly known as the Morris Basin, fi-om the city of Morris, which stands near its central portion. The slopes of this plain are well shown by the direction, of drain- age lines, which converge from all quarters toward the head of the Illinois River. (See topographic map, PL III.) At present the basin is deeply notched at its western border by the valley of the Illinois River, but at the withdrawal of the ice sheet tlie e"\ddeuce is quite clear that the western rim stood sufficiently high to hold a lake of considerable size in the Morris Basin. The history of this lake is discussed in some detail below. On the border of this till plain next to the moraine the surface is gently undulating, but within a few miles it become an almost expression- less plain. In Kankakee, southwestern Will, and eastern Grundy counties the plain is occupied by sand dunes and beaches ; elsewhere it is generally veiy smooth. There are, however, a few points in southeastern Kendall and northeastern Grrundy counties where the di-ift is slightly ridged. In the vicinity of Lisbon, in southern Kendall County, the drift is insufficient to conceal the inequalities of the limestone ridges, but the surface is only gently rolling, the crests of the ridges being scarcely more than 20 feet above the sags. This area is 2 to 2 J miles from north to south and 5 to 6 miles from east to west, and lies mainly in the south half of T. 35, R. 7 E. The drift along the border of the Marseilles moraine has generally a thickness of 100 feet or more, but upon descending- the slope toward the head of the Illinois the thickness decreases, and there are extensive areas in eastern Grundy, southwestern Will, and northern Kankakee counties where rock is encountered at very slight depth, so that the shallow ravines 316 THE ILLINOIS GLACIAL LOBE. and shallow wells and even the cellar bottoms reach it. The drift appears to be composed mainly of till and differs in no essential degree from that found in the Marseilles moraine. The j^ellow or oxidized till at surface is apparently somewhat thicker than on the moraine. At the surface there are extensive deposits of sand and silt occun-ing up to an altitude of nearly 650 feet, though most abundant at 575 feet or less, which in all probability are referable to the lake that occupied the basin. These deposits in some places reach considerable depth and are either accumulated in knolls and ndges or spread evenly over the surface. In other places they are insuffi- cient to conceal the surface bowlders. In the greater part of this district wells may be obtained at a depth of 25 feet or less. In some cases they are obtained at the base of the sui-face sand; in others near the junction of the yellow and blue tills, there being not infrequently thin beds of sand and gravel at that horizon; in still other cases they enter the blue till. Several flowing wells have been obtained from the di'ift. These are discussed in connection with other wells, in the detailed discussion of wells given in Chapter XIV. CHAPTER X. THE LATE WISCONSIN DRIFT SHEETS. BASIS FOR SEPARATION FROM THE EARLV WISCOXSIK. The necessity for sepai^ating the moraines of this later drift into two series was brought out by Chamberhn's early studies in eastern Illinois and western Indiana. He discovered that the very bowldery morainic belts of Benton and Warren counties, Indiana, pass directly across the line of the earlier moraines which lead up to them from the west. The fact was also noted that the earlier series of moraines are not markedly older than the later series. In view of this freshness of the drift of the earlier series and of certain obscure tracts in the Kankakee Basin, he makes the following statement:^ The drift of this area [Kankakee Basin] bears undoubted evidence of being- recent, and, though this is in considerable part due, superficially, to aqueous agencies, it seems to me probable that the region will prove to have been largely, possiblj' com- pletely, covered by ice iu the earliest stage of the second glacial epoch. It is not, however, traversed by conspicuous moraines, at least not by any as well developed as those outlined. Low-ridged belts of subdued morainic aspect have been observed at numerous points, but their relations have not yet been traced ont. A similar qualifying remark may here be made concerning a considerable area in northern Illinois, outside the moraine described in this paper. The freshness of its drift and the nnsculptured contour of its surface bear evidence of recent origin. Subsequent studies by Chamberlin and liis associates have brought out more clearly the evidence that the bowldery moraines are out of harmony in trend with the moraines of the early Wisconsin series. Thej^ have also shown that the bowldery moraines present a somewhat fresher surface con- tour than the moraines overridden by them. It is upon the basis of these differences in trend and in freshness of contour that the removal from the early Wisconsin has been made. As yet no soil or leached or weathered zone has been found separatmg the drift of the- two series, and it still seems ■ Third Annual Report U. S. Geol. Survey, p. 331. 317 318 THE ILLINOIS GLACIAL LOBE. questionable whether the interval between their deposition was sufficiently long to justify" their reference to distinct glacial stages. The shifting of the ice lobes, however, is thought to indicate a retreat of some consequence between the two ice advances — a retreat probably much greater than took place between the formation of neighboring- moraines of the early Wis- consin series. OUTLII^B OF THE I.ATE WISCONSIIST BORDER. So far as is yet known, the oldest moraine of the late Wisconsin series is the Iroquois moraine of the coalesced Erie-Saginaw lobe. Full correla- tions, however, have not been made of moraines of this series in the several ice lobes. This moraine appears in northwestern Pulaski County, Indiana, in the midst of the sand area known as "Old Lake Kankakee," and leads southwestward along the divide between the Iroquois and Kankakee rivers, across Jasper and Newton counties, Indiana, to eastern Iroquois County, Illinois. It there swings abruptly southward, crossing the Iroquois River between the State line and Watseka, Illinois, and soon curves to the so"utheast, reentering Indiana in northwestern Benton County. It thence passes soiitheastward across Benton and Warren counties, coming to the Wabash Valley at Williamsjiort. Its further continuation to the southeast is indicated approximately on the map accompanying Professor Chamberlin's paper in the Third Annual Report. The moraine is discussed in detail in a report now in preparation, which embraces the moraines of the Erie lobe. From the point Avhere the Iroquois moraine turns southward in eastern Iroquois County, Illinois, a bowldery belt leads northwestward past Ste. Anne to the Kankakee River just above the city of Kankakee, being closely associated with the Marseilles moraine to that point, but apparentl)^ distinct from it at points farther north and west. This belt is discussed below as a possible correlative of the Iroquois moraine. By this interpretation the moraine occupying the divide between the Iroquois and Kankakee rivers in Newton and Jasper counties, Indiana, is interlobate in character. This interpretation would furnish an explanation for the abrupt eastern termina- tion of the moraine, there being a coalescence of the lobes so complete in the eastern part of the Kankakee Basin that no moraine was formed. Unfortunately, tlae features are somewhat vague in the district northwest from the ])oint where the Iroquois moraine turns soutli and the interpretation THE MINOOKA TILL EIDGE. 319 is not entirely be5^ond question. There seem, however, sufficient grounds for referring certain featm-es in that region provisionally to the late Wiscon- sin deposits. These features are of two classes, namely, bowlder belts and ridged drift. These are discussed separately, since their association is not sufficiently close to make it certain that they represent a single ice advance. As indicated below, the ridging (discussed under the head "Minooka Till Ridge") may have preceded rather than accompanied the deposition of the bowlders. SECTION I. THE MI3\^OOKA TIIiL KIDGE. DISTRIBUTION. This till ridge receives its name from the village of Minooka, in north- eastern Grrundy County, which is situated on its crest. As noted above, it is united with the Marseilles moraine in Kane County, and being smaller than that moraine its discrimination may be made with difficulty. In the northeast part of Kendall County it leaves the Marseilles moraine and takes a southward course along the county line between Kendall and Will and Grrundy and Will counties to the head of the Illinois River. The crest as a rule lies in the eastern tier of sections in Kendall and Grundy counties, but in places touches western Will County. The width of the ridge, includ- ing both slopes, is scarcely 2 miles. It consists of a single smooth ridge on whose crest and slopes there are few swells exceeding 10 feet in height. The ridge is crossed by two valley-like depressions -which unite near its western edge in sec. 13, T. 36, R. 8 E., and drain west into Au Sable Creek. These are cut down to the level of the plain on the east side of the ridge. They apparently were formed by the discharge of water from the ice margin or ponded between the ridge and the receding ice front. PROBABLE LINE OP CONTINUATION. Up the Kankakee River, from the head of the Illinois nearly to the State line, there is an occasional development of low di-ift ridges and gentle swells on the north side of the valley. On that side of the river, 1 to 3 miles back from the stream, there is an abrupt bluff-like rise of 25 to 50 feet, and the ridges and swells front this bluff or lie immediately back of it. This system of ridges and swells nearly everywhere stands slightly higher than the plain which lies to the north. In the vicinity of Kankakee this 320 THE ILLINOIS GLACIAL LOBE. ridged belt borders the river quite closely and part of the city stands on it. From that city it takes a course slightly north of east to Exline, cutting across the great bend in the river opposite the mouth of the Iroquois River. Some uncertainty is felt as to its continuation from this point. It ma^- continue eastward into Indiana parallel to the river and pass beneath the Valparaiso moraine, though it seems quite as probable that it finds its con- tinuation in the belt leading southeast from Mount Langum, above described (see Marseilles moraine). The break opposite Mount Langum is merely the width of the Kankakee Valley, scarcely 2 miles. No similar ridging occurs on the south side of the river in western Kankakee or in Will County. There is instead a gradual rise from the low bank of the river southward through a sand-covered disti-ict to the till plain which lies inside the Marseilles moraine. The greater accumulation of drift on the north side of the river, taken in connection with the occasional development of moraine-like features, apparently supports the interpretation thus made — that the continuation of the Minooka till ridge may be found along this line. BELIEF. The southern end of the well-defined Minooka Ridge (at the head of the Illinois River) stands 100 to 110 feet above the Illinois River. The general relief of this ridge above the plain which borders it on the west is 50 to 70 feet. The profile of the Chicago, Rock Island and Pacific Rail- road, which crosses the ridge at Minooka, shows a relief on the west side of about 65 feet. The relief is slightly less on the east and is also less abrupt than on the west. The bluff-like ridge along the Kankakee, where best developed, stands but 30 to 40 feet above the plains on the north, and its usual relief on that side is only 10 to 20 feet. On the side next the Kankakee there is a gen- eral relief of 30 feet or more, with occasional points where it exceeds 50 feet. Evidently a portion of this relief is due to stream erosion, but the excavation is so shallow that the stream is responsible for scarcely 20 feet of the relief THICKNESS OF DRIFT. Beneath the crest of the Minooka Ridge, from the head of the Illinois northward, the drift is shown by wells to be 130 to 150 feet and in one THE MINOOKA TILL EIDGE, 321 instance nearly 200 feet in thickness, the thickness as compared with that on bordering j^lains being about as much greater as the measure of the relief of the ridge. In the portion along the Kankakee the thickness seldom exceeds 60 feet, but is g-reater along the higher parts than on the lower or than on the border plain, as would be expected from the relief which it presents. STRUCTURE OF DRIFT. In the ridge north from the head of the Illinois the surface portion of the drift to a depth of 8 to 12 feet consists of a yellow till containing many pebbles. It is sandy in places, but as a rule is a stiff, sticky clay, very slowly pervious to water. This yellow till is imderlain by a grayish blue till containing occasional gravel or sand veins, which furnish water in small quantities. This bed of till often has a thickness of 100 feet or more. Beneath it there is in places a heavy deposit of sand. This may not underlie the whole of the ridge, but has been penetrated in several wells along the crest in Kendall County. It furnishes abundance of water for wells. The ridge from Minooka northward carries a black surface soil several inches in depth, such as is found on the bordering plains. There are few surface boAvlders, and pebbles are rare within 18 inches of the surface. The drift along the north border of the Kankakee is mainly till, and sui-face bowlders are more abundant than in the portion north of the head of the Illinois River. CHARACTER OF THE OUTWASH. The well-defined portion of the Minooka Ridge has a low part of the Morris Basin on its outer border. Unless the outlet down the Illinois had been opened to a level as low as this part of the basin, the basin would have held a lake, and there scarcely could have been vigorous discharge ft'om the Minooka Ridge. Terraces on the Des Plaines River which have their head in the Valparaiso moraine and were formed in connection with that moraine indicate that a lake stood in this basin at the head of the Illinois while they were forming and that its level was about 560 feet above tide, or 60 feet above the present head of the Illinois River. This lake level is well defined also by beaches which are to be seen both north and south of the Illinois. MON xxxviii 21 322 THE ILLINOIS GLACIAL LOBE. Such being- the case at the time tlie Valparaiso moraine was forming-, it fol- lows that at the time the Minooka Ridge was formed the lake stood fully as high, if not higher, for the Minooka Ridge antedated the the Valparaiso moraine in its formation. The low part of the basin immediately west of the Minooka Ridge stands only a few feet above the level of the beaches referred to and would apparently have been extensively inundated during- the melting- of the ice sheet, even if the outlet from the Morris Basin liad been cut down to the level of the well-defined beach bordering the Illinois River. A vigorous discharge of waters across the basin could scarcely be expected. Certain features which suggest vigorous discharge Avill next be considered. The channels noted above, which cross the ridge a few miles north of the head of the Illinois, seem to have been made by a stream with a current having- considerable ^'olume, if not considerable strength. They are cut down to a gradient too low to give the present small stream which drains them a good gradient, and are consequently occupied by marshes. The conditions under which they were formed were probabh' similar to those wliich caused the gaps in the Marseilles moraine discussed above (pp 310, 314). A thin coating of sand is found in the portion of the basin immedi- ately west and south of these channels, a featui'e which implies current actioii, but perhaps no stronger than is consistent with the presence of a lake or ver)- broad lake-like stream. On the whole, the evidence seems insufficient to establish the existence of good drainage conditions. Turning to the Kankakee for light as to drainage conditions accom- pan5ang the formation of the ridge on its north border, it is found that sand deposits occur along the opposite side of the valley, forming- a much more conspicuous feature than on the west border of the Minooka Ridge. The deposits extend back usually 3 or 4 miles from the jiresent stream and reach an elevation fully as higli as the ridge on the north side of the valley. They have been drifted in places into prominent dunes. This sand may be interpreted either as the direct outwash from the ice at the time the ridged belt north t)f the \^alley was in process of formation, or it may seem refer- able to subsequent stream transportation, for the Kankakee Valley ^^■as the line of discharge for glacial sf reams issuing- from the Saginaw lobe during the ])erio(l (■inl)riic(M| in tlic I'onnation of two or more strong moraines, and IVimi :i piii-t of llic Laki' Miclii'^-nii lol)!' ilin-iun' tlie formation of the Val- THE MINOOKA TILL EIDGE. 323 paraiso moraine. These glacial streams had a current sufficiently strong to excavate a channel throughout nearly the entire length of the Kankakee Basin, whose north bluff may still be seen rising 15 to 30 feet above the Kankakee marsh. A current of this strength would seem to be entirely adequate to cause the transportation of such sand, deposits as are found on the lower course of the Kankakee. It may be questioned, therefore, whether these deposits may be referred with certainty to streams issuing from the ice sheet at the time the I\Iinooka Ridge was in process of forma- tion. The evidence here, as in the case of the channels north of the Illinois Valley, is scarcely sufficient to establish the occurrence of good drainage conditions at that time. The peculiar association of this sand belt with a bowlder belt is discussed below (p. 326). Inasmuch as the Iroquois moraine appears to have been formed either contemporaneously with or subsequent to the Minooka Ridge, the character of its outwash may be found serviceable in drawing conclusions concerning the outwash from the Minooka Ridge. On the outer border of the Iroquois moraine in Iroquois County, Illi- nois, and also in Benton County, Indiana, the outwash is a fine sand which has been transported to the lower parts of the Iroquois Basm and down the valley of Sugar Creek, a southern tributary of the Iroquois. As this out- wash is in a district lying outside the line of discharge for the glacial streams which traverse the Kankakee Valley, it is less difficult to interpret than the sands of the lower Kankakee. Its position is such as to be favor- able for discharge of water if no lake were present, since there is a descent away from the outer border of the moraine. Yet the fineness of the mate- rial seems to indicate that very imperfect drainage conditions attended the deposition of this moraine. The feebleness of discharge is thought to indicate that lake-like conditions may still have persisted not only in the Morris Basin but also in the Kankakee and Iroquois basins. On the outer border of the combined Marseilles and Minooka moraines, in northern Kendall and southern Kane cou,nties, there is an extensive gravelly plain, to which attention was called in connection with the Mar- seilles moraine. This plain has not as yet been definiteh' connected with anj'- of the moraines of the late Wisconsin series. Three means of deposi- tion need to be - considered, as follows: (1) By streams flowing down the. Fox River Valley during the formation of the Valparaiso moraine and 324 THE ILLINOIS GLAGIAL LOBE. spreading out a delta similar to that i'onned in the lower part (if the Des Plaines Valley by streams issuing from the same moraine; (2) by streams issuing from the ice at the time the Minooka Ridge was forming, for the ice at that time seems to have extended as far, at least, as the western edge of the Marseilles moraine in Kane County; (3) b}^ outwash from the Marseilles moraine, which sweeps around the eastern and southern border of the plain. In the present state of knowledge it seems difficult to draw inferences con- cerning the date at which this plain was formed,' and also concerning the broader question of the character of the outwash from the ice sheet during the Minooka substage of glaciation. Whether the Minooka Ridge is to be included in the late Wisconsin series can not perhaps be decided at the present stage of investigation. If it can be clearly established that during the interval between the formation of the Marseilles moraine and the Minooka Ridge the outlet down the Illinois had been lowered from about 640 feet above tide (the level of ueig'hboring outlets through the Marseilles moraine) to a level nearly as low as the 560-foot beach bordering the Illinois in the Morris Basin, a corre- spondingly late date for that ridge may be assumed. But at present there is much uncertainty as to the amount of work accomplished by that outlet prior to the formation of the Minooka till ridge. The bearing of bowlder belts on this question is considered below (p. 327.) INNER-BORDER TILL PLAIN. On the inner border of the Minooka Ridge, from the ^'icinity of Elgin southward to the head of the Illinois, there is a narrow till plain nowhere more than 6 miles, and usually but 2 or 3 miles, in width, which separates this till ridge from the Valparaiso morainic system. North from Elgin the Minooka Ridge has not been separated from the Valparaiso system. From the head of the Illinois eastward along the north side of the Kankakee Val- ley there is a similar till plain separating the ridged drift on the border of the valley from the Valparaiso morainic system. Its width is gretitest on the meridian of Kankakee, where it is fully 12 miles, the usual width being only 7 or 8 miles. East from Kankakee the till plain north of the river decreases in width and extends only a short distance east of the State line. The Valparaiso system there comes to the boi'der of the Kankakee marsh. BOWLDER BELTS. 325 An extensive sand-covered tract south of tlie Kankakee, in western Indiana and the east border of Illinois, is discussed below. The portion of the till plain north of the head of the Illinois shows usually a perceptible descent away from the Minooka Ridge, accompanied by a corresponding decrease in the thickness of the drift. On the borders of the ridge the drift is 100 feet or more in average depth, while at the east border of the till plain next to the Valparaiso system it is in places but 20 to 30 feet in depth. The drift appears to be mainly soft till, referable to the Wisconsin sheets. In places it is gravelly or sandy at base. The portion of the till plain north of the Kankakee in general rises slightly toward the north. The di'ift is apparently only 30 to 40 feet in average depth. In places rock ridges which carry scarcely any drift rise slightly above the general level of the plain. Siich ridges may be seen near Manteno. The drift is apparently nearly all Wisconsin. A few instances of the penetration of a buried soil in wells were reported from the north- east part of Kankakee County. This soil is within a few feet of the bottom of the a'lacial drift. The drift north of the Kankakee contains much sand and gravel, but there is usually a capping' of till a few feet in depth. The well sections of Will and Kankakee counties, presented in the latter part of this report, will set forth the variations in the structure and the thickness of the drift. SECTION II. BOWLDER BELTS. The Marseilles moraine and also the Minooka Ridge, as already indi- cated, carry a very few^ bowlders on the surface. Bowlders are also com- paratively rare on the inner or eastern slope of these ridges and on the till plain between the Kankakee River and the Valparaiso moraine. There is, however, a strip on the borders of the sand area along the south side of the Kankakee in Kankakee and Will counties, and in places within the sand area, where bowlders abound. This belt may connect on the southeast with the Iroquois moraine, though the connection is rather obscure because of sand accumulations. It appears to find a continuation northwestward in Grundy County along the borders of Mazon Creek, from the vicinity of Gardner to the mouth of the stream near Morris. From Morris a belt of bowlders extends northward 3 or 4 miles, beyond which, for about 6 miles, they are comparatively rare. Near Plattville a narrow belt sets in, 326 THE ILLINOIS GLACIAL LOBE. ■^lieli leads northward to the Marseilles moraine and passes over that moraine, as already noted, in the vicinity of the valley-like gap east of Yorkville. The bowlders occupy the gap and also the portion of the moraine to the east. To the north from this point the broad gravel plain along Fox River interrupts the belt for a space of 3 or 4 miles, but at the north border of this gravel plain bowlders again become numerous and abound along the west side of Fox River throughout the interval between this gravel plain and the composite belt of moraines above described. The boAvlders are unevenly distributed, there being small tracts and narrow strips where they are so numerous as to constitute a serious obstruction to the cultivation of the soil, occasionally numbering several hundi-ed per acre, but throughout most of the belts there are only a few per acre. The belt taken as a whole probabh' carries ten times the number of bowlders found in neighboring districts. The sand along the south border of the Kankakee is usually so heavy that the .bowlders, if present, would be obscured. In places where the sand is thin, bowlders are usually abundant. These oasis-like tracts in the midst of the sand area are in some cases difficult to account for. The heaping of the sand into ridg'es is probably due, in part at least, to wind action, and the wind may also have been influential in sweeping- the sand away from parts of the surface. It seems well, however, to introduce an alternative or supplementary explanation, though the applicability has not been fully tested. By the alternative interpretation a causal relationship is suggested between the occurrence of Ijowlders and the absence of sand, and the explanation found in the persistence of ice where the bowlders occur until the sand had accumulated in practicall}- its present depth and topography. Thi^ alternative explanation would also make the ridging of the sand partly the result of glacial molding which has been intensified by subsequent seolian action. This interpretation has been suggested by featm-es found in the old Lake Kankakee district, discussed below. It should perhaps be stated that the bowlders here or elsewhere in the belt can scarcely be considered a residue from erosion of the till, for they often occur on ])lains where tliere has been scarcely any opportunity for erosion. Furtliermore, they differ in constitution from the coarse rocks of the till, being almost wholly of crvstalline rocks of distant derivation, while th(.' till abounds in local rock fragments, Ixith coai'se and fine. BOWLDEE BELTS. 327 It seeiTQS more probable that the belt marks the position of the ice margin at some stage of advance between the formation of the Marseilles and Valparaiso moraines. Were the belt accompanied thronghont bv a moraine, or even a thin sheet of drift, this interpretation would seem well supported. For a few miles in the vicinity of the point where it crosses the Marseilles moraine there are low knolls accompanying the bowlders which may prove to be of the same date as the bowlder deposition. They are much smaller than the swells on the Marseilles moraine, being usualh^ only 3 to 6 feet in height and covering a few square rods each. They inclose shallow saucer-like depressions, and on the whole give the surface a fresher contour than is presented by the portion of the Marseilles moraine to the west. The portion of the belt from Morris northward was made a subject of joint investigation by Professor Chamberlin and the writer, and to each of us the surface contours appeared somewhat fresher along the line of the bowlder belt than in the district to the west. But the development of a new or distinct topography in connection with the bowlder belt seems at best to be limited to the immediate vicinity of the Marseilles moraine, and leads us to feel some doubt concerning the interpretation of the occur- rence of a thin sheet of di'ift in connection with the bowlder belt- It will be observed that the course of this bowldery strip is nearly parallel with the Minooka Ridge and its supposed eastern continuation along the Kankakee. This parallelism has suggested the interpretation that the bowlder belt may be closely related to that ridge Possibly there was a temporary advance of the ice beyond the position it held while forming the ridge, or possibly the accumulation of the bowlders and the ridffe occurred at the same time, the former being at the extreme margin and the latter a short distance back from the margin. The smoothness of the ridp'e apparently favors the interpretation that it is a submarginal accumulation. Another interpretation refers the formation of the bowldery strip to an advance subsequent to the formation of the Minooka Ridge. In that case the smoothness of the ridge may be due to its having been overridden. It seems highly probable that this bowldery strip is to be correlated with the Iroquois moraine and associated bowlder belts found in Iroquois County, Illinois, and Benton and Warren counties, Indiana, which are referred to the late Wisconsin invasion; The indefiniteness of the bowldery strip in the sandy districts of eastern Kankakee and northeastern Iroquois 328 THE ILLI]S"OIS GLACIAL LOBE. counties prevents a full and satisfactory- correlation. But notliing to oppose the con-elation has yet been discovered. At present it seems necessary to leave luisettled both its relation to the Iroquois moraine and to Minooka Ridge. SECTIOX III. X,AKE KAXKAKEE. Nearlv tlairty years ago Mr. F. H. Bradley applied the name Lake Kan- kakee to a body of water which he thought formerly occupied a large part of the Kankakee di-ainage basin.^ The existence of a lake in this region was suggested bv the occun'ence of deposits of sand outside the limits of the present Kankakee marsh. Mr. Bradley recognized the influence of wind in distiibuting sand over areas not covered by the lake, but considered the evidence satisfactory that along the line of the Louisville, New Albany and Chicago Railroad lake water had reached an elevation about 685 feet above tide. He had not full opportunity to explore the region; hence liis outline of the extent of the lake is rather indefinite. Chamberlin touched briefly upon this sand area in his paper in the Third Annual Report, as follows :' These dunes are a portion of a somewhat extensive tract, or i^erhaps rather a series of tracts, in northwestern Indiana, the precise distribution and origin of which are yet undetermined. They lie mainly in the Kankakee Basin, which was formerly occupied by an extensive lake or lacustral river — "Old Lake Kankakee'' of Bradley — and have been thought to be its shore accumulations; but their very wide extent and great mass relative to the lake area, as well as certain features of their known distri- bution, throw doubt upon the adequacy of this explanation. It would seem, froui a consideration of the glacial distribution of the second epoch, that this region must have been the avenue of discharge of vast quantities of water, shed from the adjacent slopes of the great glaciers occupying the basins of Lakes Michigan, Huron, and western Erie. The gi-eat accumulations of sand probably had their ulterior origin in this exceptional drainage, and were subsequently modified by lacustrine, Huvial, and a-olian action. Their history is one of much interest, and its satisfactory determina- tion can scarcely fail to reward industrious investigation when pursued in the light of the glacial phenomena now under consideration, and may, in turn, cast refiex light upon them. But however that may be, for the present, these dunes interpose an element of uncertainty in the tracing of the moraine at what would, in any event, be a critical portion of its course, for it is impossible to determine the character of the drift which they conceal. The extent of the sand in the Kankakee Basin and in distrii-ts to tlie south has been further iiivestigated by Chamberlin since the above was ' Geo]ogy of Illinois, Vol. IV, 1«70, pp. 226-229. -Third Annual Report, U. S. Geol. Snrvey, 1881-82, 1883, pp. 330-33L LAKE KANKAKEE. 329 written, as well as by Prof. A. H. Purdue and the writer. The limits have been determined with considerable accuracy, and the general features of the area have also been studied. The phenomena, as will be seen, are of a peculiarly puzzling natiu'e, and as yet a fully satisfactory interpretation of them has not been reached. EXTENT OF THE SAND. Beginning at the northeast and passing southward, the sand is found to have its eastern limit at the border of the Maxinkuckee moraine of the Saginaw ice lobe in western Marshall County, Indiana (see PI. VI). A few dunes occur on the moraine, but the continuous sand follows approximately the west border. Farther north, in St. Joseph County, a gravel plain occu- pies the outer or west border of the Maxinkuckee moraine. The moraine swings eastward along the north side of Tippecanoe River in northern Fulton County, and a narrow sandy belt extends up the Tippecanoe Valley along the outer border of this moraine as far as Rochester, but the east border of the main sand area continues southward through Avestern Fulton County and northwestern Cass County to the vicinity of Lake Cicott. Purdue reports that for aboiit 9 miles north of Lake Cicott a well- defined sand ridge forms the east border of the till plain that descends westward to the Tippecanoe River. This ridge turns abruptly westward near Lake Cicott and is nearly continuous to the Tippecanoe Valley at Monticello. For a part of this course the ridge lies along the north slope of a moraine of the Erie lobe. After crossing Tipjoecanoe River at Monticello the moraine turns south, while the ridg-e continues in a course slightly south of west about to the line of White and Benton counties. From this point a narrow sand ridge has been traced by Purdue in a course north of west nearly to Kentlaud, Indiana. There is, however, very little sand on the surface for several miles north from this ridge, and he did not succeed in tracing the ridge farther west. Purdue reports that there is a somewhat broken east-to-west sand ridge north of Indian Creek in southeastern Pulaski County, which passes through the village of Rosedale (Oak post-office), where it presents large dunes, and thence turning northeastward, terminates at a gravelly knoll in the north- east corner of T. 29, R. 1 W. The area from this ridge north to and beyond the middle of Tippecanoe Township is an extensive sandy plain, with the 330 THE ILLINOIS GLACIAL LOBE. exception of some short ridges of sand. There are also tlie following areas within tliis plain where sand is not present: (1) A small area in eastern Pulaski Connty, li miles north of Bruce's Lake; (2) an area south of Brace's Lake extending south to Little Mill Creek and west about 3 miles from the county line; (3) between Mill Creek and Little j\Iiir Creek; (4) a small area about Star City. This ridge has an altitude nearly as great as that of the ridge south of it, but its relation to that ridge and to the border of the sand area was not clearly worked out. Another nan-ow sand ridge was traced by Purdue from Monon Creek, about 5 miles southwest of the village of Monon, nearly directly west for about 20 miles to Percy Junction in Newton County. This ridge con- stitutes the south border of the naain sand area in Jasper County. West and ncirthwest from the western end of this ridge there are a few low sand ridges, but these occupy only a small part of the surface and do not have definite connection with each other nor with the long- ridge just mentioned. There is enough surface sand, however, to indicate that that region was covered by a body of water. The Iroquois moraine, on the north side of the Iroquois River, appears to have been partially submei-ged, but its highest parts probably rose above the water and shut in a bay on the south, in which wave action was not .sufficiently strong to foi'm heavy sand deposits. The south border of the main sand area follows the north slope of the moraine westward into Iroquois County, Illinois, and there swings south- ward with the Iroquois moraine to Coon Creek, in southwestern Sheldon Township, foi'ming apjjarently an outwash apron, as noted abo^■e. A belt of dunes leads westward from this sand area across Belmont and Crescent townships. There is considerable siu'face sand from this belt of dunes northward, but to the west and northwest only occasional low sandy ridges and tliin patches of sand are found. A sand ridge, as noted on a previous page, passes westward from the southwest part of the main sand area in central Iroquois County through Onarga and Ridgeville to the east fork of Vermilion River, through which there was probably a tem- porar^' westward outlet to the Vermilion Basin, and thence to the Illinois. Possibly this san PLEISTOCENE MAP OF SO UTHWT: STERN MICHIGAN Hi' FRANK LE\^RETT 1898. THE VALPARAISO MOEAINIC SYSTEM. 341 the west, but to extend the border between the lobes several miles to the west. This border assumes a nearly east to west coiu'se, across Otsego and Trowbridge townsliips. In the latter township it has the form of a double ridge with only the Kalamazoo River between the two members. A till plain tits closely about the border of the north member on the west and north, which rises toward the morainic ridge, apparently indicating that the Lake Michigan movement extended to this ridge. Similarly the south member is bordered by a plain on the south and east, which rises toward the ridge and indicates that it was formed by the Saginaw movement. The Saginaw movement apparently extended only to the western part of Trowbridge Township, for the ridge on the south side of the Kalamazoo River swings around on the west and south border of the till plain just referred to. The double I'idge, which in Otsego and Trowbridge townships trends toward the west, here becomes combined into a single belt and swings around through Cheshire Township to a southerly course. It pre- sents sloping till plains on each side rising toward it. As the combined morainic belt enters Van Buren County it again becomes separated. The Saginaw moraine turns to the east, crossing the northern part of Pine Grove Township, while the moraine of the Lake Michigan lobe bears nearly due south tlxrough the eastern part of Bloomingdale Township. An overwash gravel plain common to the two lobes, covering 5 or 6 square miles, separates the two moraines in western Pine Grove Township, while each moraine has a till plain fitting about its opposite border. In each ease the till plain rises toward the moraine which it borders. In the townships south of Bloomingdale and Pine Grove (Waverlj^ and Almena) both moraines are obscure near their line of junction, there being instead an extensive swamp, which borders Pawpaw River and is known as the Pawpaw Swamp, in which only occasional clusters of knolls appear. The Lake Michigan movement apparently extended about to the border between Waverly and Almena townships, for the till plain, which farther jaorth lies west of the eastern or outer member of the Lake Michi- gan movement, extends about to this line and borders the swamp just mentioned on the west. The Saginaw movement, which ^^roduced a bulky moraine in Pine Grove Township, has scarcely any morainic features in the township on the south. The till plain, which in Pine Grove Township lies east of the prominent morainic ridg-e, continues southward along the east border of the Pawpaw Swamp. 342 THE ILLINOIS GLACIAL LOBE. Immediately west of the -sdllage of Pawpaw, at the south border of the Pawpaw Swamp, the Lake Michigan moraine again becomes prominent. South of this latitude the Saginaw and Lake Michigan movements appar- ently lacked a few miles of meeting, and the interval is filled with a great gravel deposit through which the Dowagiac River has its course. The gravel j)lain descends toward the river from either border. It is therefore a double outwash, that on the west being the outwash from the Lake Michigan lobe and that on the east from the Saginaw Bay lobe. The gravel plain formed as an outwash from the Lake Michigan lobe is characterized by numerous lakelets, many of which are without surface outlet. The basins which they occupy are so deep that the water surface of the lakes is in some cases 40 or 50 feet below the general level of the gravel plain on their borders. Immediately west of Niles is a prominent morainic ridge which extends southwestward into Indiana and there turns south and dies away in the plain at the head of the Kankakee River. It is slightly outside the regular border of the Valparaiso moraine and is separated from it by a narrow valley- like depression occupied for a few miles, between Niles and Buchanan, by the southwest flowing portion of the St. Joseph River. This moraine belongs perhaps to the Saginaw series, for its trend harmonizes more closely with that of the Saginaw moraine east of it than with the Valparaiso moraine west of it. Furthermore, its surface bowlders apparently bear more resem- blance to those found in the Saginaw moraines than those on the Valparaiso moraine. The moraine is accordingly discussed in connection with the Saginaw moraines in another report now in preparation. A morainic tract in the northwest township of Cass County is also discussed in that report as a possible Saginaw moraine. From the State line of Michigan and Indiana the Valparaiso moraine bears southwestward and the neighboring Saginaw moraine (the Maxin- kuckee) bears southward while the broad Kankakee marsh with its border- ing gravel plains occupies the interval between them. Thus it appears that the two ice lobes in places had margins so widely separated that each ])rod;'iced a gravel apron of its own on its outer margin; in other places a single overwash apron was produced, as in Pine Grrove Township, Van Buren County, and Martin Township, Allegan Count}''; in other places the two glaciers formed moraines side by side, with no over- wash apron between, as in Trowbridge Township, where the Kalamazoo River flows between tliein; in Cheshire Township a single moraine was THE VALPARAISO MORAINIC SYSTEM. 343 produced by the two, and we find north of Pawpaw, the last extreme, a place where neither glacier produced a definite ridge at the point where the two lobes came in contact. RANGE IN ALTITUDE. The inner border of the Valparaiso morainic system, so far as examined, presents but little range in altitude, being usually between 650 and 690 feet above tide, or 70 to 110 feet above the level of Lake Michigan. From the inner border there is usually a rise of at least 100 feet, and in places of 200 feet or more, to the main crest of the morainic system. This crest in the Illinois portion ranges from about 750 feet up to nearly 900 feet above tide, being highest in the vicinity of Lake Zurich, in southern Lake County, and lowest on the borders of the Des Plaines River, in Will County. In the Indiana portion the crest ranges from about 750 feet in Lake County to nearly 900 feet in Laporte County. In the Michigan portion the crest is 750 to 800 feet in the vicinity of the St. Joseph River and northward nearly to the line of Allegan and Van Buren counties. But in Allegan Coiinty it presents more range, the highest points being fully 900 feet, while the low points near the Kalamazoo River rise but little above 700 feet. On the outer border of the morainic system the altitude is generally much higher than on the inner border, though in Kankakee and southern Will counties, Illinois, the difference in the elevation of the inner and outer borders is only a few feet. The difference is also slight in Lake and west- ern Porter counties, Indiana. In the ^dcinity of the Wisconsin line and southward as far as Elgin, Illinois, the outer border stands between 750 and 775 feet. It declines to about 700 feet at Naperville, Illinois, and to about 650 feet in southwestern Will County, Illinois It rises thence gradually eastward up the Kankakee Valley, reaching 700 feet in eastern Porter County, Indiana. There is then a more rapid rise and an altitude of about 800 feet is attained in the vicinity of Laporte, Indiana. This altitude is maintained eastward from Laporte to the border of St. Joseph County, Indiana. A descent there begins toward the St. Joseph River and the altitude decreases to about 710 feet on the borders of that stream north of Niles, Michigan. In j^assing northward, up the Dowagiac Valley, the altitude alono- the outer border of this morainic svstem increases to about 800 feet in Keeler and Hamilton townships, Van Buren County, Michigan. It declines again to about 700 feet at the Pawpaw marsh in 344 THE ILLINOIS GLACIAL LOBE. Alineiia Township, but rises to 800 feet at the gravel plain in western Pine Grove Township. At the Kalamazoo River it is only about 700 feet, but on the gi'avel plain in Mai'tin and Wayland townships, Allegan County, its altitude is 800 to 850 feet. The following table of elevations taken from the railway profiles which cross this morainic system, is designed to set forth the altitude of the inner border, the main crest, and the outer border. Numerals inclosed in parentheses represent the general elevation of the crest in the \'icinity of the railway line in places where the railway either makes a deep cut or passes the crest along a drainage line. Table of elevations on Valparaiso moraine. Elgin, Joliet and Eastern, in Lake County, 111 — \\ isconsiu Central Chicago, Milwaukee and St. Paul Chicago and Northwestern (Wisconsin Division) . Chicago and Northwestern (Omaha Division) Chicago, Burlington and Quincy Wabash Chicago, Rock Island and Pacific Illinois Central Chicago and Eastern Illinois Louisville, New Albany and Chicago (Chicago Division) Pan Handle Chicago and Erie Pittsburg, Fort Wayne and Chicago Chicago and Grand Trunk Baltimore and Ohio Lake Shore and Mithigau Southern Lake Erie and Western Chicago and Western Michigan Vaudalia Line Michigan Central Chicago and Western Michigan Kalamazoo and South Haven Division of Michi- gan Central Inner border. Feet. 720 683 646 650 641 646 665 630 650 632 640 650 650 660 650 670 675 685 690 680 080 670 680 Crest. Outer border. \ Feet. 880 823 812 867 760 (790) \\ 763 712 (750) 725 (750) 806 777 740± 740± 760± 775J; 825 (850) 831 863 863 (750) (750) 785 825 Feet. 770 778 768 772 750 700 a 680 a 680 a 710 a 713 660 673 685 730 770 775 800 790 775' 730 730 710 800 a Outer border of main ridge. THE VALPARAISO MOEAINIO SYSTEM. 345 SURFACE CONTOURS. The Valparaiso morainic system is nearly as complex as the Blooming- ton and Champaign systems, but it does not admit of separation into such distinct ridges. Around the southwestern end of the loop in Dupage and Will counties, Illinois, it is possible to trace three distinct crest lines. Usu- ally, however, there are but two, and in places but a single crest. Where most cleal-ly separable into distinct ridges, there is one ridge which much exceeds the others in bulk, and constitutes the main ridge of the system. Where not clearly separable, the minor ridges either become coalesced with the main ridge or present imperfect ridging. In the vicinity of the Wisconsin and Illinois line and thence southward through Lake County, Illinois, the main ridge occupies the eastern ^^art of the system. In the western part the ridging is less definite, though the morainic expression is in places more pronounced than in the eastern part. Upon passing southward across northwestern Cook County a minor ridge makes its appearance on the eastern slope, and is separated from the main ridge by the valley of Salt Creek. This ridge continues across Dupage County. The main ridge covers nearly the entire width of the system in northwestern Cook County, but in Dupage County there is not only the minor ridge on the eastern or inner border, but also one on the western or outer border of the system. The valley of East Dupage River separates the main ridge from the minor ridge west of it. From the vicinity of the Des Plaines River eastward to the border of Indiana the three ridges just mentioned are distinctly traceable, the main ridge occupying the central part of the system and the minor ridges the outer and inner borders. The ridge on the outer border is in places sepa- rated from the main ridge by a narrow plain, but is closely associated with it near the State line and also from the Des Plaines River northward. The interval between the main ridge and the minor ridge on the inner border is narrow and generally nearly as undulating as the ridges. Near Matteson, however, a small plane tract separates the two ridges. In Lake County, Indiana, the ridge on the north or inner border of the morainic system becomes nearly as prominent as the main ridge, and constitutes the water parting between the Kankakee River system and Lake Michigan. It also constitutes the water parting in a few places west of the State line. 346 THE ILLINOIS GLACIAL LOBE. Upon passing eastward from Lake County, Indiana, tlie several ridges become combined into a single gi'eat ridge which admits of but little sep- aration into distinct members in Porter and Laporte counties, Indiana, and in southern Berrien County, Michigan. In northeastern Ben'ien County two distinct ridges are developed, between which Pipestone Creek flows in a southwestward course. Farther north the morainic system consists usually of a main ridge on the eastern or outer border and ridges of more or less definiteness near the western border, between which there are lower tracts with gently undulating surface. The ridges just discussed, although bulky, are in places less impressive topographic features than the knolls and basins which dot their surfaces. They usually rise gradually from border to crest, and their dimensions can be appreciated only by measurements with surveyor's level or other instru- ments. The inner border in Porter and Laporte counties, however, usu- ally shows an abrupt rise of 100 feet or more and portions of the inner border in Michigan are also abrupt. Such is the case in the vicinity of the St. Joseph River in central Berrien County, and at frequent intervals from that river northward to the Kalamazoo River. Considerable variation in surface contour is displayed in each of the States which this morainic system traverses. In the Illinois portion the surface is usually gently undulating, with knolls 15 to 30 feet in height, separated by winding sags and shallow basins. The trend of these knolls, when on the crest and outer part of tlie morainic system, is usually about in line with the trend of the ridges whose surface they occupy. Near the inner border of 'the moraine, however, the knolls frequently show a tend- ency to elongation at right ang-les with the trend of the morainic system. The crest of the main ridge often rises abruptly 30 or 40 feet above the remainder of the moraine in a narrow ridge or chain of knolls. In Lake Covmty, Illinois, there are numerous small lakes occupying the basins among the morainic Icnolls. These range in size from a few acres up to several square miles. They are usually shallow, a depth of 50 feet being seldom attained, wliile tlie majority are but 10 or 15 feet. Among the lakes there are knolls and irregular ridges rising 10 to 50 feet abo^"e the surtace. Some of the lakes are bordered by extensive marshes on one or more sides, which were formerly probably covered by the lakes, for it is not rare to find beaches a few feet above the present level of a lake. This morainic THE VALPARAISO MORAmiO SYSTEM. 347 system, as indicated below, is deeply trenched by the outlet from the gla- cial Lake Chicago, which discharged from the southern end of the Lake Michigan Basin through the Des Plaines Valley. In Lake County, Indiana, the contours are generally subdued, there being few knolls more than 20 or 30 feet in height. Tributaries of the Kankakee lead soutliAvard from the belt on the north border, greatly inter- rupting the continuity of the main ridge. Similarly in Will County, Illinois, the main ridge is trenched by the headwater tributaries of Hick- ory Creek and of other streams flowing southward to the Des Plaines or Kankakee. In Porter and Laporte counties, Indiana, the moraine is characterized by sharper knolls than in Lake County and, as noted above, rises with great prominence on its inner border. Lakelets are inclosed among the knolls and occur also on the outer border of the morainic system in basins occupying the edge of the overwash gravel apron. From the line of Indiana and Michigan northward the morainic system usually presents sharp contours. The knolls range in height from 15 or 20 feet up to 60 or 80 feet. There are several places in which elevated tracts several square miles in extent rise above the general level of neighboring portions of the moraine. The most notable instances are as follows: In Bainbiidge Township, Berrien County; in central Lawi-ence Township, Van Buren County; in southern Arlington Township, Van Buren County; in northern Bloomingdale Township, Van Buren County; in northwestern Trowbridge and northern Cheshire townships, Allegan County, and in a tract north of Allegan. There is usually ah abrupt border on two or more sides of these tracts, with a relief of 60 to 100 feet above neighboring por- tions of the moraine. In the elevated tract north of Allegan the descent is abrupt both on the north and east sides, and in Cheshire Township on the north and west sides. The morainic tracts in northern Bloomingdale and southern Cheshire have no very abrupt borders. The tract in Arlington Township, with arm-like projections into Hartford Township, has an abrupt border on all sides. The tract in Bainbridge Township has an abrupt border on the north and west and also on portions of the east and south. Were it not for the relief, these tracts would differ but little from the neighboring lower portions of the morainic system, for they usually present only small knolls and ridges on their surfaces. 348 THE ILLINOIS GLACIAL LOBE. A few small tracts of elevated land occur along- the west border of the morainic system in southwestern Michigan. Such tracts in Geneva, Bangor, and Watervliet townships, Van Buren County, have extreme elevations of 50 to 75 feet above the bordering plains. The swells rise one above another in passing from the plains to the highest portions of these tracts and the border is less abrupt than in the larger tracts above mentioned. There are a few points where very sharp knobs were noted which rise 60 or 80 feet above the border portions of the moraine. These occur in Wat- son Township, Allegan County; in the vicinity of Great Bear Lake in Van Bui-en County; on the south side of Pawpaw River, near Lawrence, and in several places along the eastern border of the morainic system in Van Buren and Berrien counties. In the Michigan portion of this morainic system marshes are a verv common feature, there being usually several inclosed among the morainic knolls in each township. Lakes are also a common feature from northern Berrien County northward. They are in some cases two or three square miles in area, but usually occupy less than a square mile. So far as known they are shallow and, like those of the Illinois portion, are bordered bv marshes which seem to have been formerly covered by lake water. There are also lakes along- the eastern border of the morainic system indenting the gravel plain. These are conspicuous in northwestern Cass and southern Van Buren counties. DETAILED DESCRIPTION OF THE MICHIGAN PORTION. The Michigan portion of ihis morainic system was examined in more detail than the remainder of the system because its surface contours are more variable and because it had received very little attention from the earlier students. It seems appropriate, therefore, to present the following detailed discussion of the topograph}- of this portion. The area first con- sidered lies in central Allegan County, and the discussion is then extended to points farther south. In T. 2 N. the moraine consists of two well-defined ridges separated by a till plain. A line passing across the morainic system from west to east shows the following features: West of the western ridge is a broad plain covered with sand called the " Pine Plain." This plain stands 50 to 75 feet above Lake Michigan. In passing eastward from it an abrupt rise is made THE YALPAEAISO MOEAINIO SYSTEM. ^ 3^9 into a belt of billowy land standing 200 to 260 feet above the lake, the most elevated portion being at the east in central Allegan Township. Here a sudden descent is made to a narrow till plain standing 150 to 160 feet above Lake Michigan, east of which an abrupt rise takes place in Watson Township to an elevation of 260 to 330 feet above the lake, or 840 to 910 feet above tide. This rolling belt continues to the west part of Martin Township, where a gravel apron borders the ixioraine, having an elevation of 240 to 260 feet above Lake Michigan, or 820 to 840 feet above tide. The very elevated portion of the moi'aine in Watson Township appears to be doubled upon itself in a peculiar manner. Its western part is bordered on the north, west, and south by a till plain, and this western end forms a very prominent part of the moraine, having knobs 80 feet or more in height above the bordering basins and plains. Passing now to T. 1 N., it is found that the eastern portion of the moraine in Watson Township continues to the south part of that township and there turns abruptly to the west, following the north side of the Kala- mazoo River from Otsego to Allegan, along the south border of the till plain referred to above. At AUeg'an it joins a rolling sandy tract which lies west of that city, and the combined belt takes a southwesterly course, occupying nearly the whole of Cheshire Township. The north and west tiers of sections are partly on the moraine and partly on the sandy plain which borders it on the west. The morainic system is here narrowed to the width of a single township and has the Saginaw moraines combined with its eastern border and the Pine Plains bordering it on the west. Passing to T. 1 S., the morainic belt is found to spread out to a width of nearly 15 miles. Its inner border takes a nearly west course to the vicinity of Grand Junction. It then passes south to Breedsville, lying a short distance east of the Chicago and West Michigan Railroad. West from this railroad in Greneva Township are isolated tracts with undulatory sur- faces surrounded by marshes, swamps, and till plains. These knolly tracts extend in two instances north across the base line into Allegan County, so that the whole district south of the "Pine Plains" in both T. 1 N. and T. 1 S. and east of a till ridge (Covert Ridge) which borders Lake Michigan in South Haven and Casco townships, is in places more or less morainic in topography, but the main morainic belt lies east of the Chicago and Western Michigan Raihoad. 350 THE ILLINOIS GLACIAL LOBE. Passing eastward over this belt there is an ascent, gradual at first, over a sandy tract in Columbia Township, then over an undiilatory till ridge in Bloomingdale Township, which changes to a plain in the central part of the township ; then in the eastern part of this township a rapid ascent is made to the high portion of the moraine which forms the eastern border of the Lake Michigan di-ift. This border is at Gobies, on the line of the Kalama- zoo and South Haven Division of the Michigan Central Railroad, and lies near the line between Bloomingdale and Pine Grove townships throughout their whole length. The following elevations of stations along the railroad give a fair idea of the rise of the moraine toward the east from Grand Junction to Gobies: Elevations of stations along the Kalamazoo and South Haven Division of the Michigan Central Railroad. Feet above tide. Grand Junction 678 Columbia 682 Berlamont 700 Bloomingdale 731 Gobies 803 At least 60 feet of the rise between Bloomingdale and Gobies is made within 1^ miles of the latter town. There is scarcely any descent to the border of the overwash plain or apron east of Gobies, but this plain descends 20 feet or more in a mile toward the east to the border of the Saginaw moraine near Pine Grove Mills. This may not be true except along the railroad, but since this passes through a wide part of the over- wash plain the fact is significant. In T. 2 S. the morainic ridge which is so prominent at Gobies grows feebler for 3 miles or more along the line between Almena and Waverly townships, as it approaches Pawpaw. River, rising scarcely 50 feet above this stream and still less above Brandywine Creek, which lies along its western border. The undulations are less sharp than in T. 1 S. On tlie south side of Pawpaw River the outer border of the moraine takes a nearly east to west course for 5 or 6 miles. Its prominent portion lies mainly in T. 3 S., barely reaching into Waverly Township. There is a gap 2 or 3 miles long just nortli of the village of Pawpaw whei'e no moraine is devel- oped, but the swamps which follow Pawpaw River are bordered on the east by the overwash ajiron of a moraine of the Saginaw series. West of Pawpaw the moraine assumes a strength of development even greater than THE VALPAKAISO MOEAINIC SYSTEM. 351 that near Gobies, rising nearly 150 feet above the Pawpaw River swamps, 4 to 6 miles west of the village of Pawpaw, and haA'ing a breadth from the swamp on the north to an overwash apron on the south of only IJ to 2 miles. Waverly Township is much of it comparatively level and swampy, but the topography of the northwestern part is morainic. This belt connects on the north with the morainic belt which passes through western Bloom- ing'dale and eastern Columbia townships. In northeastern Arlington Township, which adjoins Waverly on the west, is a swamp, which comprises about one-third of the township. It is bordered on the north and east by the billowy belt in Columbia, Blooming- ton, and Waverly townships, and on the southeast by an elevated billowy tract in Arlington Township, which constitutes the most prominent portion of the moraine in this tier of townships. This prominent morainic belt extends southwest through southeastern Bangor Township to the Pawpaw River, near Hartford. Its south border lies along the river for a distance of nearly 10 miles from the east line of Arlington Township to the village of Hartford. The river is also bordered on the south by a similar promi- nent belt, which is described in connection with the next tier of townships. Bangor Township, which lies west of Arlington, has a series of swamps, till plains, and island-like billowy tracts, the swamps and till plains together occupying more than half of the surface. The moraine in this tier of townships, therefore, has a width of about 18 miles, and is highest in the middle portion, while in the tier of townships on the north it is nearly as wide, but its most prominent part is the eastern border. The curve in the outer border of the moraine makes the prominent morainic belt south of Waverly Township the correlative of the morainic belt near Grobles, in T. 1 S., and this belt is more prominent than the middle portion in Arhngton Township. The rule, therefore, still holds good — if we overlook the break north of Pawpaw — that the eastern or outer border is the highest part of the moraine, and this rule continues to apply as far south as the Indiana line. In T. 3 S., at the western border of the morainic belt in Watervliet Township, there is immediately east of the till ridge which cuts across its northwest corner a series of till plains interspersed with island-like billowy tracts and dotted with lakelets, differing from Bangor Township in having 352 THE ILLINOIS GLACIAL LOBE. lakelets instead of swamps. In Hartford Township, which borders Water- vliet on the east, there are till plains, sand plains, and island-like billowy belts over about two-thirds of the township, but the two tiers of sections in the east contain an elevated part of the moraine. Lawrence Township, which lies east of Hartford, has a prominent part of the moraine occupying' nearly the whole of its surface, there being but two notable exceptions, the valley of the Pawpaw River, which passes from east to west through the northern part of the township, and the overwash apron which borders the moraine in the east part of the township. The overwash apron swings around the moraine across Hamilton Township, which lies south of Law- rence, and thus in the north part of T. 4 S., as well as in T. 3 S., the morainic border has for several miles a neai'ly east to west trend. Contin- uing its course in T. 4 S., we find the morainic border turning southwest near Keeler Center and entering Cass County from the southwest comer of Keeler Township, cutting off a section or more of this county in its extreme northwest corner, then entering the eastern part of Pipestone Township, Berrien County. Passing westward through T. 4 S., the moraine becomes prominent in western Keeler, Bainbridge, and eastern Benton townships. It divides in the southern part of Bainbridge township at Pipestone Lake, and from this point south, in Pipestone Township), incloses a low belt along the Pipestone River in which flowing wells have been obtained. The eastern limb passes southwest through the southeastern part of Pipestone Township, and the western limb passes southwest across the northwest corner of Pipestone Township into Sodus Township and occupies the eastern portion of this township to the St. Joseph River. From Benton Township southward nearly to the Indiana line the west- ern or imier border is more sharply defined than it is north of this township. It rises abruptly 100 feet or more above the swamps or till plains which lie along the foot of the range of sandy hills which form its front. For a few miles in southern Berrien County, Michigan, this border is not abrupt, but upon passing into Laporte County, Indiana, it again becomes abrupt and continues so across Laporte and Porter counties. Along the eastern or outer border in Berrien County lakes are numerous. They are usually in deep depressions 50 feet or more below bordering portions of the moraine. There are also lakes on the gravel plain outside the moraine, occupying basins THE VALPARAISO MOEAI^flC SYSTEM. 353 sunk 30 to 40 feet or more below the general level of tlie plain. The St. Joseph River is bordered by broad gravelly teiTaces 2 miles or more in width from the inner border of the moraine southward a short distance beyond Berrien Springs. From this point up to Buchanan the moraine bor- ders the valley closely on each side. Above Buchanan the river is again bordered by gravel terraces which are cut in the gravel- plain that was formed on the outer border of the moraine. THICKNESS OF THE DRIFT. Situated as the Valparaiso system is, in a district over which there have probably been several successive ice advances with intervening recessions, the drift can scarcely be supposed to belong solely to the advance which formed this morainic system. It is known that remnants of the sheets of the lUinoian and lowan drift are present in northeastern Illinois and northwestern Indiana. There is also present a considerable amount of drift of the early Wisconsin series. The early Wisconsin drift is so similar to that of the Valparaiso drift sheet that it is doubtful if it can be readily distinguished or separated from it. There does not appear to be a well-deiined soil horizon at the base of the Valparaiso sheet to mark the line of junction, such as occurs under wide ai-eas at the base of the early Wiscon- sin drift. The thickness of the Valparaiso di'ift sheet can perhaj)s be best estimated by the relief, for it can scarcely be assumed to exceed greatly the measure of the outer-border relief of the moraine, except in jDlaces where there is a great gravel filling on that border. The gravel filling is of little consequence on the outer border of the Valparaiso morainic system in Illinois and in Lake and Porter counties, Indiana. Farther east and north it is of considerable depth. The relief in the Illinois portion is estimated to average about 65 feet. The average thickness of the Valparaiso sheet is probably somewhat less than the relief, since the sheet is markedly thinner on the borders of the morainic system than along its main crest. In southwestern Michigan it is difficult to determine whether the early Wisconsin sheets are present in large amount. A fresh diift of great depth is found along the line of the morainic system and westward from it to the borders of Lake Michigan. In all probability the thickness of the Val- paraiso sheet is as great in southwestern Michigan as in northeastern Illinois and northwestern Indiana, and it may be even greater. MON xxxviii 23 354 THE ILLINOIS GLACIAL LOBE. The combined thickness of the several sheets of drift has been deter- mined at various points along the line of this morainic system, while at other points wells have been sunk to great depth without reaching the bottom of the drift. The rock surface beneath the di'ift appears to be quite uneven, there being a known range from about 100 feet above the level of Lake Michigan to more than 100 feet below the surface of the lake. The following list of deep borings sets forth the A^ariations in the thickness of the drift and the elevation of the rock "surface : List ofboriugs showing thickness of drift along the Valjiaraiso morainic system. At I vanhoe, Illinois, on crest Near Lake Zurich, on crest At Lake Zurich, 20 to 30 feet below crest Haines vi lie, near crest G ilmer, near crest Crest east of Wauconda Crest south of Barringtou Barriugton, 40 to 45 feet below crest East of Elgin, near crest Palatine and vicinity Near Schanmberg, along crest Arlington Heights, about 150 feet below crest North of Arlington Heights, 20 to 30 feet above station . Near Spauldiug, about 50 feet below crest Bartlett, 10 to 20 feet below iTest Ontarioville, near crest Roselle, about 50 feet below crest Crest south of Bloomiugdale Itasca Bcuseu ville Elmhurst Turner .Junction Crest east of Naperville Downer's Grove Crest cast lue clay with few pebbles 10 Total 27 On the south border of BeiTien County, Michigan, in sec. 19, T. 8 S., R. 20 W., two wells 85 feet in depth are mainly through a soft blue till containing but few pebbles. In that vicinity the blue till is often found ■n'ithin 4 feet of the surface. On the ridge at Three Oaks wells usually penetrate 6 or 8 feet of yellow till before entering the blue. Soft blue till extends to a depth of 70 feet, and there water-bearing sand is usually struck. At New Buffalo, Michigan, the blue till is frequently exposed at depths of but 4 or 5 feet, and the wells in the higher part of the village usually penetrate about 60 feet of blue till before striking a water-bearing bed. On low gi'ound near the shore of the lake flowing wells have been obtained at a depth of about 30 feet. The drift at New Buffalo, as reportetl in an early ' Geol. of Indiana, 1873, pp. 47(M7I. THE LAKE BORDER MORAINIC SYSTEM. 399 volume of the Indiana Survey, has a depth of 212 feet at the Michigan Central Station, whose altitude is only 20 feet above the lake.^ At Sawyer a deep well made by Mr. Rough has the following section: Section at Sawyer, Michigan. Teet. Surface sand 3 Blue till, wltli sand bed at 25 feet and at bottom 120 Rock of bluish color, varyingin hardness 208 Total deptb 331 An exposure in the south bluff of Galien River, at New Troy, where the till ridge is undermined by the stream, shows a slightly pebbly blue clay from the river's edge up to a height of about 40 feet. Above this clay there is a brown till interbedded with calcareous sand, having a thickness of 12 feet. A well in the village of New Troy raaj^ have struck rock at a depth of 65 feet, though the owner of the well thinks that sand and gravel was entered below the supposed rock ledge. In case the latter interpreta- tion is correct the former is probably erroneous. At the point where the Gralien River cuts through Covert Ridge, in sec. 2, T. 8 S., R. 20 W., there is sand at the top of the bluff 12 feet in depth, below which is a brown pebbly clay interbedded with sand which is' quite calcareous. Both the till and the sand are in beds which are in arch- ing and oblique attitudes. On the north bluff of the river nearly opposite this point a well 96 feet in depth entered blue till at 2 feet and continued in it to the bottom. At Bridgman a boring 250 feet in depth entered rock at 140 feet, and struck an inflammable gas at about 160 feet which would burn a jet several feet in height. The rock is apparently a shale. The upper 80 feet of the drift is mainly blue till, but the lower 60 feet is gray sand, yielding water. Along the St. Joseph River there are extensive exposures of blue-gray till in the west bluff from St. Joseph southward to the mouth of Hickory Creek, but in the east bluff exj^osures were found in which there is a blue silt free from pebbles rising to a height of 30 feet or more above the stream. This silt is usually capped with 15 or 20 feet of sandy ^-avel. A well near the east bluff, 2J miles south of Benton Harbor, reached a depth of 153 feet without entering rock, and is mainly in blue clay; whether silt or till ' Op. cit., p. 431. 400 THE ILLINOIS GLACIAL LOBE. was not ascertained. East from here, in the vicinity of the mouth of Pipe- stone Creek, typical till is found in the east bluff of the river. A well on this bluff, in sec. 1, T. 6 S., R. 18 W., 138 feet in depth, does not reach rock. It penetrated about 30 feet of gravel, beneath which it was mainly in a blue till. At St. Josejih a well at the Park Hotel, 165 feet in depth, enters rock only 4 feet and obtains a water that is slightly lirackish. The upper ■40 feet is mainly in blue till, biTt the remainder of the drift is largely a fine sand in which there are occasional beds of clay or silt cai'rying fragments of wood. Wood is especially abundant at about 140 feet. Rock was struck at the basket factory in St. Joseph at about the same level as in the hotel well, and a slightly brackish water was obtained. An experimental gas boring at Benton Harbor, on low ground scarcely 15 feet above lake level, penetrated 135 feet of drift and sand. The upper 20 feet was entirely sand. Beneath this is a blue clay or silt, containing few pebbles, which graduates downward into a gray sand, also slightly pebbly, and this sand extends to the rock. A well on the east border of Covert Ridge, in sec. 9, Watervliet Town- ship, reached a depth of 125 feet without entering rock. It was tlu-ough till with the exception of 5 feet of sand at the bottom. Another well in the same section entered blue till at 4 feet, which continued to the bottom of the well at 52 feet. Here a cemented gravelly crust was penetrated, beneath which water was obtained. A boring on Covert Ridge, in sec. 34, Covert Township, at W. F. Conners, reached a depth of 220 feet without entering rock. It was mainly through blue till and no water was obtained; a dug well only 6 feet from it found water-bearing gravel at 36 to 38 feet. Two wells just west of the village of Covert, in sec. 15, are 70 feet in depth. They penetrate 15 feet of yellow till, beneath which is a blue till extending to the water-bearing sand at the bottom of the wells. A well in the northeast corner of sec. 22, 80 feet in depth, is in till from top to bottom. A well on the west side of sec. 22, 97 feet in depth, penetrated 3 feet of surface sand, beneath which it was entirely in till to a water-bearing sand at bottom. A well in the north part otf sec. 14, 100 feet in deptli, passed through thin beds of sand which occur in the till at intervals of 15 or 20 feet. A well near the center of sec. 11 has a depth of 85 feet and is in till THE LAKE-BORDER MORAINIC SYSTEM. 401 from the top down to a quicksand at tbe bottom. A well in the SE. ^ of sec. 2 has a depth of 70 feet and is in till with the exception of 4 feet of surface sand. A well in the west part of sec. 25, South Haven Township, is in till from the top to a water-bearing sand at bottom. A well one-half mile southeast from South. Haven, 125 feet in depth, is in till except 5 feet of water-bearing sand at bottom Several tubular wells in the village of South Haven have a depth of about 100 feet. After penetrating a few feet of surface sand they are in blue till nearly the whole depth. Some of the shallow wells in the villag-e obtain water at the base of the siniace sand. A boring at the basket factory in South Haven has the following section: Section of boring at basket factory in South Raven, Michigan. Feet. Surface sand 10 Soft blue clay, slightly pebWy, liecommg liarder toward bottom and containing bowlders in the lower 20 feet 130 Shale of dark color, varying in hardness 207 Total 347 On the plain east of Covert Ridge, in sec. 31, Geneva Township, a flow- ing well was obtained on the farm of J. Irving Pearce. Water rises 7 feet above the surface. The drift is mainly a blue till and has a depth of 190 feet. The well was continued 40 feelj into the underlying shale. A well on the plain east of Covert Ridge, in sec. 29, Casco Township, Allegan County, reached a depth of 140 feet without entering rock. After penetrating 25 feet of surface sand it passed through a thin bed of blue pebbly clay, beneath which it was entirely through fine sand. On Covert Ridge, in sec. 25, T. 1 N., R. 17 W., a well 157 feet in depth penetrated 18 feet of surface sand, beneath which it was mainly through a blue-gray till. Another well in the same section penetrated 12 feet of sur- face sand, beneath which it was in a blue till to a depth of 146 feet. A well in the northeast corner of the same section penetrates scarcely any surface sand; there is instead a loamy yellow till 7 feet in depth, overlying the blue till. The latter is slightly pebbly and extends to a depth of 104 feet. There is then about 10 feet of stony material of reddish-brown color. This is underlain by blue clay, which extends to the water-bearing sand at 130 to 134 feet. MON XXXVIII 26 402 THE ILLlISrOIS GLACIAL LOBE. A well in sec. fi, on the inner slope of Covert Ridge, has tlie following section : Section of ivell on Covert Ridge in sec. 6, T. 1 N., R. 17 ir. Feet. Surface sand 12 Blue clay, slightly pebbly 10 Fine white sand with a few pebbles 32 Cemented gravel alternating with beds of loose gravel 24 Total 78 In sec. 12, T. 1, R. 17, also on the inner slope of Covert Ridge, wells 30 to 50 feet in depth are mainly through sand, and the lake border from this point northward is heavily coated with sand. On the outer slope of Covert Ridge, in northern Casco TownSliip, till appears to have been deposited upon a thick bed of sand. The wells enter this sand at a depth of 10 to 25 feet, and those sunk to a depth of 35 or 40 feet do not reach the bottom. On a swamp south of Covert Ridge, in southeastern Ganges Township, wells usually pass through a compact clay after leaving- the surface muck, and find some difficulty in obtaining water in dry seasons. A well in sec. 36 reached a depth of 98 feet and found only a weak vein at about 40 feet. A well on the crest of Covert Ridge, in sec. 16, Ganges Township, at an altitude about 100 feet above the lake, reached a depth of 275 feet with- out entering rock. Its section is as follows: Section of toell on Covert Ridf/e, in Ganges Township, Allegan Cotmty, Michigan. Feet. Surface sand 6 Blue till fi^ Blue quicksand 1* Yellow sandy clay with pebbly layers loO Blue till ■-■ -'' • Yellow sandy clay, chauging to saud at bottom , 30 A well in the northwest part of sec. 15, also on the crest of Covert Ridoe, penetrated 30 feet of surface sand, beneath which was a blue till extending to the water-bearing sand at 86 feet. A well on the crest of the ridge, near the line of sees. 3 and 4, at an altitude 105 feet above the lake, reached a depth of 190 feet without eiiter- iuo- rock. There is 8 feet of yellow till at the surface, beneath which the well apnears to have been entireh' in a blue-gray till. In the vicinit)' of Hutchinson's Lake the wells range in depth from 40 to 105 feet and are largely through sand or sandy gravel. THE LAKE-BOEDEE MOEAINIC SYSTEM. 403 At Fennville wells in some cases penetrate 50 feet of sand, with which there are thin beds of peaty material associated. A hill east of this village, which stands about 50 feet above the level of the railway station, has till at the surface. At Drenthe, on the inner slope of Covert Ridge, in southern Ottawa County, flowing wells have been obtained; one in a ravine at the sawmill has a head 8 feet above the surface and will flow 80 barrels per day from a 2-inch pipe. The water is obtained from sand below blue till at a depth of 92 feet. Another well a few rods Avest is siphoned into a trough in the same ravine. A well 1 mile north of Drenthe, 155 feet in depth, is mainly through blue till, except in the lower 15 feet, where water-bearing- sand and gravel is found. Its head is sufficient to barely reach the surface. Manv wells along- the ridge east and south from Drenthe have been sunk to a depth of 100 feet or more, mainly through blue till. The till sheet extends westward from this ridge to the shore of Lake Michigan in north- western Allegan County. CHARACTER OF. THE OUTWASH. The Valparaiso morainic system formed a retaining wall for waters escaping from the ice sheet along- the outer border of the ridges xmder dis- cussion, except at the "Chicago Outlet," and possibly at the St. Joseph River Valley. It is probable therefore that the district between the ice margin and the Valparaiso morainic system was occupied either by lakes or by very sluggish streams, except perhaps for a few miles in Lake and northern Cook counties, Illinois. There are found indications of a moderate rate of flow, accompanied by gravelly outwash, along the Des Plaines Valley below the jioint where the outer ridge crosses the river near Griirnee. The force of the current was sufficient to carry the gravel as far down the valley as the vicinity of Des Plaines Village and form a belt a mile or more in average width. The gravel is only a few feet in depth. Much of the low country bordering these ridges in southern Cook County, Illinois, and in northwestern Indiana and southwestern Michigan has been covered by the waters of Lake Chicago, and the deposits made by this lake can not easily be separated from any deposits of similar character which nvAv have been formed as an outwash from the ice sheet. There are 404 THE ILLINOIS GLACIAL LOBE. places wnere wells encounter a more pebbly material at the base of the sand than near the surface, but it is not certain that these pebbles were an outwash from the ice sheet. Indeed, it seems quite probable that they may have been worked over and deposited by the waters of the lake. ASSOCIATED TILL PLAINS. The ridges just discussed occupy but a small portion of the area embraced between the Valparaiso morainic system and the shore of Lake Michigan. The greater part of the area is a plain, underlain by till deposits. The plane tracts, as is shown later, were largely covered by Lake Chicago and' have received deposits of sand or gravel from the waters of that lake. ALTITUDE AND SLOPES. In the portion of the plain west and south from Chicago the altitude at the inner border of the Valparaiso morainic system is 40 to 50 feet above Lake Michigan. From this border there is a e-radual descent toward the lake, and. the till scarcely rises above lake level along the present shore within the limits of the city. At the time the upper or Grlenwood beach was formed lake water covered the entire plain west and south of the city as far as the borders of the Valparaiso morainic system, the altitude of that beach being 55 to 60 feet above the present lake level. Upon passing northward this till plain is divided into several narrow plains which separate the till ridges, and these plains soon rise above the level of the upper beach. The plain that lies between the west ridge and the Valparaiso moraine slopes eastward at the rate of several feet per mile. Its rise toward the north amounts to but IJ to 3 feet per mile. At Oving- ton Station, on the Omaha Division of the Chicago and Northwestern Rail- way, the west border next the Valparaiso moraine is but 635 feet. It rises to about 690 feet at the line of Cook and Lake counties, a distance of 18 miles, and to about 725 feet in northern Lake County, a distance of 24 miles farther. The i)lain between West and Middle ridges rises from 030 feet at Oak Glen to 680 feet at Deerfield, a distance of 6 miles. From Deerfield north to the State line, a distance of 24 miles, it is shown by the Chicago, Milwaukee and St. Paul Railway profile to stand at (5 70 to (i85 THE LAKE BOEDER MOEAINIC SYSTEM. 405 feet. Russell Station, situated on this plain near the State line, is 673 feet. The plain between Middle and East ridges rises from 630 feet, opposite Winnetka, to about 670 feet at the point where the ridges unite, 20 miles north from Winnetka. In Indiana the border next the Valparaiso morainic system stands 50 to 70 feet above Lake Michigan, the lesser altitude being near the Illinois line and the greater near the Michigan line. The plain between the Val- paraiso moraine and the outer till ridge is but 2 to 3 miles Avide in Porter and Laporte counties; it however shows a descent toward Lake Michigan. There is also a percej^tible descent from the till ridge toward the lake. In western Porter and in Lake counties the slope is apparently continuous toward the lake from the border of the Valparaiso morainic system, no well- defined till ridge being present. For a distance of 2 to 5 miles south from the lake the sand deposits capping the till are heavy and their base is about as low as the surface of Lake Michigan. In Berrien County, Michigan, the plain between the Valparaiso morainic system and the outer till ridge stands 60 to 90 feet above Lake Micliigau and has a slight descent toward the lake. As it is but 2 to 4 miles in width, the west border is only a few feet lower than the east. The plain between the outer ridge and Covert Ridge stands 50 to 75 feet above Lake Michigan, and also has a slight descent toward the lake. Its width in places is less than a mile and nowhere exceeds 3 miles. In Van Buren and Allegan counties the lowland tract between the Val- paraiso morainic system and Covert Ridge is less smooth than the southward continuation in Berrien County. There are occasional ridges and knolls of glacial drift ranging in height from 50 feet downward to 10 feet or less. There are also numerous sandy ridges and knolls with a heiglit ranging from 30 feet downward to barely detectible waves in the surface. The presence of the sand has tended to make the surface more uniform in eleva- tion, since it is deeper in depressions than on the higher points. The plane- surfaced part of the lowland stands usually 75 to 100 feet above Lake Michi- gan, while the knolls occasionally reach a height of 150 feet or more above the lake. This lowland tract presents greater oscillations in level in passing from north to south than from west to east. It is generally somewhat lower on the borders of the valleys than on the divides between them. If the 406 THE ILLINOIS GLACIAL LOBE. sand were removed the variations would be still greater, since the sand is thicker on the borders of the valleys than on the divides. Covert Ridge follows the shore of Lake Michigan so closely that a plain is present on its inner border along only a small part of its course from the State line northward to the Kalamazoo River. Where present it shows a descent of 20 or 30 feet per mile toward the lake. In places where the ridge is distant 2 or 3 miles and its inner border stands 60 to 70 feet above the lake the till surface drops down nearly to lake level at the lake shore. Sand deposits have considerable depth on the lower parts of this plain and bring the surface up to a height of 35 to 40 feet or more above the lake. THICKNESS OF DRIFT. On the Illinois portion of these plains there is much difference in the thickness of the drift. The difference in thickness is due almost entirely to the variation in the surface of the underlying rock strata, since the surface of the plains has only a slight variation in altitude. Within the city of Chicago, where the surface is especially flat, several rocky prominences come to the surface, or are concealed but slightly by drift, while among them the di-ift accumulations extend to depths of 100 to 125 feet or more. Mr. Samuel Gr. Artingstall, formerly city engineer, has prepared a map of the city showing the distance to rock in many places. This indicates that a filled valley with rock floor 100 to 125 feet below lake level passed through the north central part of the city, entering the lake south of Lin- coln Park. West from the city the rock rises over quite extensive areas nearl)' to the surface of the jjlain or to a height of 30 to 60 feet above the level of Lake Michigan. In northern Cook and in Lake County, betAveen the till ridges as well as beneath them, the rock surface has an average altitude somewhat lower than in the low plain in the vicinity of Chicago, for the majority of the wells reach a level about 50 feet below the surface of Lake Michigan before entering rock. It is estimated that the thickness of drift in this northern portion will average nearly 150 feet, while in the low plain the average will scarcely exceed 50 feet. The thickness of drift in the Indiana and ^Michigan portions is usually great, as has been indicated above. (See pages 302-393.) THE LAKE-BOEDER MOEAINIG SYSTEM. 407 STRUCTURE OF- THE DRIFT. The di-ift beneath the Ilhnois portion of these till plains, like that of the ridges, consists largely of a soft blue till, beneath which are remnants of a hard till of earlier age. The tills appear to be of direct glacial depo- sition, even in portions of the plain which lie within the limits of the beaches. The clayey matrix of the soft till seems to be less thickly set with stones than that of the underlying hard till, but in both tills many of the stones are glaciated and show little evidence of water abrasion. The rocky constituents grade from bowlders several feet in diameter down to minute pebbles. These, in the upper or later till, are made up In large part from the local upper Silurian rocks, probably less than 10 per cent being from the pre-Cambrian Canadian rocks. Frag-ments of Devonian rocks, apparently from ledg-es outcropping to the north of Chicago, are sparingly represented.' The clayey matrix is highly calcareous, and under the microscope it is found that angular or but slightly rounded grains of limestone constitute a large proportion of the fine material. With the minute limestone fragments there appear quartz grains, bits of shale, and fragments from crystalline rocks of various kinds. Whether the rock con- stituents of the older till diflPer markedly from those of the newer has not been ascertained. Its situation immediately upon the Lockport (Niagara) limestone would, in all probability, result in the incorporation of an even larger proportion of fragments from this rock than appears in the upper till. One of the most conspicuous instances of the occurrence of the lower till within this area is that brought to light in the excavation of the Chicago Drainage Canal. Immediately east from Summit the canal for about a mile extends a few feet into a very hard, partially cemented till, apparently of early glacial age. Its hardness compared with that of the overl}ang till is so marked that the contractors who engaged to excavate this part of the channel were obliged to abandon the steam shovel which had been used in the soft till and to resort to blasting. It is probable that this old di'ift fills depressions in the rock quite extensively in this district, but as no special attention has been given its identification the instances recognized are not ' On tbe microscopic structure of certain bowlder clays, and the organisms contained in them, by Dr. George M. Dawson : Bull. VI, Chicago Academy of Sciences. 408 THE ILLINOIS GLACIAL LOBE. numerous. The well drillers usually, distinguish the hard till from the over- Iving softer till and apply to it the name "hardpau," while the soft till is called clay. Although the great body of the drift is till, there are found numerous thin beds of sand or gi'avel in which water collects in sufficient quantities to supply the wells. There are also small pockets of dry sand or gravel occupying but a few cubic feet each. Such pockets were foiuid in the exca- vation of the main lake tunnel, and have been described b}- Dr. Edmund Andrews in a paper published in the American Journal of Science.^ They were in some cases completely inclosed by till. On the surface of the plain both above and below the upper beach there is quite generally present in Lake and Cook counties a clay in which pebbles are far less numerous than in the till; it, however, can-ies occasional bowlders. It rang-es in thickness from a few inches up to several feet. This deposit is perhaps a subaqueous till dropped in a body of water held between the ice front and the higher parts of the moi'ainic system while the ice sheet was still overhanging the inner slope. The depth of leaching and oxidation is markedly less on the plain covered by Lake Chicago than on the till ridges or the Valparaiso morainic system. Numerous acid tests show the leaching on the plain to extend only to a depth of a few inches, seldom more than 2 feet. On the till ridges the leaching is usually thorough to a deptli of 3 or 4 feet, while on the Valparaiso system it is rare to obtain a response with acid within 5 or 6 feet of the surface. On the plain and also on the till ridges the surface oxida- tion is usually but 3 to 6 feet, while on the Valparaiso system it is 6 to 10 feet or more. This difference in the amount of oxidation and leaching may be attributable in part to the more compact nature of the till ridges and plains, but it is probably in part due to the later date at which they became exposed to atmospheric action. There have been several deep lines of excavation made in Chicago and vicinity which have affoi*ded excellent opportunities for studying the struc- ture of the drift. Tlie longest line is the Drainage Canal, now imder con- struction, which ojjcns a channel 25 to 40 feet in depth from the Chicago River at Bridgeport to the Des Plaines River at Summit. Along the Des ' Atti. .lour. Rci., 2il scries, vol. 13, TRfiT, ]ip. 7.^-77. THE LAKE-BOEDEE MOEAINIO SYSTEM. 409 Plaines also the excavation is larg-ely in drift to the vicinity of Lemont, where the canal becomes a rock channel. From Bridgeport to Summit there is little besides till, but from Summit to Lemont gravel, sand, and the coarser material deposited or left as a residue along the line of the old lake outlet form a large part of the section. In the Fullerton avenue conduit, which leads eastward into the lake through the north part of Chicag-o, the drift is mainlj^ till, but surface sand is a conspicuous deposit. From its western end to within 2,000 feet of the lake the rock surface is found at a depth of 43 to 54 feet. Within 100 feet east from this point it drops down to 80 feet, passes below the conduit, and does not appear farther east. The surface sand has its greatest thickness at about 1,700 feet from the lake, where it reaches 25 feet. It decreases west- ward to only 12 feet at a distance of 6,000 feet from the lake, and entirely disappears before reaching- the Chicago River Valley. Toward the lake shore also it decreases, but holds a thickness of about 18 feet for 1,400 feet from the shore. At the water's edge the depth is but 10 feet. The profile continues out 1,100 feet beneath the lake, and there is but 3 feet of sand at its terminus Numerous borings and excavations in the south part of Chicago, in Hyde Park Township, show sand deposits ranging in depth from 5 feet or less up to about 20 feet. Till usually underlies the sand except where the rock comes near- the surface. In this connection it may be remai'ked that the heavy deposits of sand in Cook County are found chiefly along the present lake border from Evanston southward, where there is a continuous belt of sand ranging in width from one-half mile to 3 or 4 miles and having an average depth of not less than 10 feet. Over much of the plain west of this sandy belt the deposition was so light as scarcely to conceal the surface bowlders and in places leaves only a trace of sand in the soil. The south-westward lake outlet appears to have carried away much of the sand which was brought into the southern end of the lake while that outlet was open. , In the portion of Indiana between the Valparaiso morainic system and Lake Michigan sand deposits are heavj^ as far south as Calumet River in Lake and western Porter counties and nearly as far as the inner border of the till ridge in northeastern Porter and northwestern Laporte counties, a 410 THE ILLINOIS GLACIAL LOBE. belt whose width varies from scarcely 2 miles up to iully 5 miles. Where the duues are highest the sand probably has a thickness of about 200 feet, for the dunes attain a heig-ht of 150 to 175 feet, and the sand, as shown by wells, extends a few feet below the lake level. Throughout much of the belt the sand probably exceeds 25 feet in depth and may average twice that amount. South of Calumet River, from the mouth of Salt Creek, near Chrisman westward past Lake and Liverpool to Griffith, there is a belt of sand a mile or more in width which has generally a depth of about 20 feet. East from Salt Creek the depth is much less. The sand is also of slight depth west from Griffith except along the line of the beaches. Beneath this heavy deposit of sand there appears to be but little oxi- dized clay, a feature which favors the interpretation that the clay was not long exposed to atmospheric action before the sand deposition occun-ed. The wells usually pass immediately into a blue clay. This clay, so far as can be learned from well drillers, is but slightly pebbh' and appar- ently is in places free from pebbles. It seems to maintain this character to great depth, as is indicated by sections of wells already given. It differs markedly from the blue till of the neighboring portion of the plain in Cook County, Illinois, and appears also to be somewhat less pebbly than the blue clay of the neighboring district in southwestern Michigan. There are few exposures afforded by the streams in the district where sand is heavy, but exposures of slight depth are numerous outside the limits of the heavy sand. From these exposures it appears that the clay has gener- ally but few pebbles, and several exposures have been found in which it is pebbleless. The most extensive exposures of pebbleless clay noted are along Deep River, in the vicinity of Hobart, and it appears to be present over an area of several scjuare miles between Deep River and Salt Creek. Prof. W. S. Blatchley, State geologist, reports a similai- clay at Chesterton and Michi- gan City.^ This pebbleless clay is oxidized to a depth of a few feet, beneath wliich it presents a blue color similar to that of the ])ebbly clay of neighboring districts. It is highly calcareous and carries numerous lime- stone nodules near the bottom of the oxidized portion. It seems even more calcareous than the pebbly blue clay. Professor Blatchley has published 'Coinmnnicated to tlio writer. THE LAKE-BOEDER MORAINIC SYSTEM. 411 the following analyses of samples of these pebbleless clays, made by Prof W. A. Noyes. of Terre Haute, Indiana.^ Analyses of clays of Pleistocene age. Hobart. Garden City. Chesterton. Michigan City. Silica - Per cent. 50. 56 1.00 13.11 2.76 Per eent. 50.37 .65 9.93 1.50 Per cent. 53.02 1.30 10.72 2.21 Per cent. 50.47 1.45 12.77 3.14 Combined water . Total clay V)a8e and sand . . . i^erric oxide -. , _-.- 67.43 62.45 67.25 67.83 2.98 2.32 7.87 5.06 3.74 .70 2.10 2.05 10.26 6.26 3.04 .79 2.54 2.22 8.38 5.28 3.25 .86 2.44 2.52 8.17 5.22 3.70 .73 Ferrous oxide . Soda Total fluxes 22.67 9.62 24.50 12.50 22.53 10.48 22.78 9.80 Carbon di oxide Total 99.72 99.45 100. 26 100. 41 In explanation of the contrast in the amount of coarse material in the clays bordering' the lake in northwestern Indiana, compared with those in Cook County, Illinois, it may be remarked that it is probable that the char- acter of the underlying rocks will prove an important factor. In Cook County, Illinois, the underlying rocks are the somewhat resistant Lockport (Niagara) limestone, while in the neighboring portion of Indiana the rocks immediately beneath the drift are the Devonian shales, which are easily com- minuted and ground into a clayey material. It is probable, however, that the conditions of deposition were slightly different in the two districts. In Cook County the southwestward line of discharge may have been open sufficiently to allow a considerable part of the fine material to be carried down the Des Plaines Valley, while in the Indiana district it may all have been deposited without much transportation or sifting out of the finer material. The localities where the pebbleless clay are best exposed are beneath the bay-like extensions of Lake Chicago, and may possibly be 1 22d Ann. Kept. Indiana Geol. Survey, 1898, pp. 128, 134, 1.S7, and 139. 412 THE ILLINOIS GLACIAL LOBE. composed of sediment wliich settled in the waters of the bays. The g-reat amount of calcareous material, however, seems to indicate that they are a glacial rather than lacustrine silt. The scarcity of evidence of life in the earh' stages of the lake seems to indicate that but little calcareous material can be looked for from that source. SECTION VI. STRIDE WITHITs^ LIMITS OF SHEIiBY^'ILIiE MORAIXE. The table of stria; given below includes all exposures of which the writer has knowledge either through personal observations or from publica- tions and correspondence. There are several observations taken by Messrs. J. T. Campbell, 0. P. Jenkins, A. H. Purdue, and J. A. Udden, hitherto unpublished, which have been kindly contributed for publication in this report The bearings taken by the writer, except when so designated, are not corrected for magnetic variation. The bearings taken in western Indiana by Collett, Campbell, and Jenkins are corrected for magnetic varia- tion, but so far as known all others are magnetic. The magnetic variation in western Indiana is only about 3° east and in western Illinois 6° east.^ TaMe o/stj-ue within limits of Shelby ville moraine. Location. Bearing. Observer. Near Troutman, lud 8.8'=' E Collett. Coal Creek bluff, 3 miles west of Wayueto-n-n S. 18° E Collett. Coal Creek bluff, 3 miles west of Waynetown a S. 20° W Hopkins. Near Darlington, Ind S. 31° E Leverett. Near Darlington, Ind. b S. W Thompson. In northern Parke Connty, sec. 27, T. 17, R. 7 W ; 8.39° 48' E ' Campbell. In northern Parke County, see. 27, T. 17, E. 7 W o ' 8.34° 30' E ' Campbell. Williamsport, Ind ' S.68° E ! Leverett. Williamsport, Ind. if ' S.8°-10° W ... Salisbury. a See Collett, Geol. of Indi.ina 1875. p. 370. Also Hoiikins, Geol. of Inrti.ina, 180.i, p. 273. Tlie observations by Mr. Hopkins indicate that the bearing reported by Mr. Collett should be S. 18° W. b The stria' reported by Mr. Mauriee Tboiupsim were probably formed by the Krie lobe. c Two exposures on the bluflf of Sugar Creek. 100 feet apart, show a difterence of 5^ in bearing. The observer, Capt. J. T. Campbell, of Rockville, Indiana, has reported several exposures of glacial strirt' in Parke and Putnam counties, Indiana, which bear soiithwestward, and accordingly are referred to the Alauniee lobe. They are discussed in alinther report now in jireparation. d The observations reported by Professor Salisbury probably represent a inovemeut connected witll the "Wisconsin stage c(f glaciatitui. wbile the observations reported by the writer belong apparently to an earlier glaciation. Two miles east of Williaiiispiirt, on the north side of tlie "Wubash, Professor Cbamberliu found a tliird set of stria^ with westward bearing, which appuroutly pertain to the invasion of the Erie lobe. (See Seventh Annual Keport f. S. Geol. Survey, p. 207.) ' See map of Henry (lannett, showing distribution of magnetic variation in the United States for the year 1900: Seventeenth Ann. Kept. U. S. Geol. Survey, Part I, PI. II. STELE WITHIN LIMITS OF SHELBYVILLE MORAINE. Table of strue within limits of Shelbyville moraine — Continued. 413 Location. Near Fountain post-ofBce, iu sec. i, T. 20, R. 8 W., main bearing. Near Fountain post-office, in sec. 4, T. 20, R. 8 W., scatter- ing stri;e. Logansport, lud., on banlv of Eel River East of Logansport, on bed of Eel River Mouou , Ind Mouou, Ind. a - Rensselaer, Ind Quarry, near Kentland Quarry, near Kentland a South bluflf of Illinois Elver, near Lasalle Mazon Creek blnif, sec. 30, T. 33N., R. 8E Near Morris, 111., iu sec. 24, T. 34, R. 7 E Near Morris, 111., iu sec. 19, T. 34, R. 8 E Near Morris, 111. , in sec.l8, T. 34, R. 8 E .' Near Morris, 111. , iu sec. 18, T. 34, R. 8 E In Lisbon, 111 Aux Sable Creek, west of Minooka Aux Sable Creek, sec. 9, T. 35, E. 8 E Brodie's. Quarry, on Fox River bliitf, north of Millington, III.. Little Rock Creek, sec. 33, T. 37, R. 6 E. See. 34, T. 37, R. 6 E Sec. 1,T.37, R.6E Joliet, near penitentiary Dupage River blnif, at crossing of Chicago, Rock Island and Pacitic R. R. Kankakee River blufi', in sec. 9, T. 33, R. 9 E Near Wilmington, 111., in sec. 31, T. 33, E. 10 E Beckford's Quarry, sec. 10, T. 33, R. 11 E Lemont, near Des Plaines "Cut-off" Between Willow Springs and Sag Bridge West of Summit North of Summit, near Santa Fe railway bridge , Bearing. S. 40° E , S.56°-620E ... S. 14° E. or N. 14° W. S.58° W S.34C E S. 85° W S. 8°-14° W... S.70E S.77-W S.75°W S.44°W S. .50°-55° W.. S. 60° W S. 30°-38° W - . S. 40°-55 W... S. 50° W S.W S. 47°45' W... S. 9° 30' E. to S. 27° 30' W. S. 31° AV., S. 37° W., S. 40° W. S.42°W S. 110° 30' W . S.96°W S. 42° 30' W . . S. 58° W . S..43° W . S.31°W., S. 60°W.. S. 18°W., S.34°W. S.86°W. Observer. Siebenthai. Siebenthal. Leverett. Leverett. Chamberlin. Chamberliu. Purdue. Chamberlin. Chamberlin. Leverett. Leverett. Leverett. Leverett. Bradley. Leverett. Leverett. Udden. Leverett. Leverett. Leverett. Leverett. Leverett. Leverett. Udden. Leverett. Leverett. Leverett. Guthrie. Leverett. Leverett. Leverett. ftAtMononand near Eentland there are two .system.s of strife reported by Professor Chamberlin. In the latter instance the southward pointing stripe lie in grooves and furrows in the limestone, while the "westward pointing striae only aiJect the crests of these furrows, which have been slightly truncated by tlie later westward movement. (See Seventh Annual Report U. S. Geol. Survey, p. 207.) The writer made an observation of striae 2 miles east of Kentland, iu which they appear at various angles between S. 4° E. and S. 75° W., in such manner as to suggest that more than two movements affected the rock ledge. 414 THE ILLINOIS GLACIAL LOBE. Table of stria' within limits of SlielbyviUe moraine — Continued. Location. Bearing. Observer. T.ivnns in T)es Plaines A'^allev .- .. - S. 40- W. to S. 6T^ W. S.54°W S 67- W Leverett. Leverett. East of Elmburst, in sec. 17. T. 39, R. 12 E Hawthorne quarries, west })art of Chicago Quarry at Western and Chicago avenues, Chicago Piinprton avenue conduit Chica*^o S.58^-\V S. 60^-64= W--. S.68°W S.60=W S.480-55-AV.-. S.30°-oO=W... R.oO-AV Leverett. Leverett. Leverett. Citv engineer. Quarry at Eighteenth and Robey streets, Chicago Stonv Tsla.iid.. South Chica^'o Leverett. Leverett. Leverett. Gnthrie. Leverett. Blue Island iiuarries, 2 miles soutUvrest of village Thornton, in valley east of village a E.-W S.27-W ffiilr. Ossian Guthrie reports having observed strise at Thornton bearing more nearly westward. {See Guthrie's pamphlet on the Lake Michigan Glaciers, map 3.) Considerable difficulty i.s experienced in assigning stria? in northwestern Indiana to tlie proper ice lobe. That district was invaded from the north- ward by the Illinois lobe and subsequently from the eastward by another portion of the ice sheet, the Saginaw-Erie lobe, which in the closing stages of glaciation became differentiated into the Siiginaw lobe and the Erie or Maumee lobe. Accordingly both southward and westward bearing strise are found. In some places, as at Monon and Kentland, a single rock sur- face presents both southward and westward bearing stria?, the west^^'ard beino- the later. Usually, however, the sti'ite formed by the earlier ice movement were either protected by drift deposits from the action of the later ice movement, or they were so exposed as to be effaced by tlte later movement. There are strise on the north bank of Eel River in the city of Logans- port, concerning which the direction of movement is not certain. The bearing is N. 14° W. or S. 14° E. Immediately north of Logansport lies a heavy moraine formed on the north border of the Erie lobe, wliich, as just noted, extended westward from the Lake Erie Basin. We may sup- pose the stria' to have been formed h\ ;i northward movement toward this moraine, but it is quite as probable that tliey were formed by an earlier soutliward movement, independent of the moraine and perhaps referable to STEI^ WITHIN LIMITS OF SHELBYVILLB MOEAmE. 415 the Illinois lobe. A careful examination of the striated surface failed to disclose decisive evidence whether the movement was northward or southward. It may be remarked in this connection that just above the city of Logansport the bed of Eel River shows heavy glacial grooves bearing S. 58° W., which are evidently the product of the movement from the Lake Erie Basin. It seems scarcely possible for the same ice movement to produce, within the limits of a single township, striae with bearing differing 108 degrees, and that too in a comparatively smooth region. But so little is known as yet concerning the possibilities of ice movement, that judgment should perhaps be reserved. The striae of northeastern Illinois show some interesting deviations from a general southwestward course. In the Des Plaines Valley there is a rr.nge from S. 18° W. to S. 96° W. Three observations between Summit and Lemont show bearings S. 34° W., S. 18° W., and S. 60° W. The stria; bearing nearest westward are accompanied by heavy grooves which seem to call for the action of a thick ice sheet, but the other exposures show oidy faint striation, and it has occurred to the writer that jJossibly this faint striation is attributable to masses of ice floating down the valley after the ice sheet had withdrawn. Another locality in northeastern Illinois, where the striation is thought to be referable to floating ice, is on the bluff of Fox River, north of Millington, in Kendall County, where faint striae occur with bearings ranging from S. 9° 30' E. to S. 27° 30' W. In a great majority of exposures in the Illinois district glaciation is heavy, with complete planing of surface and often with heavy grooves, and can scarcely be referred to floating ice. At Joliet striae were observed with bearing slightly' north of west, but this bearing is almost at right angles with the trend of the Minooka till ridge a few miles west of Joliet, and is probably referable to the ice move- ment which produced that ridge. The same explanation probably should be given for the bearing 20° north of west, shown in an exposure a few miles west of Aurora (sec. 1, T. 37 N., R. 6 E.), for a moraine with NE.-SW. trend passes through the distiict immediately northwest of these striae. On Stony Island, in the south part of Chicago, the rock quarrv where glaciation was observed has beds which dip toward the southeast with an angle of 30 degrees or more. Heavy scorings follow the line of strike, with 416 THE ILLIJTOIS GLACIAL LOBE. a bearing S. 44° W. Associated with these are strire of feebler develop- ment, wliich vary in direction fully 10 degrees to the east and west of the heavy scorings, thus ranging from S. 34° to S. 54° W. An escarpment of the dipping layers which rises about 6 feet above the remainder of the quarry is glaciated not only on the upper surface and nearly vertical front, but also beneath one of the lower layers, its dipping imder surface being smoothly polished for about 18 inches back from the front of the ledge. A Fig. 2. — Glaciated surface iu bed of Chicago drainage canal. [Drawing from a photograph taken by Chicago Drainage Commission.] photograph of this ledge has been furnished by the Chicago Academy of Sciences (see PL. XVI). A glaciated surface exposed near Lemont in the excavation of the Chicago drainage canal is represented in fig. 2, which has been drawn from a photograph taken Ijy the Chicago Drainage Commission. The fuiTows are remarkably direct for a distance of several rods, and the planing is exceptionally smooth. In the vicinity of T^eniont the bed of the Chicago Outlet is extensivelv clianneled by nearh' parallel grooves several inches in width and depth and STEI.E WITHIN LIMITS OF SHELBTVILLE MOEAINE. 417 many rods in length. A photograph of an exposure made in the diversion channel of the Des Plaines is here furnished through the kindness of the Fig. 3.— Grooves exposed by canal in bed of Chicago Outlet near Lemont, Illinois, apparently due to abrasion by pebbles transported by water in the outlet rather than to glaciation. [Drawing from a photograph by Chicago Drainage Commission.] Chicago Drainage Commission (see fig. 3). These channels were announced in the Chicago newspapers to be glacial grooves, but thej^ are aj)parently due to water abrasion rather than glacial scoring. MON xxsviii 27 OHAPTERXI. THE CHICAGO OUTLET AND BEACHES OF LAKE CHICAGO. PREVIOUS WRITERS. It is perhaps impossible to determine who was the first person to recog- nize the evidence or form the conception of a southwestward outlet from the Lake Michigan Basin to the Des Plaines Valley. Inquirj^ among the old residents of this region shows that many of them recognized the beaches as prodiicts of the lake, and they also noted that the lake once discharged into the Des Plaines Valley. Evidently these conceptions were entertained for many years before any notice appeared in scientific publications. Bannister. — Probably the earliest scientific account of the outlet is that given by Dr. H. M. Bannister, in 1868, in the Geology of Illinois.^ How- ever, a report by the U. S. Army Engineers upon the survey of the Illinois River, by Col. James H. Wilson and William Gooding, was published the same year, which makes reference to the former southwestward discharge of Lake Michigan. Dr. Bannister opens his discussion of the old lake outlet and the raised beaches with the following statement: It is evident with a very little observation that, at a comparatively recent period, subsequent to the Glacial epoch, a considerable portion of Cook County was under the waters of Lake Michigan, which at that time found an outlet into the Mississippi Valley through the present channel of the Des Plaines. Andrews. — (.)ne of tlie early publications of the Chicago Academy of Sciences presents a discussion of the beaches by Dr. Edmund Andi'ews, which has attracted wide notice.- The ])aper, however, deals mainly with the work of the lake at its present stage. The ancient beaches are briefly ' Geol. of Illinois, Vol. Ill, 1868, \>V- -''10-242. -Tlie North Americau lakes considered as elironoiiietei's of post-GIacial time, by Dr. Edmund Andrews: Trans. Cliicigo Academy of Scieuees, Vol. II, 1870, article 1, p]). l-L'4. 418 THE CHICAGO OUTLET. 419 discussed, but the outlet is not described. A map accompanying the paper shows the approximate extent of the old lake beyond its present limits from the southern end northward some distance into Wisconsin and Michigan. chamberiin. — Prof T. C. CliamberKn presented a brief discussion of the beaches along the "Wisconsin shore of Lake Michigan in the Greology of Wisconsin,^ which includes many important data concerning the shore j)henomena and an interpretation of the lake history. In the twenty years which have elapsed since that report was published, the studies of the shores of the Grreat Lakes have brought out a more complex history than had been anticipated; hence the interpretation does not fully meet the case, though it recognizes important fluctuations of lake level. Leverett. — Although, subscqueut to the publications just noted, there have been frequent references in geological literature to the southwestward outlet and the ancient beaches, no publication especially devoted to them appeared until 1888, when a paper was published by the present writer in the Trans- actions of the Wisconsin Academy of Sciences.^ This paper gives a somewhat detailed account of each of the several beaches found south of latitude 42° 30', the latitude of the hue of Wisconsin and Illinois. It contains but a brief reference to the outlet.^ cooiey. — Prof. L. E. Cooley, consulting engineer of the Chicago Drain- age Commission, has published two papers which deal to some extent with the Chicago Outlet.* The first paper discusses the outlet as a means for improving the sanitary conditions at Chicago. The second paper deals with it as an important line for navigation, and discusses the proper means for obtaining the best results This paper contains a large amount of valu- able data concerning the regimen of the Illinois and Des Plaines rivers. Marshall. — The report of the United States Army Engineers for 1890 contains much valuable material collected by Capt. W. L. Marshall con- cerning the Chicago Outlet as a channel for navigation; also references to earlier work by that organization. 'Geology of Wisconsin, Vol. II, 1877, pp. 219*-233. -The raised beaches at the head of Lalie Michigan, by Frank Leverett: Trans, of Wisconsin Acad, of Sciences, Vol. VII, 1883-1887, pp. 177-192. Published in 1888. ^ It should be explained that the numerous typographical errors in the paper are due to the fact that the writer had no opportunity to correct the proof. ■" Water supplies of Illinois in relation to health : Report of the Illinois State Board of Health, 1889. Lake and Gulf Waterway. Private publication, 1891. 420 THE ILLINOIS GLACIAL LOBE. Taylor. — Ml'. F. B. Tavloi" lias published in the American Geologist obser- vations on liig'li beaches in the northern poition of the basin of Lake Michi- gan.^ These beaches, he thinks, pass beneath the present lake level before reaching the southern end of the basin. This being the case, they have no connection with the outlet under discussion. Davis. — Prof W. M. Davis has published a description of the Chicag-o Outlet in the Popular Science Monthly." His paper was based upon a per- sonal inspection of the channel with the United States topographic sheets in hand, and is a very clear, though brief, discussion of the features. THE CHICAGO C)lTTt,ET.' The name ' ' Chicago Outlet " has come into use by geologists and engi- neers, without definite announcement or conference among writers, to desig- nate the line of southwestward discharge from the basin of Lake Michigan across the low divides near Chicago and thence down the Des Plaines and Illinois to the Mississippi. It may appropriately embrace both points of discharge from the lake to the Des Plaines — namely, the one entering at Summit and the one at Sag Bridge. When the lake was occupying the highest beach, the north or maiil outlet was entered about 3 miles southwest of Summit; when occupying the second beach, the outlet was entered at Summit; when occupying the third beach, the point of entrance appears to have been transferred eastward nearly to the present shore of Lake Michigan, as explained below. Simi- larly the southern outlet was lengthened eastward with the lowering of the lake, the point of entrance at the time of the highest beach being about 5 miles east of Sag Bridge, at the time of the second beach near Blue Island, and at the time of the third beach at Riverdale. This relationship of the several beaches to the outlets and the eastward lengthening of the outlets may be readily understood by a glance at the accompanying map (PI. XVII). There have been several surveys which have contributed contour maps of portions of the Chicago Outlet and of the plain covered by the lake in the vicinity of Chicago. The Chicago Drainage Commission have prepared an excellent map with 5-foot contours which covers nearly all of Cook ' American Geologist, Vol. XIII, May, 1894. ^Tlie aucieut outlet of Micliigaii, by Prof. W. M. Bavis: Pojuilar Science Monthly, December, 1894, pp. 218-229. U.S. GEOLOGICAL SURVEY. MONOGRAPH X X X V I 1 I PL. XVH LIST OF CITIES AND VILLAGES. GLACIAL MAP OF CHICAGO AND VICINITY. By Fbank Leyekett. 1897. NOTE. — The topography ia indicated by brofeen profiles, the straight lines represent- ing plains, and the curved lines rolling country. With the exception of dimes and sandy beaches on the border of Late Michi- gan the rolling siirface represents moralnic topography. 1 WaukegaD 2 Gurnee 3 Hainesville 4 Fort Hill 6 Volo 6 Wauconda 7 Fremont e Ivanhoe 9 Diamond Lake 10 LibertyvIUe 11 Kondout 12 LaVe Forest 13 Highland U Ravin ia 15 Deerfleld 16 HalfDayP. O. 17 I>ake Zurich 18 Barriutrton 19 Palatine 20 ArlinEtonHolKhtB 21 Wheeline 22 NorthfleW 23 Oak Glen 24 Glencoe 25 "Winnetka 26 Wilmette 27 Evanston 28 Miles 29 Park Ridge 30 Des Plalnes 31 Mount Prospect 52 Sebaumberg 33 Eartlett 34 Spaulding 35 Wayne 36 Ontario 37 Boselle 36 Itasca 39 Eensonvllle 40 Tamer Park 41 Austin 12 Oak Park 43 Riverside 44 May wood 45 Elmhurst 4fi Lombard 47 GrlenEllyn 48 Wheaton 49 Turner .lunotion soEola 61 Naperville 62 Downers Grove ft3 Hinsdale 54 Western Springs 55 La Grange 56 Willow Springs 57 Summit 53 Morgan Park 59 Bine Island 60 Worth 61 Sag Bridge 62 Lemont 63 Komeo 64 Plainfleld 66 Lock port ee Hadley 67 Orland 68 Bremen 69 Homewood 70 Harvey 71 Thornton 72 Hammond 73 Whiting 74 Gibson 75 Hessvilie 76 Griffltb 77 Edgemoor 73 Clark 79 Miller 80 Wilson's 81 Hobart 82 Wheeler 83 Crown Point 84 ShermerviUe 85 St. John 86 BrUDSwiek I Fi HE t nAdt- I ^' •"'" R^'3g\' T 'R-I.4-E:. isi5ek.r6wl' " 'r'Tw '~ TOPOGffAPHr OEL.erW^At-a. THE CHICAGO OUTLET. 421 County, and the immediate borders of the Chicago Outlet along the Des Plaines River. This has not been published, being merely a study map. The topographic work carried on by the United States Geological Survey in this region is largely published. The peculiar features of the upper por- tion of the outlet are brought out in an effective manner by the following sheets, ^n.z, the Chicago, Riverside, Calumet, Des Plaines, Joliet, Wilming- ton, Monis, Ottawa, Marseilles, Lasalle, Hennepin, and Lacon sheets. These sheets cover something over 100. miles of the former lake outlet, or nearly one-third the distance from the head of the outlet to the Mississippi. The remainder of the outlet is shown in Prof C. W. Rolfe's map sheets, yet unpublished. The reduced contour map (PL III) accompau3:'ing this report is based upon these several surveys. It serves to indicate the comparative size of the valleys occupied by the outlet and of the main tributaries of the Illinois. But to fully appreciate the features produced by the outlet, refer- ence should be made to the lai'ge scale maps just mentioned. In the interpretation of these features from the maps, care must be exercised in determining the condition of the valley at the time the outlet first became operative. The portion of the Illinois below Hennepin, it will be observed, is a preglacial valley, and was only partially filled by the glacial deposits. This filling is preserved in terraces along the borders of the valley. The glacial terraces seldom rise to a height of more than 100 feet and in the lower 100 miles their average height scarcely exceeds 50 feet above the present sti-eam. In the portion of the valley above Hennepin the stream is mainly in a glacial or postglacial course, but even here there are complications which make it no easy matter to determine the amount of erosion attributable to the outlet. Before the accession of the lake waters this valley was the line of discharge for streams issuing from the ice sheet, as possibly of interglacial streams, some evidence of which has been gathered both by Professor Chamberlin and the writer. Although the streams were generally so heavily charged with detritus as to build up rather than erode their beds for some distance below the point of emergence from the ice sheet, it seems scarcely probable that filling would have exceeded erosion tlu-oughout the entire length of the. Des Plaines and Illinois valleys. The basin at the head of the Illinois, as noted above, was apparently occupied by a lake at the Valparaiso substage of glaciation, and this would have received the greater part of the detritus borne down by the 422 THE ILLINOIS GLACIAL LOBE. glacial floods on the Des Plaines and other tributaries entering the basin farther east, thus permitting the water to issue at the western end of the basin, unburdened with glacial material. The stream discharging westward from this basin would, therefore, have a tendency to deepen the new valley opened across the Marseilles moraine, and in all probabilit}' would have extended its excavation at least through the new portion of the valley to Hemiepin, there being in that section a gradient of several inches per mile and possibly at first a higher gradient. It seems not improbable, also, that some excavation was accomplished by the glacial floods in their passage over the terraces in the lower portion of the Illinois Valley, the advantages for erosion being as good for these floods as for the later ones fed by Lake Chicago. It is also necessary to estimate the amount of filling which the lower course of the outlet has received since the lake waters were withdrawn. Concerning this filling. Prof L. E. Cooley has made some investigation and concludes that from Peru to Peoria it will average 30 feet, and is appreciable to the mouth of the Illinois, though probably somewhat less toward the mouth of the river.^ In the Des Plaines Valley the erosion of the Valparaiso moraine and of the tei-races outside of it was probably very largely effected by the lake waters. An examination of this portion of the outlet will therefore be likely to afford a fair understanding of the size of the channel which it formed. From the topographic maps it appears that the bed of the lake outlet declines from about 51^)0 feet at Lemont, in the midst of the Valparaiso system, to scarcely 500 feet at the head of the Illinois, or 90 feet in a distance of 25 miles. Of this fall, 76 feet is made in a little less than 10 miles, from Romeo to Joliet pool. The glacial terraces which border the outlet decline from about 630 feet to 570 feet between Lemont and the liead of the Illinois. This deepening of the channel is shown by the maps to be somewhat irregular, ranging from 40 feet to about 70 feet, but an average erosion of 50 feet ma}' be assumed. This deepening embraces not only the work at the time the upper beach was forming, but also that carried on during tlie tonuation of tlie second and tliird beaches, or down to the time of the final abandonment of tlic lake outlet. Tlic chamiel above Joliet has ' Couiuiiuiiciitcd to tliu writer. THE CHICAGO OUTLET. 423 a breadth of 1 to IJ miles, averaging perhaps 1^ miles. Between Joliet and the head of the Illinois several island-like remnants of the glacial terraces are preserved in the midst of the channel, making it more difficult to estimate the Ijreadth, but it is not markedly greater than in the portion above Joliet. The portion above Joliet is cut to a slight depth into the Lockport (Niagara) limestone, which there underlies the glacial gravel. The excavation in limestone, however, amounts to not more than one-fourth the size of the channel, for the limestone seldom rises more than 40 feet above the bed of the lake outlet, and in many places its surface comes down nearly to the level of the valley floor. Below Joliet there was even less excava- tion in the rock than above. It is estimated that the rock excavation there does not exceed 10 per cent of the total cutting. In the low tract at the head of the Illinois (the Morris Basin) the depth of the excavation by the outlet is very slight, averaging ]3robably less than 20 feet in the 10 miles between the head of the Illinois and Morris. The plain appears to have descended nearly to the 520-foot contour on the borders of the river before modified at all by lake or stream action. A low bluff formed on the north border of the basin has a height of 15 to 20 feet. On the south border there is no bluff, that side of the basin being heavily coated with sand deposits. These deposits may perhaps have been laid down in part at the time the lake waters were forming the outlet, but they are probably largely of earlier date. In this basin the lake outlet has an average width of 4 or 5 miles. In the section of the Illinois immediately below (west from) this basin, erosion prior to the opening of the Chicago Outlet jJi'obably had brought the level of the valley bottom down to that of the upper beach line of the basin, 550 to 560 feet above tide. The bed of the Chicago Outlet is nearlj^ 500 feet, thus leaving about 60 feet subsequent depth of erosion. Passing westward the broad bed of the Chicago Outlet declines nearl}- 60 feet in the 40 miles between the west border of the basin, just mentioned, and the bend of the Illinois near Hennepin. Whether the valley had the same gradient at the time the accession of lake waters occurred is not known, but it could not have been greatly diflFerent, for the glacial terrace just above Hennepin stands about 30 feet lower than the beach lines of the Morris Basin, and this terrace in all probability had been eroded the remaining 30 to 40 feet neces- sary to give a similar gradient. 424 THE ILLINOIS GLACIAL LOBE. The width of the outlet between Mon-is and Hennepin averages about IJ miles. The excavation is largely in soft St. Peter sandstone, there being nearly continuous rock bluffs to a height of 60 to 75 feet above the level of the bed of the outlet. This sandstone and the Coal Measures sandstone which in places overlies it present much less resistance to sti'eam action than the tirni Loekport (Niagara) limestone. The resistance may not be markedly gi-eater than that of the beds of glacial drift. As noted above, the level at which excavation by lake waters began in the section below the great bend of the Illinois is less than 1 00 feet above the present stream, since the glacial terraces in which the lake outlet was excavated seldom reach a level 100 feet above the bed of the outlet, while below the mouth of the Sangamon they rise scarcely 50 feet above that level. If the 30 feet of filling estimated by Professor Cooley be added, it seems a liberal estimate to allow 75 feet of average excavation in this lower section of 200 miles. It may not have been more than two-thirds that amount. The width of the outlet in this lower section ranges from 2 up to about 5 miles, with an average of perhaps 3 miles. This excavation is in a loose, easil}^ eroded bed of sand and fine gravel, which had been deposited largely by glacial streams. Summing up the above estimates, it appears that the outlet has a width ranging from 1 mile up to about 5 miles, and a depth ranging from 20 feet up to 70 feet. Its length from Summit to the mouth of the Illinois is 300 miles. The excavation is probably not less than 3 cubic miles. With the exception of about 15 miles between Lemont and Joliet and 40 miles between Morris and Peru, where rock strata have been eroded, the excava- tion is almost entirely in beds of drift. The width varies -with the resist- ance to erosion, being least in the section where the resistant limestone was eroded and greatest where there were only drift beds to remove, while in the sandstone the channel is of intermediate breadth. The breadth is also to some degree dependent upon the slope of the bed, being narrower in the portions with rapid fall than in portions having a low rate of descent. Throng] lout the entire length of the outlet the bluffs are steep, like a river bank, and deposits made by side streams on the edge of the valley are very meager — ii feature which indicates that the stream had great vol- ume, probably filling the channel from bluff to bluff, and a current suffi- THE CHICAGO OUTLET. 425 ciently strong to cany away nearly all the detritus brought into it by the side streams The rapids between Romeo and Joliet occur in a section where the limestone is friable, and it is thought b}' Professor Cooley that the friability is such that falls could not have been maintained, or even established. The removal of the existing rapids, the main barrier in the course of the outlet, it is estimated, would require the excavation of a channel in rock only about 20 miles in length and 26 to 75 feet in depth. This excavation would be about ten times that accomplished by the lake outlet in that part of its course. Being the outlet from a lake, the amount of sediment carried by its waters is a matter which should be weighed in discussing the slight amount of excavation. Professor Cooley has called the writer's attention to the deposits at the head of Lake St. Clair as likely to furnish an index of the amount of sedi- ment transported by the Chicago Outlet. A delta with an area of several square miles .has been built in the head of Lake St. Clair, which must have derived the bulk of its material from southward-moving littoral currents along both the borders of Lake Huron. In the lake under discussion littoral currents along the west border would have transported material probably in as great volume as on either shore of Lake Huron, but those on the east and south may have contributed less, for wind drifting there is very effective. It seems legitimate to assume that at least half as much sediment was being transported down the Chicago Outlet as is carried by the St. Clair River. From this it appears probable that the waters of the Chicago Outlet were somewhat less turbid than the St. Clair. Professor Cooley thinks the contributions of sediment to the outlet through the Des Plaines were of little consequence, for this river has, since the lake waters were withdrawn, made scarcely any filling of the outlet below Riverside, where its delta would naturally accumulate. The accession of larger tributaries below may have rendered the stream slightly more turbid than on the rapids It should not be inferred that this outlet is entirely free from river debris. Beginning at the upper beach, near Summit, there is for several miles a mass of coarse material, largely limestone blocks, too large to have been transported by the current, covering the bed of the outlet. The Drainage Canal exposes excellent sections of the coarse river ddbris from Summit to Lemont, there being' only limited areas in this interval where 426 THE ILLINOIS GLACIAL LOBE. the solid rock comes to the siu-face. Below Lemont the bare I'ock forms much of the floor as far as Joliet. From Joliet to the head of the Illinois perhaps half the floor is covered with deposits of drift and river deVjris, so that the distance to rock is not known. The remainder is either bare rock or rock with a very thin deposit of coarse river debris, with a liberal sup- ply of bowlders of Canadian derivation. In the ^Morris Basin the rock is largely shale. This has been eroded in places by the current, and the hol- lows have been tilled with sand. From the Morris Basin to the bend of the Illinois the rock floor, mainly sandstone, is generally swept clean. The St. Peter sandstone of this section is of such a texture as to break up rap- idly into its constituent grains, and these, as fast as they were set free, would have been carried by the strong current down to the lower Illinois, and probably on into the Mississippi. The lower Illinois has onlv sand and silt in its bottoms. This section is now in process of silting up, the current being too slugg'ish to carry away the material brought in fi'om the upper portion of the stream. Accumulations of bowlders should be mentioned in connection with the river debris. The most conspicuous accumulation noted is that on the borders of the Sag outlet, just east of the point where it enters the ^'alpa- raiso morainic system and northeast of the village of Worth. An area of perhaps a square mile is so thickly strewn that one might almost step from stone to stone over its entire extent. There are, it is estimated, more than i,000 bowlders per acre. Surface bowlders are not rare in otlier portions of the old lake bottom where sand deposits are thin or wanting-, there being, perhaps, 200 per square mile on the part of the lake bottom where till is exposed. There seems, however, to l)e a tendency to aggregation at the entrance to the old outlets. This feature sug-gests that floating ice has been influential in their distribution, though there mav have been a large number brought by the ice sheet, the head of the outlets being near the inner border of the Valparaiso morainic system. Some very large bowlders have been fcund along the Drainage Canal. The large ones occur in most abundance where the Valparaiso system is crossed by tlie lake outlet. Bowlders are also very numerous for a few miles above the junction of the Des Plaines with tlie Kankakee. They seldom reach tlie large size which bowlders in the Valparaiso svstem present. THE ILLINOIS GLACIAL LOBE. 427 THE GliACIAIi LAKE CHICAGO. The uame "Lake Chicago" was introduced by the writer in a recent bulletin issued by the Chicago Academy of Sciences.-^ The need for a name for this glacial lake and the reason for the selection of this name are set forth in the following statement: - The introduction of the name " Lake Chicago" for the glacial lake which was held in the southern end of the Lake Michigan Basin seems convenient, if not necessary, inasmuch as its area was not coincident with that of Lake Michigan and its outlet was in the reverse direction. It is also in keeping with the custom of students of glacial lakes, who find it advantageous to employ a special name for each of the temporary bodies of water in the several basins. The name "Lake Chicago" seems especially pertinent, since the glacial lake extended about as far beyond the present limits of Lake Michigan in the vicinity of Chicago as fit any part of its border. It is also a name which readily suggests the position of the lake, and it is in keeping with the name which has conu^ into use for the outlet, namely, the "Chicago Outlet." The name " Lake Chicago " is a))i)Ued provisionally to all the stages at which there was a southwestward outlet, but it is not yet certain whether they were all formed during the occupancy of a portion of the Lake Michigan Basin by the ice sheet. The precise relations of these beaches to the ice sheet, or points of connection with it, have not as yet been determined. The writer's study has been carried no farther north than to the line of Wisconsin and Illinois on the west side and to Grrand River on the east side of Lake Michigan. Professor Chamberlin's studies left the precise extent of the higher beaches undetermined. Mr. Taylor's observations have been confined to the north- ern portion of the basin, and as yet no one has examined the intervening districts, whei'e it appears probable that the higher beaches terminate. Probably the most favorable field for investigation will be found on the Wisconsin side, since extensive deposits of wind-drifted sand on the border of the lake in Michigan make it difficult to determine the extent of water action. The long stretches of high bluff, however, interrupt the beaches so greatly that some difficulty is anticipated in making precise correlations on the Wisconsin side. Enough is known to make certain that the general direction of retreat of the ice sheet was northeastward. The southern and western jjortions of the Great Lake basins were, therefore, the first to become free from ice and ' The Pleistocene features and deposits of the Cliicago area, by Frank Leverett : Bull. No. 2, Geo), and Nat. Hist. Survey, Chicago Academy of Sciences. Issued May, 1897. "Op. cit., p. 65. 42r< THE ILLINOIS (iLAGlAL LOBE. to be occupied by glacial lakes. While the ice sheet was covering the present outlets of Lakes Superior and Michigan, these lakes had no connec- tion with each other, nor with the lakes to the east, and their discharge was southward or southwestward into^the Mississippi, from the present heads of these lakes. A small district west of Lake Erie was also occupied by a lake that discharged southwestward to the Wabash. Upon the withdrawal of the ice sheet from the southern peninsula of Michigan and the southern portion of the Lake Huron Basin, the lake at the western end of Lake Erie became expanded and a line of discharge was opened eventually from Saginaw Bay across the southern peninsula of Michigan to the Lake Michi- gan Basin, and this being lower than the outlet to the Wabash, that outlet was abandoned. The waters of the Lake Huron Basin being held at a somewhat higher level than those of the Lake Michigan Basin, the flow of water was from the former to the latter. The glacial lake which discharged across the southern peninsula of Michigan extended over the district between Lake Huron and Lake Erie, as well as the Lake Erie Basin and the low district bordering it on the south and Avest. It apparently did not extend far into the Ontario Basin, as a study of moraines indicates that the ice sheet occupied that basin at the time of this discharge. It thus appears that the Chicago Outlet at one time was the line of discharge for an area much larger than the present Lake Michigan Basin. Three well-defined beaches have been recognized at the southern end of the Lake Michigan Basin above the level of the present beach, which are known a;s the Upper or Grlenwood beach, the Second or Calumet beach, and the Third or Tolleston beach. THE UPPER OR GLENWOOD BEACH. This beach receives its name from the village of Grlenwood, on the Chicago and Eastern Illinois Railroad, a few miles south of the limits of Chicago. The name has been selected (1) because the beach is especially well developed at that village, and (2) because, being near the State line of Indiana and Illinois, the name will be familiar to residents of either State. In the Illinois portion of Lake Chicago this beach is present, except for a few miles between Waukegan and Winnetka, where the lake shore is now fai-ther west than it was at the time this beach was formed. Li Indiana the beach is present throughout the entire extent of the border of THE GLACIAL LAKE CHICAGO. 429 Lake Chicago in that State, being nowhere less than 2 and in places 12 miles back from the shore. In Michigan it is absent for a short distance at the "clay banks," north of New Buffalo, where the present shore stands farther east than the shore of Lake Chicago. It is also absent for the same reason for a few miles near the line of Berrien and Van Bnren counties, north of St. Joseph, Michigan. Tracing in detail the course of this beach is as follows : From the Wisconsin line southward to South Waukegan it stands onh" 1 to 2 miles back from the shore of Lake Michigan and comes out to that shore at the poiut where the bluff of till sets in south of Waukegan. This bluff of till stands above the highest lake level as far south as Winnetka. From Winnetka a cut bank, nearly 20 feet in height, extends south along the face of the east till ridge noted above to its terminus, perhaps 1 mile from the point where the old shore departs from the present shore of the lake. From the terminus of this ridge a bar was built out southwestward 6 or 6 miles, terminating about a mile east of Chicago River, in the west- ern part of T. 41, E.. 13 E. The bar sends out two prominent spurs to the west, a distance of nearly 1 mile. These probably mark the termini in its early stages of growth. The average width of this bar is about one-fourth mile, and it was built up to a height of 10 to 20 feet above the bottom of the bay back of it. It consists largely of gravel, but has a liberal admix- ture of sand. The bay back of this bar extended to the valley of the Chicago River and has a width of 2 to 3 miles. The northern end finds a narrow extension northward in Skokie Marsh. The site of this old bay is now largely luider cultivation, though some portions are still marshy. The question naturally arises whether this accumulation of gravel and sand was formed by the lake currents and waves independent of the Chicago River, or was largely formed as a delta from that stream. This deposit is not in the form of a delta built up at the debouchure of the river into the lake, but lies some distance to the east of the river valley, thus indicating that it was formed by the lake. Moreover, to make it still more evident that it was the lake and not the river which contributed the great bulk of the beach deposit, it is found that the river valley above the jjoint where it entered the old lake has very little assorted material, such as would accu- mulate above a delta. 430 THE ILLINOIS GLACIAL LOBE. The beach appears on the west side of the Chicag-o River, in sec. 19, T. 41, R. 13 H, about a mile northwest from the terminus of the bar. From this ])oint southward to Oak Park the shore is usually a cut bank ranging from 6 to 25 feet in height, with occasional deposits of beach gravel and sand along its front. At Oak Park there is an extension of gravel down the east side of the Des Plaines River similar to that of the bar east of the Chicago River noted above. A ridge or bar 20 to 40 rods in width and 10 feet or more in lieight extends from Oak P.a-k south about 2 miles to the south part of sees. 13 and 14, T. 39, R. 12 E., and there terminates abruptly with a level nearly 20 feet above the plain on its immediate borders. Passing to the west side of the Des Plaines River, the beach ajjpears about a mile above the southern end of the bar just described, and passes in a curving course westward through the south edge of Maywood, in sees. 14, 22, and 16, T. 39, R. 12 E. This portion of the beach is only 2 to 4 feet in height, and at the west it fades out completely. Its faintness in this district is probably due, in part at least, to the protection from wave action occasioned by the bar just described. Upon passing south and crossing Salt Creek, about a mile from the point where the beach fades out, it reappears as a well-defined ridge, composed of sand and gravel, rising from 10 to 12 feet above the border of the plain on the east, and ha^^ing a breadth of 30 to 40 rods. Following- this beach southward, it changes in about a mile to a cut bank, which is well defined from that point southward to the lake outlet, a short distance south of Lagrange. Its course is through the east part of the city of Lagrange, where it is in the form of a cut bank 10 to 15 feet in height. Passing to the west side of the outlet, near Willow Springs, the shore line is found as a cut bank along the east face of the prominent morainic tract which occupies the interval between the two outlets of the lake. Though mainly a cut bank, the beach is represented occasionally bv deposits of gravel and sand. South from the southern or Sag outlet, tlie shore is carved on tlie inner face of the Valparaiso moraine with banks 5 to 20 feet nr more in height, but with only occasional deposits of gravel and sand. U])ou approaching the State line, however, near Glenwood, the shore bears away from tlie mora,ine, and deposits of gravel and sand are built up to a height of 6 t H a M u ■|?ll!lo|l?|?|i0|ii l'|oil|l'; o|o?l»l° ; '"[''I "I ! lol '1^ Ml l?ll?l I If ■■ li'-f" li |ili O * S Se S S c! § o o o o o a 470 THE ILLINOIS GLACIAL LOBE. while the new channel has an estimated rock excavation ranging from 60 to 135 feet in depth and scarcely IJ miles in width. Probably the average depth of rock excavation in the new channel is less than 100 feet. The lower rapids have a length of 11.1 miles, the head being- at Mon- trose Island and the foot a short distance alcove the river bridge at Keokuk. From the foot of the rapids there is a narrow valley leading westward aliout 4 miles to the broad preglacial valley. The total descent in the rapids is 22.17 feet, or very nearly 2 feet to the mile. The rate of descent, as in the upper rapids, is greatest in the lower part, there being a fall of about 4| feet in the lower mile and nearly 8 feet in the lower 2 miles.^ Above tliis part the fall, though not uniform, is less definitely broken into rapids and pools than at the upper rapids. Indeed, there appears to be a rock floor forming the river bed throughout the entire length of the lower rapids. A question of much importance is found in the determination of the date at which the Mississippi entered upon the work of excavating its new channel past the lower rapids. The difficulties attending the solution of this question are great, and have been discussed in a special paper by the writer.^ The main points set forth in that pa23er are outlined below. The deflection being toward the east, the drift filling which caused the displace- ment in all probability took place as a result of the invasion of the Kewatin ice field at the Kansan stage of glaciation. But it is not definitel}^ settled - that the present course across the raj^ids was adopted upon the retirement of the Kewatin ice, since there is a possibility that the displacement was farther to the east. The coincidence of the present course with the western border of the Illinoian di-ift suggests the question whether the river inay not have adopted this course as late as the time of the Illinoian invasion. Attention has already been called to the great erosion of Kansan diift along the Mississippi below the lower rapids which occm-red prior to the valley filling that seems to have accompanied the Illinoian stage of glacia- tion. The pre-IUinoian excavation appears to have been nearly as great as 'The foUowiug data are olitained from Greenleaf's report on Water Power of the Mississiiipi and Tributaries : Tenth Census of United States, 1880, Vol. XVII, p. 60. " In tlie first 4,1?00 feet from the lower lock there is a rise of 4.21 feet, then 2.22 feet in the next 3,600 feet, aud 1.67 feet in tlie suc- ceeding 3,600 feet to tlie middle lock, making the fall iu ordinary low water from a point opposite the middle lock to the foot of the ra])ids 8.1 feet." -The lower rapiils of the Mississippi Elver, by Frank Leverett : .lour. Ueol., Vol. ^■I1. 1899, pp. 1-22. THE MISSISSIPPI VALLEY. 471 the post-Illinoian, and therefore much too g'reat to refer to the work of the Des Moines River. But while there seems clear evidence that the channel across the rapids was begun by the Mississippi before the culmination of the lUinoian invasion, it may not follow that it was occupied by that drainage from the close of the Kansan invasion. The probable efPect of the Kansan invasion would be to throw the stream to the east of the preglacial course. Furthermore, since the ice sheet at that stage extended beyond the line of the Mississippi at the lower rapids, the displaced river would naturally take a course through the lowest available district east of that ice margin. This being done, it may have persisted in that course for some time after the culmination of the Kansan stage of glaciation, and possibly until the Illi- noian invasion crowded it westward to the present line. The amount of excavation preceding the culmination of the Illinoian glaciation, however, favors the view that its selection of the course across the lower rapids was made soon after the retreat of the Kansan ice sheet. The value of the lower rapids as a chronometer for determining the time since the Kansan invasion, as well as the relative dates of the Kansan, Illinoian, lowan, and Wisconsin stages of glaciation were considered in the paper just referred to, and the main difficulties were discussed. One great difficulty lies in the fact that there was not a continuous rock excavation. At both the lowan and the Wisconsin stage some filling occurred, and at the Illinoian stage also it is probable that the filling predominated over the cutting. A further difficulty is found in the fact that the drainage basin of the Mississippi above these rapids has suffered great changes in area since the Kansan stage of glaciation, thus greatly affecting the volume of the stream. The work done at the rapids may be roughly stated as follows: (1) The excavation (independent of filling at the Illinoian, lowan, and Wisconsin stages of glaciation, which was subsequently largely removed) comprises («) the removal of a drift deposit capping the limestone which had an average depth of perhaps 25 feet, a length of 15 miles, and a width of 1^ miles; (p) the removal of limestone to an average depth of nearly 100 feet for a length of at least 12 miles and a width of about 1^ miles. The excavation of limestone is estimated to be nearly one-third of a cubic mile. (2) A filling of undetermined amount, but apparently not less than 30 feet, correlated with the Illinoian stage of glaciation, which is weR shown bv the sections at Warsaw and at Yellow Banks below the lower end of the 472 THE ILLINOIS GLACIAL LOBE. rapids (discussed on a preceding- page), and following this filling a nearly complete removal of it along the rapids. (3) The lowan loess tilling, also of undetermined amount, but probably 15 feet or more, and following this a nearly complete removal along the rapids. (4) The Wisconsin sand filling, which seems to have raised the i-iver bed about 50 feet, followed by a nearly complete removal along the rapids. It would be very difficult to estimate the woi'k involved in filling, even though the depth of filhng in the vicinity of the rapids were known. The filling is simply an index of the excess of the material brought in over the transporting power of the stream. To properl}' estimate the work done in a stage of filling, it would be necessary to compute the amount of material carried through the channel as well as that deposited in it. In the case of the lower rapids, it seems doubtful if such computations can be made. The uncertainties involved in changes of di'ainage area are fully as great as in the work of filling. Some data showing the effect of a chang'e of volume upon the gradient of the river are cited by General Warren. At the time when Lake Agassiz discharged through the Mississippi the sti'eam appears to have opened its channel in the Upper Mississippi to a depth in harmony with the bed of Lake Pepin, ^^•llich is about 60 feet below present low water. The lesser volume of water now passing- down the Mississippi has proved inadequate to remove the detrital dam built at the mouth of the Chippewa River (which is at the lower end of Lake Pepin), and thus the bed has been raised in that ^-icinitv about 50 feet. It is thought by General Warren that a filling is now in progress along the gi'eater part of the Mississippi above Cairo as well as below, and that the rapids are the chief places where a marked cutting is now in progress.^ In view of all these qualifying conditions, it seems hazardous to venture a comparison of the work of the Mississippi at the lower rapids with that of the streams on which estimates have been made, or at least to base definite conclusions iipon such a comparison. lu closing this discussion attention is called to the contours of the bluffs of the channel along the rapids and to tlie rate of fall in the rapids. The contours of the bluffs favor the view that excavation began soon after the ' Bridging of the Mississippi : Anu. Kept. Chief of Engineers, r. S. Army, 1878-79, pp. 912-917. THE MISSISSIPPI VALLEY. 473 Kansan stage of glaciation, and has proceeded veiy slowly down to the present stream level. Except at a few points where the river in rounding- a curve is encroaching on its bluff, the rise is gradual from each bank to the brow of the bluff, so that a large jDart of the slopes may easily be cul- tivated. Although the bluffs are largely a firm limestone, they recede about as much as the bluffs formed in glacial deposits at the upper rapids. Their age, therefore, appears to be several times as great as that of the upper rapids. The work performed in cutting away the rock barrier is many times greater than at the upper rapids. No "chains" rise above the general level, as at those rapids, and the fall has been reduced to a very moderate rate.^ Cutting now proceeds very slowly at these rapids, for the river carries but little sediment except at flood stages, and these extend over but a few weeks of the year. If all the features of the new channel be considered, together with the fact of the occurrence of long stages of interruption from cutting, there seems little to oppose the view that the opening or selection of this course may have been at so remote a date as the Kansan stage of glaciation. RE|:STABLISHED STREAM BELOW THE LOWER RAPIDS. The disturbance of the Mississippi Valley drainage below the lower rapids is mainly restricted to the first 50 miles, between Keokuk, Iowa, and Hannibal, Missom-i, where the western or Kewatin ice field at the Kansan stage of glaciation seems to have covered the valley and extended a few miles beyond it. This portion of the valley was left open at the Illinoian stage of glaciation. There is, however, a bare possibility, as noted above, that the Illinois lobe encroached slightly upon the Mississippi Valley just above St. Louis. The disturbance of drainage was but temporary at either place, and the present river is fully reestablished in the preglacial course, its valley bottoms are as wide as those of the preglacial river and i-ange from 5 to nearly 10 miles in width. The rock bottom of the preglacial val- ley, like that of the section above the rapids, is considerably below the level .of the present stream, as shown by the table presented below. ' It is probable that in the early part of the opening of this new channel the gradient was much steeper than now, and possibly falls of some height existed. But as yet few definite criteria bearing upon this early condition of the valley have been recognized. 474 THE ILLINOIS GLACIAL LOBE. DEFLECTIONS SOUTn OF GLACIAL BOUNDARY. It seems necessary to refer briefly to two slight deflections of the Mis- sissippi, one of which is below the hmits of glaciation and the other near the j)oint where the glacial boundary bears eastward away from the Mississippi Valler. The former is certainly independent of obstruction by the ice, and the latter may be also. The deflection near the glacial boundary is at Fountain Blufl", Jackson County, Illinois, where a rocky point similar to that at Fulton has been cut off' from the west bluff'. The broad preglacial valley, as at Fulton, is still occupied by the stream at flood stages, but is much less direct than the course across the rocky point. In explanation of this peculiar feature it is sug-gested that the encroachments of the Mississippi upon the rocky point had so broken down the crest that a moderate silting up of the valley, which probably occm-red dm-ing- the loess deposition, enabled the stream to cross it. The persistence of the stream in this course is probably attributable to the more direct line of discharg-e. Possibly the presence of the ice in the valley immediately north and east of this rocky point was influential in diverting the stream across it. The deflection farther down the river is at Thebes, Illinois, where for a distance of about 6 miles the river is excavating a new course across a rock point which projects westward into Missouri. An inspection of this district shows that the alti- tude of the rock in the roek;w point crossed by the stream is so low that it is necessary to assume but little silting up of the preglacial channel to have made it possible for the stream to take the present direct coiu'se, probably not more than 50 feet above the present level of the river. A silting of this amount may be supposed to have occurred during the loess deposition. ROCK FLOOR AND PRESENT STREAM COMPARED. In this discussion each of the preglacial valleys utilized by the present Mississippi are included. The data concerning the rock floor are obtained from well borings or from tests for bridges, but are not .sufficiently full to show whether the lowest part of the valley floor has at any point been reached, much less do they indicate the lowest part at all points. It seems probable, however, that the majority are in the deep part, since they are located near the middle of the preglacial channel. They at least indicate approximately the depth of preglacial excavation, and it is thought that thev throw some light upon the slope of the rock bottom. THE MISSISSIPPI VALLEY. 475 In the table which follows it will be observed that the I'ock bottom has a lower altitude at St. Paul, Minnesota, than at several points farther down the present stream, a feature which is thought to sustain the interpretation made by Hershey, that a divide has been crossed between St. Paul and Dubuque. In a paper prepared by the writer a few years ago^ this low altitude at St. Paul and vicinity was suggested to be due either to north- ward differential depression or to a local deepening, such as might have resulted from a waterfall or from subglacial erosion by water or ice. How- ever, no evidence of the operation of these agencies has been discovered, and they could not have been operative within the Driftless Area. These suggestions do not, therefore, seem so pertinent as the interpretation made by Hershey. Altitudes of rock bottom and present Mississippi. Location. Distance, Low "water, above tide. High water, above tide. Roclc floor, above tide. St. Paul, Minn Lake City, Minn Winona, Minn Lacrosse, Wis Prairie du Chien, Wis Dubuque, Iowa Sabula, Iowa Fulton. Ill Leclaire, Iowa (new channel) Rock Island, 111. (new channel) , Muscatine, Iowa (new channel) Near Wilton, Iowa (old channel) Near Muscatine, Iowa (old channel) Mouth of Iowa River Burlington, Iowa Fort Madison, Iowa Mites. 55 40 20 60 55 36 16 20 16 24 Feet. 683 658 639 628 604 585 572 566 562 542 .^>31 Feet. 702 (?) 656 643 623 607 592 587 576 560 547 2 530 18 523 24 511 18 502 547 539 527 518 Feet. a 483 6495 c503 doOi di92 ^453 e429 400± 550 530 506 /400- -7 388 445— 430— 7(365 oN. H. Winohell, Am. Geologist, Aug., 1892. 6 Geol. of Minnesota, Vol. II, p. 17. cData furnished by Dr. TJ. S. G-rant in letter. dChamberlin and Salisbury, Sixth Ann. Kept. TJ. S. Geol. Survey, p. 223 eData given by "W. K. Oake, ex-mayor of Sabula. /A well at this point, reported by Udden, failed to reach rock at elevation 400 feet above tide. g Two wells in the valley below Muscatine, reported by Udden, reached rock at a level about 142 feet below the low water level of the Mississippi. AC. H.Gordon: Geol. of Iowa, Vol. IH, 1893, p. 246. A well one-half mile north of Fort Madison reached a level about 365 feet above tide without entering rock. The channel may, therefore, be deeper than that shown by the Fort Madison wells. ' Jour. Geol., Vol. Ill, 1895, pp. 740-763. 476 THE ILLINOIS GLACIAL LOBE. Altitudes of rock bottom and present Mississippi — Gontiuued. Location. Montclare, Iowa (old channel) Montrose, Iowa (new channel) Keokuk, Iowa (new channel) Qnincy, 111 . (rock shelf) Hannibal, Mo ^ Louisiana, JIo Mouth of Illinois River Bellefontaine, Mo. (on Missouri River) East St. Louis, III East Carondelet, 111. (on rock shelf?) . . Fountain Bluff, 111. (new channel) Near Wolf Lake, 111 Thebes, 111. (new channel) Cairo, 111 , Distance, ^^o^^f^f' jHigh water, above tide. , above tide. Feet. Feet. Kock floor, above tide. 9 12 38 17 25 68 17 24 6 100 15 25 35 500 477 458 450 437 403 402 380 377 313 305 291 270 514 494 476 467 453 422 420 J- 414 412 357 350 339 321 Feet. fl374 490 475 6413 c362 d380— (?) e295 /284 330 300 ^255- 280 (?) a Beck's artesian well, at Montclare ; see Geol. of Iowa, "Vol. Ill, p. 247 ; also this report, fig. 5. b Bridge piers rest on a rock shelf 35 to 40 feet below low water: Eept. P. S. Army Engineers. 1878. cData concerning channel piers furnished by W. S. Liiicoln, chief engineer of Wabash Kailroad. St. Louis, Missouri. d Bed of present stream is 380 feet above tide : Eept. TJ. S. Army Engineers, 1878. e Missouri River Commission, Rept. for 1890. The low-water altitude here given is on the Missouri. /Data concerning depth to rock at bridge piers furnished by Robert Moore, C. E., St. Louis, Missouri. ■ fif A well made by Bolin Sublette failed to reach rock at 50 feet below river level. The fact that the rock bottom in this and other valleys of the Upper Mississippi region lies considerably below the present streams has often been cited in evidence of a great preglacial altitude of the region. This interpretation seems questionable, inasmuch as there appears to be an adequate fall to the seaboard from the rock floors of these ^'al]e}'s, even though the altitude were no greater than at present. In the ■s'alley under consideration the rock floor in the 210 miles between Fort Madison, Iowa, and St. Louis, Missouri, makes a descent of about 80 feet, or 4| inches to the mile, and stands sufliciently high at St. Louis to maintain a similar fall to the Gulf were a direct channel to be opened. A somewhat similar gradient appears also to be maintained in the portion above Fort Madison. Although the gradient is somewhat lower along the rock floor than that of the present Mississippi, it is about as great as that of the present Ohio, which has a fall of but little more than 5 inches to the mile in the 967 miles from Pittsburg to Cairo. MINOK TIUBUTAEIES OF THE MISSISSIPPI. 477 The breadth of the valley excavation seems also to support the view that it was produced under a moderate or low rather than a high stream gradient. It seems improbable that a stream which was cutting down rapidly could have formed a valley several miles in width such as appears along the line of the Mississippi below Muscatine, or along the line of other preglacial valleys occupied by the Mississippi above Clinton. So far as known, the preglacial channels under consideration have furnished no posi- tive evidence of the existence of narrow trenches cut below the general level of their rock bottoms. A few rock shelves have been found extending out a mile or more, as at Quincy and St. Louis, but these occur at points where the river has, in comparatively recent time, been encroaching upon the rock bluffs, and may, therefore, be a more recent product than the deeper part of the valle3^ In the present state of knowledge it certainly seems unsafe to cite them in evidence of a jjreglacial gradation plane standing- above a lower part of the rock bottom. MINOR TRIBUTARIES OF THE MISSISSIPPI. Since the lUinoian invasion encroached only a few miles upon the dis- trict west of the Mississippi (in the southeastern part of Iowa), it has not greatly influened the course of the western tributaries. The larger western tributaries in southeastern Iowa, as above noted, were temporarily deflected southward along a course immediately outside the lUinoian ice border, but these have regained the courses opened prior to the Illinoian invasion. The tributaries here discussed are, therefore, mainly on the eastern side of the Mississippi. The discussion begins in northern Illinois and the streams are taken up in order southward. APPLE KIVER. A few streams lie wholly within the driftless poi-tion of northwestern Illinois and adjacent parts of Wisconsin and may, therefore, be passed by, since they maintain their preglacial courses. It is, however, necessary to mention one stream, Apple River, which lies almost wholl}' within the limits of the Driftless Area, but which has receiA^ed a marked accession of drainag-e because of the blocking of a preglacial tributary of the Pecatonica. This diversion occurs just below the village of Millville, as shown in PI. XII. For about 3 miles below Millville the stream is in a gorge but little wider than its bed. The small preglacial Apple River is then entered. 478 THE ILLINOIS GLACIAL LOBE. PLUM EIVER. Plum River lies partly within the Driftless Area, but its lower course and two important eastern tributaries traverse glaciated districts on the southeast border of the Driftless Area. By reference to the Savanna topographic sheet it will be seen that the stream passes through a gorge in southwestern Woodland Township, Carroll County, which appai-ently was formerly the site of a divide between the Plum River drainage and a much smaller stream entering the Mississippi at Savanna. The course of the preglacial Plum River was probably southward through the glaciated dis- trict, along a line a few miles to the east of its present lower coui-se, but as yet the precise location of the valley has not been ascertained. Caj-roll Creek, one of the principal eastern tributaries of Plum River, apparently discharged southward through Johnson Creek Valley, from a point imme- diately east of Mount Carroll. It now passes westward through a series of gorges in the vicinity of Mount Carroll and enters a small preglacial valley about 2 miles west of that city. The interval between Carroll Creek and Johnson Creek is completely filled with di-ift for a distance of about 4 miles. The di-ift filling terminates abruptly near the point where the Chicago, Burlington and Northern Railway crosses Johnson Creek. From that point southward a preglacial valley fully a mile in width leads down to the Mississippi. No stream of consequence enters the Mississippi on the east between Plum River and Rock River. As the latter stream constitutes one of the major tributaries, its discussion is taken up farther on. We pass, therefore, to the district south of the mouth of Rock River. EDWARDS RIVEE. • Edwards River, a stream which has a length of about 60 miles, leads westward from Henry County through Mercer County, Illinois, entering the Mississippi nearly opposite the mouth of the Iowa River. Its head- Avater portion consists of several streams which converge to form two forks that unite in south-central Henry County. From the junction of these two forks a remarkably direct westwai-d course is taken, so that from points on its bluffs views may be had for sevei'al miles up or down the stream. This portion has only insignificant tributaries and drains a very narrow belt. The directness of its course and the narrowness of its drainag-e basin are MINOR TRIBUTARIES OF THE MISSISSIPPI. 479 due to peculiarities of drift topography, there being in the district through which Edwards River flows a tendency to slight ridging in a general east- west direction, with broad, shallow depressions separating the ridges. Edwards River follows one of these depressions, while Pope Creek, which flows parallel with it on the south, follows a neighboring depression. A depression north of Edwards River differs from that of the two valleys just mentioned in separating its waters, a portion flowing directly west to the Mississippi through Copper Creek and a portion east and north into Rock River through Mill Creek. None of these streams, so far as the writer is aware, reach the bottom of the drift, yet it can not be assumed that they follow preglacial lines, for well sections indicate that the ridges and depres- sions are largely independent of the altitude of the underlying rock surface. HENDERSON RIVER. Henderson River, which drains much of northern Henderson, northern "Warren, and part of Knox counties, Illinois, though having a length of scarcely 50 miles, furnishes a discharge through its numerous branches for an area of fully 500 square miles. The courses of the main branches seem to have no dependence either upon the underlying rock surface or upon drift topography. They traverse a very smooth district having gradual westward descent. The courses of the several streams are proba- bly the result of slight advantages in the inclination of the slopes, at present difficult to discern. These streams have now in several instances cut down into the rock, and their courses seem to be independent of pre- glacial lines. FLINT RIVER. The first western tributary of the Mississippi to claim attention is Flint River, a small stream entering the Mississippi immediately north of Burlington, Iowa. Its source is in the marginal ridge of the Illinoian drift near New London, Iowa. The stream flows thence southeastward to the Mississippi across a gradually descending plain. It appears to disregard the courses of preglacial drainage lines, for in its upper course drift deposits extend in places to a depth of 250 feet, while in its lower course it has carved a channel through the rock ledges, whose cherty layers give to the stream its name. 480 THE ILLINOIS GLACIAL LOBE. LOST CREEK. Lost Creek, a small westeru tributary of the Mississippi draining the eastern portion of Lee County, Iowa, occupies a valley markedly larger than other streams of its size which have cut channels in the Illinoian drift, a feature which appears to be due to an occupancy of the valley by a larger stream than the present one prior to the Illinoian ice invasion. The present head of the stream is in the marginal ridge of Illinoian drift near West Point. It seems not improbable that streams now draining south- ward through Sugar Creek found their outlet through Lost Creek Valley prior to the Illinoian invasion. The interpretation is rendered difficult because of the interruption made by the large stream channel of the tem- porary Mississippi, a channel which, as noted above, governs the present di-ainage of the streams outside the Illinoian drift from Skunk River southward. BEAR CREEK. Two small eastern tributaries of the Mississippi River remain to be considei-ed — Bear Creek and Bay Creek. The former drains the south- western part of Hancock and the northern part of Adams counties, Illinois. It has a widely branching drainage system, and the courses of the several tributaries were probably determined by the slope of the drift plain. One of the tributaries heading near Sutter leads northeastward for a few miles along "Big Meadow Channel," an abandoned valley of a larger stream, but turns away from that valley to form the north fork of Bear Creek. This north fork traverses a region of very thick drift, yet it may have no dependence on the course of preglacial drainage, but the lowei* course of Bear Creek evidently follows a preglacial line. The abandoned valley just mentioned is described below. BAY CREEK. This stream drains much of Pike County, Illinois. Its headwater por- tion leads from the north border of the county southeastward towai'd the Illinois, following a sag between two Illinoian drift ridges and nearly reach- ing the Illinois River, opposite the village of Bedford. It then curves around to the southwest, passes through a gap in the rocky ridge, which to the north and south constitutes the divide between the Mississippi and the BIG MEADOW CHANNEL. 481 Illinois, and enters the Mississippi Valley opposite the town of Louisiana, Missouri. The deflection to the west is due to the ridge of Illinoian drift which follows the east border of the stream and prevents it from entering the Illinois Valley. The gap through the rock divide was apparently broken down below the level of the di'ift-filled districts to the east prior to the ice invasion, and thus offered no obstraction to the westward deflection of the di-ainage. There are several small creeks entering the Mississippi between Bear Creek and Bay Creek, but which scarcely merit special mention, since they usually take a somewhat direct course to the river, following the slope of the drift surface. Those in Adams and northwestern Pike counties are in some casesy deflected slightly by the drift ridges formed on the west border of the Illinoian drift, and find passage to the river through gaps in these ridges. In Pike and portions of Adams counties these creeks in part follow preglacial lines. BIG MEADOW CHANTSTEL. Under this name is discussed a channel which has been excavated in the Illinoian drift by a stream which long since ceased to flow. The chan- nel is distinctly traceable in a course about S. 65° W. from near the town of Bushnell, Illinois, to the valley of the Mississippi in western Hancock County, a distance of 60 miles (see PL VI). Throughout its entire length the valley has bluff-like borders, which range in height from 20 feet to about 50 feet. In width it ranges from one-fourth to fully one-half mile. Its bot- tom is underlain by sandy and gravelly material, apparently alluvial, and there seems little question that it has been occupied and formed by a stream of considerable volume. From near Bushnell the valley is now followed westward across McDonough County by East Crooked Creek. From the mouth of this stream the channel continues along Middle Creek (reversed) to the present divide between the Illinois and Mississippi drainage systems. In its passage across this divide it has cut a valley fully 40 feet in depth and more than half a mile in width. It is this portion which has long been known by the residents as the "Big Meadow." At the west it continues down Big Meadow Creek to another headwater tributary of Bear Creek, and thence follows the course of that creek (reversed) to the divide between Bear Creek >I0N XXXVIII 31 482 THE ILLINOIS (iLAOIAL LOBE. and the Mississippi near Sutter. The valley is here well defined and nearly as deep as at the "Big- Meadow divide." From Sutter it leads down the valley of a small stream known as Rock Run, passing throug-h a gap in the marginal ridge of lUinoian drift just before entering the Mississippi Valley. Tlu-oughout this entire distance of not less than 50 miles its course is remarkably direct. The precise variations in the elevation of its bottom have not been determined. The eastern end near Bushnell, the "Big Meadow divide," and the divide at Sutter, all stand very nearly 650 feet above tide. With the exception of the descent into the Mississippi Valley west from Sutter, the slope of the valley bottom probably nowhere exceeds 5 feet to the mile, and is usually scarcely half that amount. This singular valley appears to find its parallel in the valleys accom- panying some of the eskers, an instance of which in Kane County has already been discussed (p. 284). No esker, however, lies in the "Big Meadow" Valley. It seems probable that the stream which excavated this channel was confined beneath the ice sheet, and thus held to a direct course across the low divides and shallow depressions covered by the ice. The hypothesis of a piracy of the stream which formed this channel by the two creeks which now drain it, Crooked Creek and Bear Creek, has been con- sidered and seems untenable. The valley was evidently formed by a stream lia\ang much larger volume than either of these creeks possesses at the points where they depart from this old channel. Furthermore, the course of the channel is such as can scarcely be supposed to have been inaugurated without the confining influence of the ice sheet, for the present courses of drainage are determined by the general slopes of the region and are the natural lines of discharge. It seems, necessary, therefore, to refer this abnormal drainage to a subglacial stream. In this connection it may be remarked that the s}^steni of parallel streams in McDonough County, all bearing west-southwest, may have been a result of slight channel development by subglacial streams along these lines. Similarly the depressions occupied by Edwards River, Pope Creek, and Copper Creek, in Mercer and Rock Island counties, may have been at first avenues of discharge for subglacial waters. There seems, however, in this latter district to have been a more decided development of ridges, parallel with the dejjressions, than is found in the vicinity of the "Big Meadow" channel. INFLUENCE OF THE DEIFT UPOIS^ DRAINAGE. 483 TtOCK RIVER DRAINAGE BASIN. Rock River, which drains much of northwestern Illinois, has a length of nearly 300 miles and a drainage area of about 11,000 square miles. Nearly half its length and more than half its di-ainage area are in Wisconsin. Its general course is southwest from southern Wisconsin across northwestern Illinois. From its source to Janesville, Wisconsin, it traverses a region covered by drift of Wisconsin age, and its basin is characterized by extensive swamps and numerous small lakes. The drainage appears to be largely independent of preglacial lines. Just above Janesville the river crosses the outer or "Kettle" moraine of the Green Bay lobe, and soon enters a broad preglacial valley filled with a gravel deposit which heads in that moraine. The bordering uplands are covered by drift of lowan age, as well as by earlier glacial deposits of Illinoian and possibly of still greater age. Below Janesville, with the exception of a few miles near its mouth in Rock Island County, Illinois, the present stream lies within the limits of the lowan drift. The western boi'der of that drift, however, extends but a few miles west of the stream at any point, and for a few miles below Rockford follows nearly the course of the river. The portion of this drainage basin lying outside the Wisconsin drift is generally undulating and well drained, but extensive swamps occur along Green River, an eastern tributary. The western tributaries lie mainly outside the limits of the lowan, and the chief tribu- tary, Pecatonica River, drains a small part of the Driftless Area. The preglacial valley entered by Rock River near Janesville, Wiscon- sin, is followed southward a distance of 50 miles to the mouth of Kishwau- kee River, a few miles below Rockford, Illinois. The river and valley there part company, the valley continuing southward and apparently con- necting with the Illinois at Hennepin, the river turning- southwestward to enter the Mississippi (see PL XII). In this southwestward course is found a series of small valleys separated by low divides which afforded the stream a means of escape without producing a great amount of rock excavation, as will appear from the detailed description given below. THE PREGLACIAL DRAINAGE. The preglacial valley entered by Rock River near Janesville may be traced without difficulty as far south as Rochelle, in southeastern Ogle 484 THE ILLINOIS GLACIAL LOBE. County, where a bulky moraine wliicli forms the west border of the Wis- consin drift makes further tracing difficult. The valley has been so incom- pletely filled outside the limits of the Wisconsin di-ift that its rock bluffs rise perceptibly above the general level of the filling along the valley. But within the limits of the Wisconsin drift the valley has not only been com- pletely filled but the general level of the drift surface rises 100 feet or more above its bluffs. Its course can be known, therefore, only through data obtained by deep borings. These indicate that it leads southwestward across eastern Lee and northeastern Bureau counties to Princeton, and thence southward to the bend of the Illinois River at Hennepin. The breadth of the valley, in the portion exposed to view, averages about 3 miles, though it in places reaches nearly 5 miles. Its rock bottom appears to be somewhat lower than that of the preglacial valley occupied by the neighboring portion of the Mississippi. Chamberlin reports a boring at Lake Koshkonong, Wisconsin, which failed to reach rock at an elevation only 450 feet above tide. The rock was reached on the Missis- sippi in the same latitude at about 490 feet. Borings at Princeton, Peiai, Bureau Junction, and Putnam, Illinois, enter rock at about 340 feet above tide, while borings on the Mississippi at Fort Madison, Iowa, which is some- what farther south, reach rock at about 365 feet, though one boring failed to reach the rock at that elevation. No borings have been made between Lake Koshkonong and Princeton which are calculated to test the depth of the preglacial valley. Borings at Janes-^lle, Wisconsin, and Rockford, Illinois, made at the foot of the west bluff, enter rock at about 530 feet above tide. They can scarcely be supposed to represent the deptli along the middle of the valley opposite these cities. Several wells have been smik in eastern and southern Lee County and in northeastern Bureau County, Illinois, which fail to enter rock, though they terminate at an eleva- tion less than 500 feet above tide. From the data at hand it appears that the rock bottom descends from 450 feet or less above tide in southern Wisconsin to 340 feet above tide at the bend of the Illinois, 90 to 100 miles farther south. Several of the large preglacial tributaries of the old valley may be traced readily in tlie district lying outside the limits of the Wisconsin drift. The Pecatonica River, which is the largest of the present tributaries, is EOCK EIVEE DEAINAGE BASIN. 485 reestablished along the preglacial line, though the lower half of its course lies within the limits of the glacial district. The headwater portion of one of the western tributaries of the Pecatonica — Yellow Creek — has been diverted into Apple River, a tributar}^ of the Mississippi. This stream also makes slight deflections into the bordering bluifs in its lower course. Sugar River, the principal northern tributary of the Pecatonica, occupies its pre- glacial line, except, perhaps, at the headwaters. Many of the smaller trib- utaries are also largely in preg'lacial lines. Leaf River, which now drains a portion of northern Ogle County eastward into Rock River, is following a preglacial line which continued eastward across the present course of Rock River, through an abandoned channel known as "Stilhnan Valley," to the village of Stillman Valley, and thence northeastward to the old Rock River Valley in southern Winnebago County. Rock River follows the line of this preglacial valley for a few miles in the vicinity of Byron, but in the reverse direction from the stream which excavated the valley. Rock River also makes use of small tribu- taries of the preglacial Leaf River. From the mouth of the present Leaf River it passes up the valley of a small southern tributary for a few miles. Before entering the old Leaf River Valley east of Byron it has utilized a small northern tributary of that valley. Bluff Creek also, which enters the present Rock River a few miles above Byron, has a preglacial course southeastward across the present Rock River to a lower course of the ]3re- glaciai Leaf River. The Kishwaukee River, the first important eastern tributary of Rock River south of the Wisconsin line, is in a new course for a few miles below the junction of the north and south branches. It is not clear whether the old mouth was a short distance north of the present mouth or whether the stream passed southward up the south branch to the vicinity of Fielding and thence across to the old Rock River Valley near Esmond. The north and south branches each occupy a preglacial valley for a few miles above their junction, but the headwater portions of each stream are in new val- leys. The head of the north fork may not have been so far east as now, for the effect of the ice sheet generally in northern Illinois has been to force streams into the Rock-Illinois drainage basin from the east slope of the limestone ridge which separated this basin from the Lake Michigan Basin. 486 THE ILLINOIS GLACIAL LOBE. Kite River, which now flows northwestward into Rock River at Ore- gon, Illinois, occupies a preglacial western tributary of the old Rock River which may be traced southeastward into the old valley at a point south of Rochelle. The head of the preglacial stream appears to have been in the hills back of the town of Oregon. The present Rock River therefore cuts off only the headwater portion of this preglacial valley. The preglacial drainag-e of southern Ogle, northern Lee, and eastern Whiteside counties appears to have been directly toward the preglacial Rock River in southern Lee and northern Bureau counties. The jjresent Rock River intersects several of these streams midway of their course and diverts them westward into the Mississippi. The lower courses of these preglacial streams are now concealed beneath the sand deposits of the Green River Basin. Probably western Whiteside and neighboi'ing portions of Henry and Rock Island counties, now tributary to Rock River, were tributary to a jireglacial stream which connected directly with the Mississippi, if they did not themselves discharge directly into the stream. PRESENT COURSE OF ROCK RIVER. At the mouth of the Kishwaukee River, 7 miles south of Rockford, Rock River turns directly away from the broad preg'lacial valley and for 50 miles takes its course southwestward through a much narrower A-allev (see PI. XII). The narrow valley extends to western Lee County, a few miles below the city of Dixon. From this point to the Mississippi, a dis- tance of about 80 miles, the river flows in the broad lowland known as the Green River Basin. A few miles above its mouth, however, the basin is inteiTupted by island-like strips of upland, around which the stream takes its course, as .shown in PI. XVIII. Its main channel is south of the islands, the other channels being occupied only by sloughs and sandy plains. A somewhat detailed study of the nari-ow portion of the -valley has been made with a view to determining the amount of rock excavation accom- plished. This study has brought to light an interesting series of changes in drainage, some of Avhicli have already been mentioned. This narrow poi'tion is naturally divided into the following sections, taken in order, beginning at the point of deflection from the preglacial valley and passing ROCK EIVER DRAINAGE BASIN. 481 soutliwestward. The length of each section and estimated amount of rock excavation are also given : Table showing rock excavation in the new course of Rock River. Distance. Excavation. Miles. Mile-feet. 1 15 3 100 1 30 3 60 7 50 3 60 2 75 7 125 2 40 20 500 (1) Across a rock ridge (2) Up preglacial Bluff Creek (3) Across a rock divide (4) Down nortli tributary of preglacial Leaf River... (5) Up preglacial Leaf Kiver Valley (6) Up a south tributary of preglacial Leaf Kiver (7) Across a rock divide (8) Across Kite River Valley and associated lowlands (9) Across a rock divide (10) Dowu a preglacial valley to Green River Basin.. Total 49 1,055 Throughout this narrow portion the stream maintains a width of about 500 feet, but its valley ranges in width from 1,000 feet to fully a mile. The stream makes a descent of only 60 feet, being 680 feet at the mouth of Kishwaukee River and 620 feet at the head of the Sterling rapids, where it opens into the Green River Basin.^ So far as known, it has no rock rapids in this portion of its course, and there are places where its bed lies 20 feet or more below the low-water level of the stream. The occurrence of these deep places along the river bed and the data obtained from wells along the valley indicate that the rock bottom may generally lie not less than 20 feet lower than the present stream. It has seemed necessary, therefore, in ' estimating the amount of rock excavation, to assume that it extended to this depth. It may have extended even deeper. Taking up now the several parts of this nan-ow section of the river, the following are the data upon which the estimates of the rock excavation accomplished in it have been made : In the passage across the rock ridge between the preglacial Rock River and Bluff Creek the stream has cut for one-fourth mile at the crest of the ridge to a depth of fully 70 feet and a width of about 1,000 feet, and presents the cross section shown in fig. 6, No. 2, but on the slopes of the ' Computed from Greenleaf's Report in Tenth Census, Vol. XVII, 1880. 488 THE ILLINOIS GLACIAL LOBE. N9 I. PREGLAGIflL AND PRESENT VALLEY OF ROCK RIVER AT HOCKFORD, ILLINOIS. N°2-PR0FILE AT COL CROSS9D BYROCKRIVEH AT A' PLATE XI I N93.R0CK RIVER IN PREGLACIAL BLUFF CREEK VALLEY rido-es the rock surface descends to only 20 or 25 feet above the river. The excavation in this ridge is, therefore, not more than 15 mile-feet.^ In the three miles along the preglacial Bluff Creek the amount of cut- ting ranges in depth from 25 to nearly 100 feet and in width from 1,500 to 2,000 feet. The level at which the pre- glacial stream had cut is marked by a change in the angle of slope (see fig. 6, No. 3), that below being* much steeper than that above the preglacial level. It seems safe to assume 100 mile-feet of excavation. On the di^^de between Bluff Creek and the north tributary of the preglacial Leaf River the cutting is estimated to be double that at the neighboring rock divide on the east, or 30 mile-feet (see fig. 6, No. 4). It has a depth of 80 to 110 feet and a width of 1,200 to 2,000 feet. Along the north tributary of the preglacial Leaf River the excavation de- creases from about 80 feet practically to zero. The width of excavation is about 2,000 feet, widening to nearly 2,500 feet at the border of the old Leaf River Val- ley. The excavation is estimated to be 60 mile-feet. In the 7 miles along the preglacial Leaf River Valley the excavation is con- fined to a slight cutting of perhaps 25 feet at the borders of the preglacial xnl- ley, which diminishes to zero before reaching the middle of tJie valley. The valley here is a mile wide, with gi-adual rise to either bluff, as shown in fig. 6, No. 5. The excavation is estimated to be but 50 mile-feet, which is proportionately less than along any other part of this narrow portion of the valley. N94. PROFILE AT COL CROSSED BY ROCK RIVER flT"B'P'-*'''^>'ll NO5.R0CK RIVER IN THE PREGLACIAL LEAF RIVER VALLEY AT BYRON, ILLINOIS. N96 PROFILE AT COL CROSSED BV ROCK RIVER AT t: PLATE XII N''? ROCKRIVEfl INTHEPREOLACIAL KITE RIVER VALLEY ATOREGON.ILL NOaPROFILEAT COLCDCROSSED BY ROCK RIVER AT''d PLATE XI I Fio. 6. — Sctitions ; ro88 Kock Kiver Valley, Id unrtberu lUiTuns. ' A inile-foot embraces a block 1 mile square and 1 foot thick. EOCK RIVEE DEAINAGE BASIN. 489 Aloug the south tributary of Leaf River the Umit.s of preglacial exca- vation are clearly marked as on Bluff Creek. The excavation on Rock River increases from 25 feet or less to about 75 feet. The width of this portion of the valley is about 2,000 feet. The excavation is estimated to be 60 mile-feet. On the divide between the preglacial Leaf and Kite rivers the excava- tion appears to have ranged from 60 feet up to perhaps 125 feet in depth, and the width is somewhat uniformly about 2,000 feet (see fig. 6, No. 6). The excavation is estimated to be 75 mile-feet. In the Kite River Valley and associated lowlands the excavation appar- ently ranged from zero to about 50 feet in deptli. In Kite River Valley the width is a mile or more, but below the valley it is about 2,000 feet. An average cross section is shown in fig. 6, No. 7, which is at Oregon. The excavation is estimated to be 125 mile-feet. South of Kite River the depth of excavation appears to scarcely exceed 50 feet, and no sharply defined col could be found, for, being in the St. Peter sandstone area, the uplands are very uneven. The width of excavation is 2,000 to 2,500 feet, and the total excavation is estimated to be only 40 mile-feet. The profile shown in fig. 6, No. 8, is found at D, PI. XII, and may perhaps cross at the site of an old col. The depth of excavation along the portion of Rock River between the place shown in this profile and the Green River Basin has not been so carefully computed as in the portions above. The river appears to follow the line of a small preglacial stream as far as the mouth of Pine Creek, whose valley has been somewhat broadened by it. Below the mouth of Pine Creek the preglacial valley has been widened but little. The average width of the valley is about one-fourth mile, and in places it reaches nearly a mile. Such is the case at the sharp bend at Grand de Tour and at bends near Dixon. The rock excavation may possibly amount to 500 mile-feet in this lower 20 miles, but it seems as probable that it does not exceed 400 mile-feet, and it may be even less. Combining the above estimates, it appears that there has been not more than 1,055 mile-feet of excavation in the 49 miles of this narrow section of the Rock River Valley, and possibly it falls below 1,000 mile-feet. It may, therefore, be roughly placed at one-fifth of a cubic mile. The present discharge through this valley, based upon estimates by Greenleaf and by Rae, is somewhat more than 4,000 cubic feet per second, that being 490 THE ILLINOIS GLACIAL LOBE. the estimated average yearly flow past the city of Rockford.^ It is not known whether the present flow diff'ers widely from that of the stream which produced this rock excavation, for the excavation appears to have been practically completed prior to the Wisconsin stage of glaciation. The drainage area and the rate of discharge may have been altered somewhat as a result of the Wisconsin invasion. Also a part of the rock cutting may have been produced by a glacial stream at the time of deflection. It is thought, however, that the glacial stream would have expended its energies at the rock divides, and that changes in drainage area are of minor conse • quence, so that the excavation may be assumed to have been chiefly accom- plished by a stream similar in size to the present Rock River. This narrow section of the Rock River Valley carries dejDOsits of glacial gravel which appear to be the continuation of the broad gravel plain that leads down the preglacial Rock River Valley from the Kettle moraine of the Green Bay lobe. This gravel plain stands about 50 feet above the present level of Rock River at Rockford and southward from that city to the point where the preglacial and present valleys of Rock River part company. It has no continuation southward along the preg'lacial valley, but passes instead down the narrow valley of the present stream. Its altitude at Byron, as shown by the railway survey, is 50 to 55 feet above the low-water level of the stream at that point. At Oregon its ele- vation is about 40 feet, and it maintains an elevation of nearly 40 feet from there to the point where it emerges into the Green River Basin above Ster- ling. This filling apparently began a few feet below the present river level, since the wells made along the flood plain encounter gravel to a depth of 10 to 20 feet or more below the stream. However, in places on the borders of the valley it rests upon rock at a level slightly above the present stream. It may not, therefore, amount to more than would be necessary to build the valley up from its present level to a height of 50 feet. Assum- ing this to be the case, the filling will equal about four-fifths of the amount of rock removed from the channel prior to its deposition, or to about 0.16 of a cubic mile. The amount deposited in the 50 miles embraced in the section of tlie pi-eglacial valley between the Kettle moi'aine and the head of this narrow section is much greater. It is at least 50 feet and may amount to 75 feet in deiitli. The widtli being 2\ miles or more, it follows that ■ Seveiiteeutli Ann. Kejjt. U. S. Geol. Survey, Part II, 189(5, p)). 733, 734. BOOK RIVER DRAINAGE BASIN. 491 there was not less than a cubic mile deposited in this section of the ])re- glacial valley, and the amount may possibly approach 2 cubic miles. The amoimt of excavation accomplished since the deposition of the gravel is remarkably small. The valley formed subsequent to this gravel deposition varies but little in breadth in the 100 miles from the Kettle moraine to the lower end of the narrow section. It is usually about 1,500 feet in width, and seldom exceeds 2,500 feet. Its ilood plain is 30 to 40 feet below the level of the gravel plain and its stream bed about 50 feet. The stream occupies about one-third the width of this postglacial valley. The amount of excavation accomplished in the narrow section under discus- sion is estimated to be about 650 mile-feet, or slightly more than half the amount of rock excavation accomplished prior to the deposition of the Wisconsin gravel. It is a matter of much interest to ascertain the relative lengths of time involved in the interglacial rock excavation and the postglacial gravel excavation. This, however, must be left to more refined methods than are now at command. It seems safe to assert that the time involved in the rock excavation was longer than that involved in the gravel excavation, though it must be borne in mind that water may find passage through or over gravel without disturbing it, where it might be cutting rapidly in the soft St. Peters sandstone which forms a portion of the new channel of Rock River. But the greater part of the rock excavation has been in limestone, which would perhaps offer fully as much resistance to erosion as the gravel deposits which now line the valley. The deflection of Rock River into this new course certainly preceded •the Wisconsin stage of glaciation, and probably preceded the lowan. The completeness of the removal of rock barriers along its new course and the general character of the channeling seem to ally it with certain rock gorges found in portions of northwestern Illinois and southern Wisconshi, west of Rock River, which, as determined by Hershey, were largely excavated prior to the lowan stage of glaciation.^ These gorges are discussed below and their relation to the lowan deposits are set forth. Furthermore, the work accomplished elsewhere between the lowan and Wisconsin stages of glaciation throws doubt upon the view that this channel was entirely excavated after the lowan stage of glaciation. The work involved in the ' Pleistocene rock gorges of northwestern Illinois, bv Oscar H. Hershey : Am. Geologist, Vol. XII, 1893, pp. 314-323. 492 THE ILLINOIS GLACIAL LOBE. channeling, therefore, seems referable mainly to the interval preceding the lowan glaciatiou, and only in small part to that succeeding it. An instance of a rock gorge formed subsequent to the lowan stage of glaciatiou is found in the west part of the city of Rockford, where Kent Creek enters Rock River over a series of cascades. The stage of excavation here is far less mature than in the rock gorges which were opened between the Illinoian and lowan stages or in the new course of the Rock River under discussion. Concerning the lower portion of the new course of Rock River, between the city of Sterling and the mouth of the stream, a few words seem necessary. The river enters the sandy plain known as the Green River Basin near the city of Sterling, a j^lain which stands Ijut 25 to 40 feet above the stream. In the 80 miles from Sterling to its mouth the river makes a descent of 84 feet, of which 15 feet occur in passing the rapids at that city, and about 25 feet more in the 18 miles between Sterling and Lyndon. The average descent, including the rapids, is about 1 foot to the mile, or nearly the same x-ate as in the narrow portion of its course in the 50 miles above Sterling. This lower portion of the stream is evidently independent of preglacial lines, for it fre- quently encounters rock ledges, and its bed is entirely floored with rock for several miles in the vicinity of its mouth. The Green River Basin has appar- ently been deeply filled with drift, so that the stream encounters rock only in its passage across preglacial interfluvial tracts. It seems probable that the preglacial channels in this basin reach a level 100 feet or more below the interfluvial tracts, or sufficiently low to correspond with the rock bottom of the preglacial Rock and Mississippi rivers in neighboring districts. Mvich of the erosion accomplished by Rock River in the Green River Basin has occurred since the Wisconsin stage of glaciatiou, for a large part of the surface gravel and sand in which the stream has its channel appears to be an outwash from a moraine of Wisconsin age at the head of the basin. The size of the valley, moreover, corresponds to that of the post- Wisconsin Valley in the upper portion of the stream. The rapids at Sterling also ally it with gorges opened since the lowan, and are consistent with a post- Wisconsin age. GREEN RIVER. • The headwaters of this eastern tributary of Rock River are found in the elevated moraine forming the border of the Wisconsin drift in south- eastern Lee County, Illinois, and standing 1)50 to 1,000 feet above tide. EOCK GORGES OF NORTHWESTERN ILLINOIS. 493 The several headwater streams descend rapidly to the sandy plain outside the moraine. They there soon enter a wet prairie — "Inlet Swamp" — whose altitude is about 775 feet above tide and which covers perhaps 16 square miles. No channel is maintained across this prairie, but from the west end of the pi-airie a stream with a well-defined channel leads westward about 15 miles to another wet prairie — "Winnebago Swamp" — making a descent of nearly 100 feet. In this second wet prairie, which is fully 10 miles in length, the stream has only a poorly -defined channel, but apparently makes a descent of several feet. The western part of the prairie is estimated by Rolfe to stand only 660 feet above tide. In the next 25 miles, to the cross- ing of the Bureau-Henry county line, the stream has a poorly-defined channel, meandering about tlii'ough a series of marshes among sand hills, but making a descent of 60 feet (Rolfe). lu the remaining 35 or 40 miles to its mouth the stream falls about 40 feet and maintains a well-defined channel. In the lower 18 or 20 miles (below Geneseo) it has excavated a valley fully 20 feet in average depth and nearly one-half mile in width. In this section of its course it is bordered by uplands which are far less sandy than the lowland plain known as the Green River Basin. The sand which covers the Green River Basin, as previously indicated, appears to be largely an outwash from the Wisconsin moraine. The chan- nel of Green River is, therefore, of post- Wisconsin age, although traversing a district which stood outside the limits of the ice sheet at the Wisconsin stage of glaciation. The trench which it has cut below Geneseo is entirely in dej)Osits of silt which are also of apparently Wisconsin age. They have an elevation corresponding closely to that of the Wisconsin terrace on neighboring portions of the Mississippi, and it is thought that they are slack-water deposits connected with the swollen Mississippi during the time in which it was building up the terrace. ROCK GORGES OF ISTORTHWESTERIS^ ILLINOIS. In the portion of northwestern Illinois lying between Rock River and the border of the Driftless Area the drift is generally so thin that the streams follow in large part the preglacial lines. There are, however, several instances of the deflection of streams into the edge of the bluff" or across a projecting point on the border of a valley. Such deflections usually occur where a cluster of knolls or ridges of drift greatly obstruct the valley, and they are usually only of sufficient length to pass the obstruction. In some 494 THE ILLINOIS GLACIAL LOBE. cases, however, the stream is thrown across the divide into another pregla- cial valley. The streams in cutting new courses through the rock ledges have found the material so resistant that very narrow channels have been formed which, because of their narrowness and the precipitous rock cliffs on their borders, are known as rock gorges. Several of these rock gorges in Stephenson County have been examined with considerable care and dis- cussed by Hershey.^ His paper contains the following table of measui-e- ments and estimates of a few of these gorges. There is added a more recent measurement of a gorge on Carroll Creek just west of Mount Carroll: Measurements of rock gorges in northwestern Illinois, by Oscar JS. Hershey. No. Situation. Drainage area. Length. Breadth. Depth. Cubic con- tents. Width of bot- tom. Width of present stream. Feet. Ratio ■width of bottom to Tridth of stream. Sq. miles. Feet. Feet. Feet. Cu. yds. Feet. 1 1 mile north, of Freeport. i 950 140 29 140, 000 50 5 10 : 1 2 5 miles northwest of Free- port. 4 850 240 44 330, 000 175 25 7 : 1 3 3 miles south of Freeport. 10 2,050 235 36 640, 000 200 20 10 : 1 4 5 Cedarville ............. 29 1^ 3, 250 225 160 175 57 15 1, 100, 000 21, 875 133 150 25 5 5.3 :1 30 : 1 Cedarville 6 3 miles west of Freeport. 1 950 100 25 88, 000 80 8 10 : 1 7 4 miles west of Freeport. 5 1,100 165 30 202, 000 145 10 14. 5 : 1 8 Carroll Creek 45 2 miles. 180+ 50 3, 530, 000 180 30 6 : 1 From the above table it appears that the gorg-es show remarkable variations in size, the causes for which are not made clear. The small ratio of width of bottom to width of stream displayed by the two streams hav- ing the largest drainage area raises the suspicion that the smaller streams may have had softer material to work upon and thus have been able to accomplish a greater amount of excavation than that displayed b)' tlie two larger streams. The writer has had opportunity to examine onlj- two of the gorges. No. 1 and No. 8 of the above table. These gorges are of some- what different type. The gorge No. 1, on the small stream north of Free- port, has bluffs so broken down that an ascent may easily be made at almost any j)oint. As shown in the table, the top of the gorge has a breadth nearly three times as great as at the bottom, though the gorge is scarcel}' 30 feet ' Pleistocene rock gorges of northwestern lUinnis, by Oscar 11. Her,' it In jiii..^sil t.s ^- Mth^.^hlUhs^ihWi mmMhTi'MiIiP"^ 5 jiiisiils^riiispstsliisiisii^.JssiissH.s siiJ|Jii> •/] x ^ »— < -^ H :^ d M ^M n CS — 1 CO ^^ *** S) tu g ' ^ Q a u E ^ ■P 'or fe •r < kS AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS. 545 the average thickness for each township is 77.9 feet. In making- the esti- mates care has been taken to avoid dupUcations ; thus where several borings have been made on a single square mile which differ very little in distance to rock they are considered as one boring. If, however, borings in close proximity show a wide difference, they are each included in the computation. After avei'aging the drift by townships the question was considered whether the townships in which rock has been struck fairly represent the thickness of the drift. This involved the consideration of their distribution in reference to moraines and in reference to preglacial valleys, both being- lines where the drift has exceptional thickness. It was found that the moraines have been about as thoroughly tested as the tracts of thinner drift separating them, but an examination into the distribution along preglacial valleys has led to the conclusion that they are not adequately represented. Of the 1,179 borings which reach rock, 1,065, or fully 90 per cent, enter it near the level of the preglacial uplands, while only 114, or scarcely 10 per cent, pass markedly below the general level of those uplands before striking rock. It is difficult to decide upon the portion of the surface to be included in the valleys, especially if their intricate network of tributaries is included, but it may confidently be placed at not less than 30 per cent; possibly it may reach 50 per cent. Upon computation it is found that the average depth to rock of the borings along preglacial valleys is 172.44 feet, while the depth of those on the uplands is 67.87 feet. If the uplands comprise 70 per cent of the glaciated portion of Illinois and the preglacial valleys 30 per cent, the average thickness of drift will be 99.23 feet. If the uplands comprise 60 per cent and the valleys 40 per cent, the average will be 109.7 feet. If the uplands comprise only 50 per cent and the valleys 50 per cent, the average will be 120.15 feet. By this method of computation, therefore, the thickness appears to be not less than 99 feet, and it may be 120 feet or even more. The thickness is on the whole greater within the area covered by the Wisconsin drift than in other portions of the State. Of the 487 borings within that area which reach rock, the average drift thickness is 121 feet. Of these borings only 52, or about 10 per cent, have struck preglacial val- leys. The borings on the preglacial uplands enter rock at an average depth of 109.7 feet, while those along preglacial valleys average 221 feet to the MON xxxvui 35 546 THE ILLINOIS GLACIAL LOBE. rock. Of the 18,000 square miles covered by the Wisconsin drift, there are about 4,000 square miles in which the thickness is much below the average. This comparatively thin drift is found in five counties which border the Kankakee River and the Chicago Outlet, viz, Kankakee, Cook, Will, Grundy, and Lasalle counties. There are 254 borings in these counties which enter rock at an average depth of only 68.8 feet. Of these 243 are on preglacial uplands and enter rock at an average depth of only 63.8 feet, while 11 along preglacial valleys average 179 feet to rock. If now the Wisconsin drift area be corrected for the imperfect repre- sentation of preglacial valleys, in accordance with the corrections applied to the whole State, it is found that the average thickness, on a basis of 30 per cent being in valleys, would be 143 feet; on a basis of 40 per cent in valleys the average will be 154 feet, and on a basis of 50 per cent in valleys it will be 165 feet. The general average of the Wisconsin drift is thus 40 to 45 feet above that for the entire State. Turning to the lowan di-ift, there is found a markedly greater amount of drift in the counties lying east of Rock River than in those west of that stream. The few borings which have been made indicate that the thickness in the former district will average not less than 100 feet, while in the latter it is but 50 to 75 feet. The thinness of the lowan drift near its margin is perhaps due in the main to the withdrawal of the loess which apparently has been derived in large part from the lowan ice sheet, but has been scattered widely outside the limits of the lowan till. In the portion of the State lying outside the limits both of the lowan and the Wisconsin till sheets — i. e., the portion occupied by Illinoian till and loess — there is a marked variation in the thickness of the drift. The thinnest drift of the State is found in the district lying east of the Kaskaskia, a district having an area of nearly 11,000 square miles. Of the 138 borings reported which reach rock in that district, 128 are found on preglacial uplands, and enter rock at an average depth of only 20.4 feet. The 10 borings entering rock along preglacial valleys show an average drift thick- ness of 106 feet. In the remainder of the Illinoian drift area the boring-s enter rock at an average depth of about 55 feet, including 52 valley boxings. The average thickness on the preglacial uplands of that region scarcely exceeds 40 feet. AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS. 547 The following- tabular statement sets, forth the proportion of reported borings between each 100 feet within the entire district covered by the Illi- nois lobe, and includes both those which reach rock and those which do not. Knmber. With 400 feet or more 4 With 300 to 400 feet 18 With 200 to 300 feet 138 With 100 to 200 feet 698 With less than 100 feet 2,251 Total 3,109 After the estimates just recorded were completed, the thickness of drift in Illinois was computed on the basis of the requirements of the topography, the data obtained by Chamberlin and Salisbury in the Driftless Area ser^ang as a guide. The investigations in the Driftless Area led to the opinion that 150 to 200 feet of drift is necessary to fill the valleys up to the level of the divides, all the summits of the ridges being still left bare, while 300 feet would be necessary to bury the region as deeply as in the heavy drift regions of the four adjoining States.^ Upon turning to Illinois, it is found that the drift in places has filled the valleys completely and brought the surface up to a level perhaps 100 feet or more above the summits of the ridges. In much more extensive districts it has barely filled the valleys, while in fully half the State it has fallen short of filling the valleys, the amount in the different localities being two- thirds, one-half, one-third, or one-fourth as great as is necessary to com- pletely fill the valleys. It is estimated that there may be about 4,160 square miles along the bulky moraines of the Wisconsin drift in which the average thickness reaches 300 feet; but in the greater part of the Wisconsin drift area it can scarcely exceed 200 feet, for the filling extends but little above the level of the rock divides. There is estimated to be 10,975 square miles in which the average thickness may reach 200 feet, this district lies mainly within the Wisconsin drift but extends beyond this drift down the Illinois Valley through Mason and the adjoining portion of Logan County into Cass County. The area of lowan di'ift in eastern Winnebago, Boone, and neigh- boring portions of McHenry and Kane counties may possibly have 150 1 Sixth Ann. Rept. U. S. Geol. Survey, pp. 257-258. 548 THE ILLINOIS GLACIAL LOBE, feet of drift, and so niauy portions of the Illinoian drift area in Western Illinois, for tliey are bnilt np about to the level of the summits of the rock ridg-es. It is estimated that such areas embrace only aboiit 3,550 square miles. More than half the Illinoian drift area, embracing about 19,275 square miles, appears to have been filled to about two-thirds the capacity of the preglacial valleys and to have perhaps 100 feet of drift. There Is an area of nearly 7,000 square miles lying mainly in southern Illinois but embracing also portions of Stevenson, Winnebago, Ogle, Carroll, and Jo Daviess counties, in northwestern Illinois, where the average thickness can scarcely reach 50 feet, the valleys being filled only to one-third or one- fourth their full capacity. There remain about 8,000 square miles in south-central and southwestern Illinois in which it is somewhat greater than in the districts just mentioned and may average 75 feet. Summing up the above estimates in a tabular statement and averaging the results for the State, we have the following table: Distribution, by depths, of glacial drift in Illinois. Area. Depth if Depth of distrihuted drift. over entire State. 1 Square miles. 4,160 10, 975 3, 550 19, 275 8,190 6,924 Feet. 300 200 150 100 75 50 Feet. 23.50 41. 3.5 10.04 36.32 11.57 6.52 53, 074 129. 30 The above computations are necessarily less exact than those based upon borings, but the method may prove helpful in supplementing one based entirely on borings. It is some satisfaction to find that the results obtained by the two methods are not so widely discordant as to leave doubtful the general average thickness. As the computation just made represents the maximum estimate of thickness, it should be compared with the highest of the corrected estimates from borings. With this it is in essential agreement, being but 9 feet higher. The average thickness for AVERAGE THICKNESS OF THE DRIFT IN ILLINOIS. 549 the State ma)" safel)^ be placed at not more tliaii 130 feet and not less than 100 feet; probably it lies not far from midway between these amounts, or 115 ieet} ' In the above estimates everything which overlies the rock has been included, not only glacial drift, but residuary clay, alluvium, and loess. In order to ascertain the proporlion of till, a careful computation has been made from the records of 1,687 borings obtained within the the area covered by the Illinois lobe. These give the following results : Per cent. Till, including .ill glacial clays 69.38 Sand, gravel, and alluvium 25.25 Loess and associated silts 4.25 Buried soil, residuary clay, etc 1. 12 Total 100. 00 In this computation it is iirobable that the auiount of residuary material is Underestimated, since it is ouly occasionally recognized in borings. CHAPTER XIV. WELLS OF ILLINOIS. INTRODUCTION. lu the Seveuteeutli Annual Report of this Survey the writer has pre- sented a paper on the "Water resources of Ulmois," in which the wells are discussed in a general manner in connection with other water resom-ces. The data concerning artesian wells and the wells affording supplies for cities and villages are tabulated in that paper, but a large number of wells which do not admit of ready classification were necessarily omitted. The present discussion aims to present all the reliable records collected in the State which throw light upon the formations penetrated and the character of the water supply. CLASSIFICATION OF UNDEEGROUND WATERS. The classification of underground waters g-iven below seems to include the most important phases or classes of subterranean distribution to be found in this region. It has already been presented in nearly its present form by the writer in the Eighteenth Annual Report. In nearly all cases it is not difficult to decide from the description to which class a given well should he referred, and it has scarcely seemed necessary, in the detailed discussion which follows, to group the wells in classes. They are instead taken up by counties. However, a tabulated statement has been prepared setting forth the use made of the several classes of wells a.s sources for city water supply. The following are the principal classes of underground waters: Class I. — Grround water, supplied by direct percolation of the rainfall into the soil and substrata, and subject to but little lateral transmission and little hydrostatic pressure. The water level rises and falls with the degree of saturation by rains. Class 2. — Waters in close association with streams, as in valley bottoms, in which lateral transmission is great and hydrostatic pressure is small. It .5.50 WELLS OF ILLINOIS. 551 differs from tlie former class not only in the great lateral transmission, but also in being fed partly by stream percolation. The level rises and falls with that of the neighboring streams. This class should perhaps include the waters of sand plains and gravel plains which have no surface streams traversing them, for waters in such plains usually have great lateral trans- mission and but little hydrostatic pressure. Class 3. — Water included in porous beds of glacial di-ift or other non- indurated formations lying beneath impervious beds but without strong- hydrostatic pressure. Such water is supplied from more or less distant absorption areas and is less directly influenced by rainfall than the preced- ing classes. Class 4. — Water with strong hydrostatic pressure included in porous beds of glacial drift or of alluvium. This includes two subclasses, viz: («) Flowing wells; and (b) wells in which water rises nearly to the sm-face. Subclass (a) embraces wells to which the name "artesian" is considered applicable, while the term is not extended to wells of subclass (b). Class 5. — Streams in caves and subterranean passages in the rock, fed by sink holes and brooks and also by direct percolation from ground water. Class 6. — Rock water with bxit little current and slight hydrostatic pressure. Class 7. — Rock water under strong hydrostatic pressure. This includes two subclasses, viz: (a) Waters which overflow when tapped; (b) waters which rise nearly to the surface. Subclass (a) embraces wells to which the term "artesian" has long been applied, and it seems a convenient term for use if properly restricted, but its extension to nonflowing wells tends to mislead and confuse those interested in obtaining a flow of water.^ ' Discrimination in selection of records. — It should uot be Inferred that tlic averap'e depth of the wells reported in the ensuing discussion represents the average of all the wells that the region affords. Attention is directed chiefly to the deeper wells, since they throw more light than the shallow ones upon the structure of the formations penetrated and upon the supplies of water. The great majority of wells in the State are the seep or ground-water wells (class 1). They are sunk to depths of but 10 to 20 feet. In seasons when rainfall is normal or excessive such wells supply the needs of the residents, 'Compare Chamberlin, Fifth Ann. Eept. U. S. Geol. Survey, p. 131. 552 THE ILLINOIS GLACIAL LOBE. but iu seasons when the rainfall is deficient many of them fail, or yield but a small amount of water. The wells hei-e recorded are generally those which afford a supply of water iu seasons of drought as well as in rain}' seasons. The well records have been obtained largely from the drillers. In some cases there is uncertainty as to the reliability of such records, but as a rule the drillers are sufficientlv careful iu their observations to wan-ant the accej^tance of their statements. Records have, in mau}^ cases, been obtained from the owners of the wells, who were present during their excavation and often assisted in making the wells. The village wells have usually been recorded carefullv during the excavation or drilling, and thus have a value above those whose records are given from memory. The writer has rejected such well records as are thought to be unreliable, and has endeavored to reduce errors to a minimum. It is thought that the records here presented contain few serious errors, and that the general exposition of the subject and general conditions for obtaining water are set forth with a fair degree of accurac}'. The published well records in the Geology of Illinois are also included in this report and duly accredited. THE GEOLOGIC FORMATIONS. Since many of the wells enter rock, a map of the geologic formations is here introduced (PI. XXI) which was prepared by the writer to accom- pany a paper in the Seventeenth Annual Report. It follows in the main Prof. A. H. Worthen's map of Illinois, published in 1875, to accompany Vol. VI of the Geology of Illinois, but a few corrections have been made in northern Illinois based upon observations by Mr. Oscar Hershey and the writer. The portion covering western Indiana is based u^jon Dr. A. J. Phinnev's map of Indiana, published by this Survey in 1890.' The lime- stone formations of the northern and western parts of Illinois and the sandstones and sandv shales of the southern and southeastern parts are extensively utilized as a source for ordinary wells for household use. The limestones are also a source for artesian wells or deep wells having strong hydrostatic pressure. A few artesian A^ells obtain water from the sand- stones of southern Illinois. In northern and western Illinois the St. Peter and Potsdam sandstones are the sources of numerous artesian wells. The I i;ievciitb Ann. Kept. l". S. (i.ol. Survey, PI. LXIII. ■ruiSg o gi i ; ilsJ S 5 si'Si<| = iiJij5i.i«iiSi5oJg5s|| WELLS OF ILLINOIS. 553 Lower Magnesian limestone is also used for artesian supply. Portions of the Coal Measures yield brackish water, and for this reason they have not been extensively utilized for water supply. In some localities, however, it has been found necessary to make use of these formations because of no adequate supply from the drift or overlying- rocks. In such places the presence of beds yielding comparatively fresh water has been made known. In the detailed discussion which follows, the degree of development of the several rock formations is set forth. ATTITUDE OP THE STRATA. The attitude of the strata is very favorable for producing a strong hydrostatic pressure in deep wells throughout much of the State. A north- to-south section shows a gradual southward dip of the formations (see figs. 7 and 8), terminated at the south by an axis of upheaval which, as above noted, leads eastward across the southern end of the State from Gt-rand Tower to Shawneetown. The descent probably amounts to 2,500 or 3,000 feet in the 350 miles from the north to the south end of the State. There are slight undulations carrying the strata up or down 100 to 200 feet or more from a uniform grade, but so far as known no prominent west-to-east axis of upheaval crosses the State north of the one just noted, none adequate to' prevent the southeast passage of the water. East-to-west sections are less uniform in the inclination of strata than the north-to-south sections. Sections across the northern part of the State present two blocks of strata, each dipping gradually to the east, sejDarated by an abrupt fold or line of disturbance (see fig. 9). At this fold the block on the east rises abruptly several hundred feet above the neighboring portion of the western block. It is along this line of disturbance that the St. Peter and Lower Magnesian strata are brought to view on the Illinois and Rock rivers and on Elkhorn Creek. Its trend from the Illinois River northward is about southeast to northwest. Sections in the lead region indicate that it continues in subdued form some distance into southwestern Wisconsin. Its southward continuation from the Illinois is readily traceable as far as Livingston County by disturbances shown in coal shafts, as noted by the Illinois survey. Farther south its course is less definitely known. There is, over much of western Illinois, a gradual descent from the western border of the State to this line of disturbance. In the latitude of 554 THE ILLINOIS GLACIAL LOBE. Peoria it averages about 7 feet per mile, and is not greatly different in por- tions of the State farther north. The eastward descent across western "■^ H '.ft fSLANO CA- T MOUN£ s B 2 n := Q 00 1 en » g M 5? 3 E5= § ny*: coMSw /f 'yf £fi -/NGHAM 'KSONVILLE Illinois appears to rontinue gradual as far south as the Cap an Gr^s uplieaval, near the mouth of tlie Illinois, and, so far as known to the writer, WELLS OF ILLINOIS. 555 there is no marked disturbance along- the Mississippi north from that point. From the Cap au Grfes disturbance southward to the Ozark Ridge, in south- ern HHnois, a diflPerent field is found. Disturbances are frequent along- the Mississippi. There is also in this disti-ict a more abrupt descent in the floor of the Coal Measures within a few miles east of the Mississippi. Thus, in passing from the east bluff" of the river in western St. Clair County to Belleville a descent of 650 feet is made within a distance of 10 miles. ESSENTIAL CONDITIONS FOR ARTESIAN WELLS. Since the essential conditions for obtaining artesian wells have been discussed at some length by Prof T. C. Chamberlin in a report of this Sur- vey,^ only a brief outline of their conditions is here attempted. The essen- tial conditions for artesian wells are: (1) A suitable exposure of a porous rock in a humid region, i. e., a favorable absorbing area; (2) the extension of the porous bed from the absorbing area out underneath regions havino- a lower altitude, i. e., a favorable transmitting area; (3) a partial or full obstruction to the escape of the waters at a lower level than the absorbing area. The porous rock is usually confined between beds which are less porous and which act as a partial or complete obstruction to the escape of the waters. It is not necessarj^, however, that these beds should be per- fectly water-tight; indeed, such is rareh' the case. It is only necessary that the confining beds should be such as to prevent most of the water from escaping. In some cases the water contained in semiporous beds overlying the porous rock aids in preventing the escape of water from the porous bed at points between the absorbing area, or fountain head, and the well. In connection with this condition Professor Chamberlin remarks:'^ I conceive that one of the most favorable conditions for securing a fountain is found where thick, semiporous beds, constantly saturated with water to a greater height than the fountain head, lie upon the porous stratum and occupy the whole country between the well and its source. This is not only a good but an advan- tageous substitute for a strictly impervious confining bed. Under these conditions limestone strata reposing on sandstone furnish an excellent combination. This condition prevails extensively in northern Illinois. The absorbing area for the artesian waters of northern Illinois is found in southern Wis- consin, the porous rock thence dipping southward to northern Illinois. 'Fifth Ann. Kept. U. S. Geol. Survey, 1885, pp. 131-173. = Loc. cit., p. 140. 556 THE ILLINOIS GLACIAL LOBE. Between this absorbing area and the wells is a district in which the porous bed is overlain bv limestone or semiporous rock, and also by drift beds, which aftbrd much opportunity for absorption of water. These overljdng- beds, however, have altitudes fully as great as portions of tlie absorbing- area, and hence, when filled with water, the downward pressure equals or exceeds that of the upward pressure of water from the porous beds, and thus they prevent escape as effectually as a series of impervious beds. The -s-ariabilitv of head displayed by wells in northern Illinois which obtain their main supplj^ from the St. Peters formation is probably largely due to the influx of water from overlying beds in the district between the fountain head and the well. The main absorbing areas for the Potsdam and St. Peter formations are shown in PI. XXII, which is compiled chiefly from State geological maps and was first published by the writer in the Seven- teenth Annual Report of this Survey. A topogTaphic map of the St. Peter sandstone, showing also the dis- tribution of artesian wells and deep borings and of the principal areas where flowing wells are obtained from the drift, is presented in Pi. XXIII, a map already published in the Seventeenth Annual Report. The three sections in figs. 20, 21, and 22 illustrate the above statements concerning the attitude of the rock formations and correspond to the lines A — A, B — B, and C — C on PI. XXIII. The data used in figs. 7 and 8 are largel}' obtained from records of wells collected by the writer, but some of the data are from a report by Daniel W. Mead, bearing upon the liydrogeo- logy of the Mississippi Basin.^ The data in fig. 9 are largely based upon a special study by Prof. J. A. Udden of a line leading from Rock Island eastward across Illinois, which was made for the Illinois Board of World's Fair Commissioners.^ It brings out clearly the monoclinal fold separating the two blocks of eastward-dipping- strata just noted. For a more complete discussion of artesian-well conditions in Illinois, reference may be made to the report by the Avriter contained in the Seventeenth Annual Report of this Survey. Many records of wells appear in the detailed discussion below. ' Hydiogeology of tlie Upper Mississippi Valley and some of tlie adjoiniug Territory, by Daniel W. Mead, ('. E. : .lour. Assoc. Eng. Soc, Vol. XIII, No. 7, July, 1894. G8 pages, with G maps. -See Final Report Illinois Board of World's Fair Commissioners, 1895, pp. 115-1.'51. U.S. GEOLOGICAL SURVEY. MONOGRAPH XXXVIII PL. XXII & ST /f ^'VC^ $ O N 1 — '^ , — 3^«Qlesbo . liarU 50 fV — 1 0/ >■"' — :S5»fS"'\i >r: L / "^ .;<^ m . ^ T^ PM^'ii>ii'W^ 'runc^ rr- roiT HCKSa 15^^ h ■*' soiii ^TeeijiBfiy' ^Kewaunee r RiTJOD «^; ft) ftp: oJkuitowof- sfiebf^y^aii Fails Port ^Vashin;§lon 44 'conoM()Hcxr{ ni^yikesJpa I " / \rKcin 0ene Deiaygh.:'. -^ ■43' Kenosha Potsdcini .Simdstoiie ((.'anibi-iani (Outcropping or within reach of snrtace -switej Si. Peter sandstone (Lower Siltirian 1 92" ^rAIN ABSORBING AREAS FOR THE POTSDiUI AND ST. PETER FORMATIONS COMPILE]) CHIEFLY FROiM STATE GEOLOGICAL MAPS BY KRAiNHC LE\T':i{KTT 1896. Scale 2."^ O 25 .-iU 75 lOOMlLES JULIUS BIENS CO. N.Y i5sSffi£ n n •^ f< U K o o en jpii|5il^l=ii;i|iiii - c/: 2 j< .2 WELLS OF ILLINOIS. 557 RELATION OF THE DRIFT TO ORDINARY WELLS. The g-eneral relation of the drift to the ordinary wells of Illinois and western Indiana i§ set forth in PL XXIV. It will be observed that with the exception of a few counties in the northern and southern ends of Illinois the wells are largely obtained from the drift. This relation is shown in detail in the discussion which follows. GAS WELLS. Wells which yield an inflammable gas are found in many counties of the State, instances of which are presented in connection with the water wells. This gas in some cajses appears to be derived from the decay of vegetal matter contained in the drift, either in the form of peat and muck beds or as timber scattered through the drift. It is probable, however, that the underlying rocks are an important if not the chief contributor, m which case the pressure of the g'as within the drift is due to the resistance which compact drift beds offer to the escape of the gas. Not only the shales but certain limestones in this region have been found to contain gas. But it does not seem to have accumulated in such great quantities as in the gas fields of the neighboring States of Indiana and Ohio. It rarely reaches a pressure of 20 pounds per square inch. TABUIiATIOIf OF SOURCES FOR CITY AVATER SUPPIiY. The following table embraces all the cities and villages in Illinois hav- ing water works whose source of supply has been ascertained. It is based, in part, upon data collected by the writer, and in part upon data found in the Manual of American Water Works for 1897.' Through the aid of this publication the statistics have been properly rounded out and brought down to date. In towns with the letter "M" appended the Manual of Water Works is the authority. The wells are classified according to the scheme above outlined (pp. 550-551). Man^^ details concerning the city water supplies appear in the subsequent discussion by counties. ' The Manual of American Water Works, 1897, edited by M. N. Baker, Engineering News Pub. Co., New York. Contains the history and descriptions of the source and mode of supply, pumps, reser- voirs, standpipes, distribution sj'stems, pressures, consumption, revenue and expenses, cost, debt, and sinking fund, etc., of the water works of the United States and Canada. 55R THE ILLINOIS GLACIAL LOBE. Sources of water supply for towns in lUinois. Aleilo Alexis (M) Algonquin Alton Amboy Areola Atlanta Aurora Austin Avon(M) Barry Batavia(M) Beardstowu Belleville Belvidere Bement Bloomingtou Buckley (M) Buda Bushnell Cabery (M) Cairo Cambridge (M)... Canton Carbon Hill (M).. Carlinville Carlyle Carmi (M) Carrollton Carthage Centralia Chadwick Champaign Charleston Chats worth Chenoa Chicago Chicago Heights Chillicothc Cissna I'ark (M). Clayton (M) Clinton Collinsville Population in 1890. Source. 1,601 Kock, class 7. 562 Drift, class 3. 300 Spriug.s. 10, 294 River. 2,257 Rock, class 7. 1,733 Drift, class 3. 1,178 Drift, class 3. 19, 688 Rock, class 7. 4,051 Rock, class 7. 692 Rock, class 6. 1,354 Rock, class 7. 3,543 River (?). 4,226 Drift, class 4. 15, 361 Creek. 3,877 Rock, class 7. 1, 129 Drift, class 3. 20, 484 Drift, class 4. 433 Drift, class 4. 990 Rock, class 7. 2,314 Drift, class 3. 342 Well, 240 feet, class 3 ( ?). 10, 324 River. 940 Deep well, class 7 (?). 5,604 Rock, class 7. (?) Rock, class 7. 3,293 Creek. 1,784 River. 2,785 River. 2,258 Rock, class 7. 1,654 Rock, class 7. 4,763 Creek. (?) Rock, class 6. 5,839 Drift, class 4. ' 4,135 River. 827 Drift, class 3. 1,226 Rock, class 6. 1, 099, 850 Lake. (?) Rock, class 6. 1,632 Alluvium, class 2 (?) Drift, class 4. 1,033 Rock, class 6. 2,538 Drift, class 3. 3,498 Rock, class 7. WELLS OF ILLIT^OIS. Sources of water supply for towns in Illinois — Continued. 559 1^0 wn. Crescent (M) Danvers Danville Decatur Dekalb Delavan Des Plaines (M) Dixon Downers Grove (M) Dundee DwiK-ht Earlville . East Dubuque- - . East St. Louis-. - EfiHngUam Elgin Elnihurst (M) ... Elmwood (M) . . . Elpaso Eureka Evanston Fairbury Farmer City Farmington (M) . Flannigan (M) .. Forrest Forreston Freeport Fulton Galena Galesburg - . . Galva (M)... Geneseo Geneva Gibson Oilman Granite (M) , Grayville ... Greenville.-. Harvev Popnlatlou in 1890. Source. (?) Drift, class 4. 50.5 Drift, class 3. 11, 491 River. 16, 841 Eiver. 2,579 Eock, class 7. 1,176 Drift, class 3. 986 Rock, class 6. 5, 161 Rock, class 7. 960 Deep well, class (?). (?) Springs. 1,354 Drift, class 4. 1,058 |Rock, clnss 6. (.Drift, class 4. 1,069 Rock, class 7. 15, 169 River. 3,260 River. 17, 823 River. 1,050 Spring. 1,548 Rock, class 7. 1,353 Drift, class 3. 1,481 Drift, class 3. 12, 762 Lake. 2,324 Rock, class 7. 1,367 Drift, class 4. 1,375 Rock, class 7 (?). 384 '•Artesian -well," class (?). 1,021 Drift, class 3. 1, 118 Rock, class 7. 10, 189 J Alluvium, class 2. •^Rock, class 7. 2,099 Rock, class 7. 5,635 Rock, class 7. 15, 264 JRock, class 7. ^Drift, class 4. 2,409 Well, class ( ?). 3,182 Eock, class 7. 1,692 Rock, class 7. 1,803 Drift, class 3. 1,112 Drift, class 4. (?) River. 1,999 River. 1,868 Drift, class 3. (?) Rock, class 7.. 560 THE ILLINOIS GLACIAL LOBE. Sources of water supply for toiciis in Illinois — Coiitiimed. Town. Havana Henuepin Highland Park Hillsboro Hinsdale Hoopestown. .. Ipava Jacksonville .. Jerseyville . . . _ Joliet Kankakee Keitbsburg Kempton (JI). . Ke wanes Kirkwood (M) . Kuiixville Lacon (M) Lagrange Laliarpe Lake Forest . - . Lanark Lasalle . Lemont Lena (M) Leroy Lewiston Lexington (M). Lincoln Litchfield Lockport Macomb Macon Mackinaw Madison Marengo Maroa Masim MattooM May wood (M) . Mcndou Meiidota Popnlation in 1890. Source. 2, 525 /Alluvium, class 2. 'Drift, class 4. .->74 Rock, class 7. 2, 163 Lake. 2, 500 ■Springs. 1, 584 Rock, class 7. 1,911 Rock, class 7. 667 Rock, class 7. 12, 935 Rock, class 7. 3, 207 Rock, class 7. 23, 264 Rock, class 7. 9,025 River. 1,484 Alluvium, class 2. 201 Drift, class 3. 4,569 Rock, class 7. 949 Rock, class 6 ( f ). 1,728 Rock, class 7. 1,649 Well, class (f). 2,314 Rock, class 7. 1, 113 Drift, class 3. 1,203 Lake. 1,295 Drift, class 3. 9,855 iRock, class 7. ISprings. (n Rock, class 7. 1,270 Deep -n-ell, class (?). 1,258 Drift, class 3. 2,166 Alluvium, class 2. 1,187 Well, class ( ?). 6,725 Creek. 5,811 Creek. 2,449 Rock, class 7. 4,052 Rock, class 7. 819 Drift, class 3. 545 Drift, class 3. (?) River. 1,445 Drift, class 4. 1.164 Drift, class 3. 1, 869 Drift, class 3. 6,833 Drift, class 3. 2,076 Rock, class 7. 640 Rock, class 7 3, 542 Rock, class 7. WELLS OP ILLINOIS. Sources of ivater supply for towns in Illinois — Continued. 561 Town. Metamora Metropolis Milan Milford(M) Minonk Moline Monmouth Monticello Morgan Park Morris Morrison Morrison ville Morton Mount Cariiiel Mount Carroll Mount Morris Mount Pulaski (M) Mount Sterling Mount Vernon Moweaqua (M) Murphysboro Newton Nokomis Norwood Park Oak Park Ohio Oluey Onarga Orangeville Oregon (M) Oswego (M) Ottawa , Pana ParkEidge (M) Paris Pawpaw Paxton Pecatonioa Pekin Peoria Peru Petersburg MON XXXVIII 3(j Population in 1890. Source. 758 Drift, class 3. 3,593 River. 692 Eock, class 7. 957 Drift, class 4. 2,316 Eock, Class 7. 12, 000 River. 5,936 Eock, class 7. 1,643 Drift, class 3. 1,027 Eock, class 7. 3,653 Eock, class 7. 2,088 Springs. 844 Drift, class 3. 657 Drift, class 3. 3, 376 Alluvium, class 2. 1,836 Eock, class 7. 895 Eock, class 6. 1,357 Well, class ( ?). 1,655 Drift, class 3. 3,233 Impounded water. 848 Well, class ( ?). 3,880 Eiver. 1,428 Eiver. 1,305 Drift, class 3. (?) Eock, class 7. 4,771 Eock, class 7. 360 Drift, class 3. 3,831 Eiver. 994 Drift, class 4. 347 Eock, class 6. 1,566 \Yell, class ( ?). 641 Well, class ( ?). 9,985 Eock, class 7. 5,077 Drift, class 3. 987 Eock, class 7. 4,966 Drift, class 3. (?) Eock, class 7. 2,177 Drift, class 4. 1,059 Springs. 6,347 Drift, class 4. 41, 024 Drift, class 4. 5,550 Eock, class 7. 2,342 Alluvium, class 2. 562 THE ILLINOIS GLACIAL LOBE. Sources of icater supply for towns in Illinois — Continued. Pinekneyville . Pittsfield Piano (M) Pontiac (SI) ... Princeton Quincy Rantoul (M)... Riverside Rochelle Rock Falls Rockford Rock Island ... Roseville (M) . Rossville (M) . Rushville (M) . Sandwich Savanna Shannon Sheffield (M) . Shelby ville ... Somonauk(M) Springfield . . . . Staunton Sterling Stockton (M) . Streator Sullivan Sycamore Taylorville. ... Tolono(M).... Urbana Upper Alton . . Vandalia Venice Walnut Warren Warsaw Washington . . Waterloo Waterman (M) Watseka Wankegaii ... Population in 1890. Source. 1,298 Rock, class 7. 2,295 Rock, class 7. 1,825 Rock, class 7. 2,784 River. 3,396 Rock, class 7. 31, 494 River. 1,074 Drift, class 3. (?) Rock, class 7, 1,789 Springs. 1,900 Rock, class 7. 23, 584 Rock, class 7. 13, 624 River. 788 WeU, class ( ?). 879 Well, class ( ?). 2,031 Springs. 2,516 Drift, class 4. 3,097 Rook, class 7. 591 Rock, class 6. 993 Well, class (f). 3.162 River. 468 Well, class ( ?). 24, 963 Alluvium, class 2. 2,209 Impounded water. 5,824 Rock, class 7. 379 Well, class (?). 11, 414 River. 1,468 Drift, class 3. 2,987 Drift, class 4. 2,829 Drift., class 3. 902 Well, class (?). 3,511 Drift, class 4. 1,803 Alluvium, class 2. 2,144 River. 932 River. 605 Drift, class 3. 1,172 Rock, class 7. 2,721 Rock, class 7. 1,301 Drift, class 4. 1,860 Impounded water. 351 Well, class ( <). 2,017 Drift, class 4. 4,915 Lake. WELLS OF ILLIISrOIS. Sources ofivater supply for towns in Illinois — Continued. 563 Town. Population in 1830. Soi 368 Drift, class 3. 1,053 Rock, class 7. 451 Well, class (?) 1,622 Kock, class 6. 1,458 Lake. 1,576 Elver. 1,079 Lake. 1,683 Rock, class 7. 375 Springs. Waynesville (M) Wenona Western Springs (M) Wheaton Wilmette Wilmington Winnetka Woodstock Yorkville From the above table it appears that in 69 cities and villages, or about one-third of the number in Illinois now having waterworks, the supply is obtained from rock wells either flowing (artesian) or with strong hydrostatic pressure. Of the 250,000 inhabitants of these cities and villages it is prob- able that more than one-half are dependent upon the public water supply. In some cities and in many of the villages a large part of the population prefer to obtain their supply from private wells or cisterns, a preference which is due in part to inability to meet the city water tax and in part to objectionable properties of the water. It should be stated, however, that throughout much of northern Illinois wells of this class furnish wholesome and very palatable water. It should be noted that wells of this kind are extensively used in various industries in the city of Chicago and in several other cities in northern lUinois, the aggregate amouW of water thus obtained in Chicago approximating that furnished by the city waterworks. In contrast with the extensive use of this class of rock wells as a city supply is the use of rock wells having weak hydrostatic pressure. Only twelve villages, with a combined population of scarcely 10,000, are known to depend upon the latter class of wells. It is possible, however, that a few others reported in the Waterworks Manual may be of that class. Such wells rarely furnish an adequate supply for a large town. The table indicates that aside from Chicago, with its population of more than one million, there are 52 cities and villages, with a combined population of nearly 300,000, in which surface water constitutes the public supply. In Chicago the population is mainly dependent upon such water. 564 THE ILLINOIS GLACIAL LOBE, In the other cities, aud especially in the villages, private wells and cisterns are used extensively. Turning to di'ift wells, it is found that 22 cities and villages, with a combined population of about 100,000, obtain their public supply from wells in glacial di-ift which have strong hydi'ostatic pressiu-e, many of them being flowing wells. In 38 other cities and villages, with a population aggregating about 60,000, drift wells ai'e in use which display no marked hydrostatic pressure. There are only three cities with a population of more than 2,000 in which this class of wells constitutes the public supply, namely, Mattoon, Pana, and Paris. There are 9 cities and Aallages, with a combined population of about 50,000, in which the public supply is obtained from beds of alluvium. Among these cities Springfield has been included, its supply being from infiltration wells along the bank of the Sangamon River. The supply at Freeport is from wells sunk below the level of the Pecatonica River, and these may possibly be referable to class 3 rather than to tlais class. However, the material penetrated appears to be alluvial rather than glacial. DETAIIiEI) DISCUSSION. With this brief statement concerning the sources for supply in the cities of Illinois, we pass to the detailed discussion of wells by counties. The counties are taken up in the order of their numbering on PL XX. The discussion begins in the northern tier of counties and passes back and forth in successive tiers, terminating at the southern end of the State. The uuirlaciated comities at the southern end of the State are discussed as a single district and very briefly, though they present probably a greater variety of sources for water supply than almost any other area of equal size within the State. The writer's examination of that district has been too incomplete to enable him to treat adequately of its water resources. JO DAVIESS COUNTY. GENERAL STATEMENT. This county is situated in the extreme northwest corner of the State and has an area of 663 square miles. The greater part lies within the Driftless Area, the glaciated portion occupying only about 100 square miles on the eastern border. The cfriftless portion, however, is covered with a nearly continuous sheet of loess, the thickness of which along the borders of tlie WELLS OF JO DAVIESS COUNTY, ILLINOIS. 565 Mississippi will average about 20 feet, but the average for the county will probably not exceed 10 feet. Along the Mississippi Valley on the west borders of the county there is a filling of sand and gravel about 150 feet in depth, as shown by wells on the Iowa side at Dubuque and Sabula. The tributaries of the Mississippi in this county have been silted up to a level corresponding with the filling in the Mississippi Valley. The material in these tributaries is usually a rather compact clay. Wells in the valley of the Mississippi obtain water at depths of 20 to 40 feet without entering the rock. In the tributaries of the Mississippi a few wells obtain water from the clay deposits, but as a rule the residents depend upon either springs from the limestone blufi"s or wells sunk into the rock. The wells on the uplands in the unglaciated part, and to some extent in the glaciated part, obtain their water from limestone at depths ranging from 40 feet to 150 feet or more. Usually a good supply maybe obtained at less than 100 feet. In the glaciated portions of the county the drift is generally too thin to afi'ord strong wells. There is, however, just north of Stockton a preglacial valley filled to a depth of at least 140 feet, which furnishes strong wells, some of which overflow. Tln-oughout the county the water is of excellent quality, although very hard. The expense of sinking- wells to rock being heavy, many of the residents resort to cisterns for a water supply. Impounded water is also used quite extensively to supply the stock on farms. INDIVIDUAL WELLS. The city water supply at Galena, the county seat, is obtained from an artesian well sunk to a depth of 1,200 feet and obtaining its supply from the Potsdam sandstone. It has a head 85 feet above the surface and a capacity estimated a,t 166 gallons per minute. An analysis made by the State Board of Health appears in the Seventeenth Annual Report of this Survey.^ Wells are obtained in the vicinity of Galena from the limestone at depths of 60 to 200 feet. At East Dubuque the town well is artesian and has a depth of 940 feet. The water is obtained from Potsdam sandstone and has a head nearly 100 feet above the surface and a capacity estimated at 420 gallons per minute. Aside from the artesian well there are a few shallow wells obtaining their supply from the gravel and sand of the Mississippi Valley. 'Pnrt IT, pp. 820 and 827. 566 THE ILLINOIS GLACIAL LOBE. At Wan-en and in that ^-icinity the best wells are 50 to 150 feet deep and obtain water from the Galena limestone. The altitude being high (about 1,000 feet above tide), the water level in the wells is so low that windmills are usuallv employed to raise the water. A large pi'oportion of the residents of the village depend upon cistern water. The Manual of American Waterworks (1897) reports that a well has recently been sunk to a depth of 900 feet which furnishes the public water supply. No data were obtained concerning wells in other villages of the county, but a few records were obtained of wells in the glaciated poi-tion between Stockton and Nora. These usually enter rock at 20 to 30 feet, but occa- sionally the di-ift is thicker. In the preglacial valley referred to above, which passes in an east-west coui'se midway between these villages, several well records were obtained which are tabulated below: Wells in a preglacial valley north of Stockton. Owner. Altitude (above tide). Deptli. Head from surface. Mr. Keplinger A. A. Simmons Andrew Simmons... Charles Kappas Theodore Hopkins.. W. Legrand Mrs. M. L. Grouse. . . Mrs. M. L. Grouse. .. G. W. Curtis Frank Weighers Mrs. Emily Goomler M. Werkheiser Richard Oliver Feet. 930 950 950 950 940 940 940 930 950 935 970 970 970 Feet 50 72 77 105 134 135 40 140 96 110 135 85 60 Overflows. 10 feet below. 10 feet below. 10 feet below. 3 feet below. 3 feet below. Ovex-flows. Overflows. 15 feet below. 10 feet below. 35 feet below. 35 feet below. 35 feet below. The majority of the wells in the above list peneti'ate 50 to 70 feet of compact clay before entering a water-bearing bed, and at Mrs. Grouse's deeper well 130 feet of clay was penetrated. The last thi-ee wells in the list are situated on a low drift ridge and their sections show a larger propor- tion of gi'avel and sand than the wells on the plane sui-face. The strong hydrostatic pressure probably results from an absorption of water on the None of the wells in this list entered rock. neighboring higher land. WELLS OF STBPHBFSON COUNTY, ILLINDIS. 567 although they are all situated within 5 miles of the glacial boundary, and some of them within 2 miles. STEPHENSON COUNTY. GENERAL STATEMENT. Stephenson County is situated immediately, east of Jo Daviess County, on the north border of the State, with Freeport as its county seat, and has an area of 560 square miles. It is drained chiefly by Pecatonica River, which traverses its northern and eastern portions. With the exception of a few square miles in the northwest corner, this coimty is covered with glacial drift. The thickness of the drift is insufficient to conceal the main preglacial valleys, and extensive upland tracts have rock within a few feet of the surface. The average of the well sections reaching rock so far as collected are as follows: Forty-eight wells on uplands and slopes, 31 feet; 12 wells along preglacial valleys, 130 feet. Of these, 17 wells are in Freeport and vicinity, and average 50 feet.^ The drift, as already noted, is frequently aggregated in small knolls and ridges having a gi-avelly con- stitution. At such places it has exceptional thickness. Aside from the preglacial valleys and the knolls and ridges just refen-ed to, the drift is usually too thin to be depended upon as a supply for wells. Most wells in this county, as in Jo Daviess County, obtain water from the Galena limestone at depths ranging from 30 or 40 feet up to about 200 feet. Their average depth is somewhat less than in Jo Da^dess Coimty. In the preglacial valleys and in some of the drift knolls and ridges strong wells are obtained at convenient depths — 25 to 50 feet. The highest portions of the county are very thinly coated with drift, rock usually being entered at 15 to 20 feet or less. A few instances, how- ever, are reported in which the drift has a thickness of 80 feet or more. The lowlands are generally covered to a sufficient depth to afford an ade- quate supply of water without entering the rock; but there are small areas within the lowland districts in which rock is very near the surface. These contrasts in the thickness of drift, both on highland and lowland tracts, are set forth in the table of wells given below. ' Many of the well records were collected by Mr. Oscar Hershey during or prior to his connec- tion with this Survey. 568 THE ILLINOIS GLACIAL LOBE. INDIVIDirAL WELLS. The public water supply for the city of Freeport is obtained mainly from a series of tubular wells sunk to a depth of about 40 feet through the alluAaum and possibly through glacial deposits of the Pecatonica Valley. The supply of water is derived fi-om sand just above the rock. The Manual of American Waterworks (1897) reports that a part of the supply is from wells about 200 feet in depth, which enter the St. Peter sandstone. This sandstone is stated by Mr. Hershey to .set in about 110-130 feet below the surface of the Pecatonica flood plain at Freeport. Several private wells in Freepoi't have been sunk to the St. Peter sandstone, and tliis sandstone is occasionally encountered in wells in the north part of the county. Near Orangeville the St. Peter sandstone comes nearly to the surface. The waterworks supply for that village is fi-om a well 142 feet in depth, which is mainly through St. Peter sandstone. The public water supply at Lena is from a deep well, but the precise depth has not been ascertained. E.ock is usually entered in that vicinity at about 15 feet. In the vicinity of Kent rock is entered at about 30 feet. The railway well at Kent Station is 275 feet in depth and obtains its supply in lime- stone. The limestone ridge south of Kent has rock at surface, there being scarcely enough drift to form a soil. The following table of wells is made up largely from data furnished by Mr. Hershey: Table of well sections in Stephenson County, Illinois. Owner or location. Altitude T^...v*i, (above tide). ^"P"^' Baier & Ohiendorf, .at Free- port. J. Wareham, Freeport D. Hoover, Freeport Millner'B Brewery, Freeport. .. Klectric light plant, Freeport . Stover M'fg Co., of Freejiort. . V^inegar Works, Freeport Triple Factories, Freeport H. S. Gochenour, Freeport I ). Sweeny, East Freeport Feet. 765 770 (?) 780 760 7.55 750 770 825 760 Feet. 240 212 60 57 240 112 (?) (?) 80 50 Remarks. Enters St. Peter sandstone at 167 feet ; drift, 34 feet. St. Peter sandstone at 186 feet ; drift, 85 feet. Depth of drift, 35 feet. Strong vein of water in limestone ; drift, 30 feet. Drift, mainly loess, 30 feet. Enters St. Peter sandstone ; drift, 100 feet. Penetrates drift 85 feet. Drift, mainly loess, 38 feet. Rock entered at 6 feet. Wells in lOast Freeport 30 to 50 feet in depth do not ivacl] rock. WELLS OF STEPHENSON COUNTY, ILLINOIS. Table of well sections in Stephenson Comity, Illinois — Continued. 569 Owner or location. Altitude (above tide) . Depth. Hemarks. Sec. 23, T. 27, E. 9 E Feet. 750 765 (?) 900 825 (?) 820 840 785 800 800 790 770 770 900 840 850 850 850 785 775 775 800 850 850 850 825 800 900 850 850 819 900 Feet. 30 82 65 80 72 80 150 100 60 72 100 31 45 60 80 90 100 85 90 104 110 161 100 192 248 128 165 128 186 87 142 70 70 Rock not entered. Sec. 30, T. 27, R. 9 E W. H. Fulton, Rock Grove Enters rock at 62 feet. Rock entered at 20 feet. Drift in places, 80 feet. Enters rock a.t 10 fpet Sec. 25, T. 27, R. 8 E Sec. 17, T. 27, R. 7 E On a low gravel ridge. Enters rock at fi fftpt Sec. 29, T. 27, R. 8 E Sec. 31, T. 27, E. 6 E No rock entered. Sec. 7, T. 26, E. 7 E Sec. 12, T. 26, R. 7 E Enters rock at 20 ffipt Sec. 12, T. 26, R. 7 E Enters rock at 98 feet ; drift, gravelly. Enters rock at 10 feet. Enters rock at 3.5 feet NE. i sec. 7, T. 26, R. 8 E Sec. 7, T. 26, R. 8 E Sec. 17, T. 26, R. 8 E Sec. 6, T. 26, R. 7 E Sec. 13, T. 26, R. 7 E No rock entered ; drift, mainly clay. No rock entered; over old valley of Yellow Creek. Entirely fine gravel and sand. No rock; drift mainly sand. Enters rock at .50 ft^t^i Sec. 14, T. 26, R. 7 E Sec. 19, T. 26, R. 8 E Sec. 30, T. 26, R. 8 E Sec. 5, T. 26, R. 8 E Sec. 8, T. 26, R. 8 E Enters rock at 7fi fppit. County Infirmary Enters rock at 1^1 ft^R-t Sec. 13, T. 26, R. 7 E Enters rock nt fil fppf Sec. 12, T. 26, R. 7 E Sec. 14, T. 26, R. 7 E Enters rock at 175 feet. Enters rock at 183 feet; drift, blue till. Enters rock at 115 feet ; drift, variable. Enters rock at 141 feet; drift, variable. Enters rock at 112 feet; drift, variable. Enters rock at 140 feet; drift, variable. Enters rock at 70 feet; drift, variable. Enters rock at 120 feet; drift, mainly blue till. Mainly blue clay; rock at bottom. Clay, 25 feet; remainder sand and gravel; rock at bottom. Sec. 14, T. 26, E. 7 E Sec. 13, T. 26, E. 7 E Sec.24,T.26, R.7 E Sec. 36, T. 26, R. 7 E Sec. 20, T. 26, E. 8 E Sec. 21, T. 26, E. 8 E Mr. Bolton, Bolton Station Sec. 31, T. 26, E. 7 E WINNEBAGO COUNTY. GENERAL STATEMENT. Winnebago County is situated on the north border of the State midway between the Mississippi River and Lake Michigan, with Rockford as its county seat, and has an area of 5.52 square miles. The eastern portion of 570 THE ILLINOIS GLACIAL LOBE. the county is traversed from north to south by Rock River, the northwestern portion is traversed from west to east by the Pecatonica, and the southeast- ern portion from east to west by the Kishwaukee River. The portion of the county west of Rock River has generally a thin coating of drift, except in the preglacial valleys. The majority of wells on the uplands enter rock at less than 20 feet. There are, however, occasional wells located probably over tributaries of the preglacial Rock- or Pecatonica which penetrate 75 feet or more of drift without reaching the rock. Excel- lent exposures of the drift may be seen along the line of the Illinois Central Railway between Rockford and Freeport. Like the drift of Stephenson County, it is generally very stony and contains a considerable amount of gravel and sand. Much of this portion of the county is covered with a loess-like silt 4 or 5 feet in tliickness, which furnishes an excellent soil. The portion of the county east from Rock River can-ies a heavy deposit of drift, rock seldom being found at less than 100 feet, and it is probable that along the valley of Rock River and its immediate borders the thickness exceeds 300 feet, for borings to the north and south show that the rock floor of the preglacial valley stands 250 to 300 feet below the present stream bed. The drift of the eastern portion of the county embraces a sheet which extends but little west of Rock River and which, as indicated above, is referred to the lowan stage of glaciation. INDIVIDTJAL WELLS. A lai-ge number of well sections were collected by Mr. I. M. Buell during his investigation of the drumlins and bowlder distribution of Winne- bago and Boone counties. But few records have been obtained by the wi-iter. Mr. Buell has kindly turned over these well records for presenta- tion in this report, and they appear in the table below. They are chiefly found in the disti*ict east of Rock River. Table of well sections east of Rock River in Witmebago County, Illinois. Owner or location. Altitude. Depth. Kemarks. Ser, 14 T 46 R 2 E Feet. 900 850 900 Feet. 60 60 65 Largely sandy cUift; iio rock. Drift till; strikes rook. Brow of bluft'; uo rock; gravel, 20 feet; bine clay, 35 feet. WELLS OF WII^NEBAGO COUNTY, ILLINOIS. 571 Table of tvell sections east of Bock Kiver in Winnebago County, Illinois — Continued. Owner or location. Altitude. Depth. Eemarks. Feet. Feet. Sec. 15, T. 46, R. 2 E 800 65 Till with gravel at bottom. 750 30 Foot of blufif ; drift till; no rocli. Sec. 1, T. 45, R. 2 E 925 107 Eock entered at 40 feet. 900 120 Till, 65 feet; gravel, 16 feet; till, 10 feet; sand, 30 feet; no rock struck. Sec. 2, T. 45, R. 2 E 900 75 Mainly till ; upper part stony ; rock at bottom. Bottom of well in gravel. 900 100 900 110 Till, 75 feet ; remainder sand. Sec. 3, T. 45, R. 2 E 900 50 Eock at 50 feet or less. 850 180 Eock struck at 65 feet. Sec. 4, T. 45, E. 2 E 850 100 Brow of blufif; till, 80 feet; gravel, 20 feet ; no rock. Foot of blufif; gravel (partly cemented), 46 feet; 750 55 clay and sand, 9 feet; no rock. 750 65 Rock river bottom; till, 43 feet; sand, 22 feet; no rock struck. Sec. 15, T. 45, R. 2 E 850 55 In o^ravel at bottom 850 60 Rock struck at 57 feet. 850 60 Gravel at bottom. Sec. 22, T. 45, R. 2 E 825 35 Gravel at bottom Churcli N. of Arffyle -. 900 50 Sec. 32, T. 45, R. 2 E 825 45 Brow of blufif; gravel at bottom. Brow of bluff; ferruginous drift conglomerate. No rock ; drift gravelly. Entirely till ; no rock. Sec. 5, T. 44, R. 2 E 800 28 Sec. 8, T. 44, R. 2 E 825 32 825 90 825 50 Till; no rock. 825 40 Till with cemented gravel at bottom. 825 90 Sand at bottom. Sec. 17, T. 44, R. 2 E 825 60 Dug through till ; drilled through cemented gravel ; loose gravel at bottom. 825 140 Till, 100 feet; cemented gravel, 40 feet; no rock struck. 825 140 Similar to preceding, and 40 rods distant. Sec. 19, T. 44, R. 2 E 825 80 Till, 74 feet; gravel at bottom. No rock ; mainly gravel. Similar to preceding. Sec. 20, T. 44, R. 2 E 825 50 825 45 Sec. 32, T. 44, R. 2 E 850 103 Wood in gravel below till at 75 feet ; no rock struck. Till, 40 feet; sand at bottom. 850 107 850 98 Sand at bottom. 850 46 Eock struck at 45 feet. Sec. 7, T. 44, E. 2 E 800 75 No rock struck; much ferruginous drift conglom- erate in that vicinity. Sec. 18, T. 43, R. 2 E 775 30 Drift, 30 to 40 feet in that vicinity. 572 THE ILLINOIS GLACIAL LOBE. Table of well sections east of Bock River in Winnebago County, Illinois — Continued. Owner or location. Altitude. Deptt. Hem arks. Feet. Feet. Sec. 30, T. 43, R. 2 E 800 40 Mainly till; no rock. Largely gravel ; rock at bottom. Across road from preceding . .. 800 40 Sec. 34, T. 43, E. 2 E 775 95 No rock ; mainly till. Hills at higher levels in vicinity have thin drift. that James Rested, SE. part of 775 100 Drift, mainly till ; rock struck. county. Mr. Davis, SE. part of county. . 775 60 Drift ranges from 10 to 60 feet on the farm. Mr. Watson, SE. part of county 800 90 No rock struck. W. E. Corlett, S. of New Mil- 775 140 Bluff of Kishwaukee; no rock struck; quarries at ford. a higher point toward the east. Sec. 25, T. 43, E. 1 E 800 55 On gravel knoll : no rock. The waterworks station at Rockford is located near the base of the west bluff of Rock River Valley in the north part of the city. Five wells are sunk to the Potsdam sandstone, from which water rises barely to the surface (719 feet above tide). With a diameter of 6 inches, each well fur- nishes about 200 gallons per minute by pumping. The drift ranges from 125 to 190 feet in depth. The upper portion is sand and gravel, but the lower portion is largely blue clay. No wells have been sunk in the midst of the valley at Rockford of sufficient depth to reach the rock. The distance to rock is probably much greater than in the wells at the waterworks.^ At Pecatonica wells usually obtain water in the limestone at depths of 80 to 125 feet. The drift in that vicinity is but a few feet in depth. The waterworks is supplied from springs. . In the vicinity of Winnebago Village the distance to rock ranges from 20 to at least 80 feet. Wells are usually obtained without entering rock, though several have been sunk some distance into the rock. In the vicinity of Elida the drift is usually about 50 feet, and a few wells pass into the underlying limestone. West from Elida and also north- west, over an area of perhaps 50 square miles, wells usually obtain water in the rock at depths ranging from 40 to 100 feet. The drift in that locality is thin, seldom exceeding 20 feet. Mr. Buell, however, reports two wells in sec. 3, T. 26, R. 10 PI, 50 and 60 feet in depth, which do not strike rock. Another well in the same section, enters rock at 40 feet and is cairied to a depth of 110 feet. Still another well located on a di'ift knoll enters rock at 'The data from Eockford have been lurnished by Daniel W. Mead, C. E., of that city. WELLS OF BOONE COUNTY, ILLINOIS. 573 30 feet. In the neig-liboriug section on the north there are several outcrops of limestone, though one well in that section fails to reach rock at 106 feet. A well in sec. 1, T. 26, R. 10, 114 feet in depth, enters rock at 50 feet. In the northwestern one-fourth of the county rock is usually entered at slight depth except in a narrow belt along the Pecatonica and Sugar rivers. But here, as in the southwestern portion of the county, occasional wells on the iipland reach a depth of 80 feet or more before entering rock. BOONE COUNTY. GENERAL STATEMENT. Boone County is situated immediately eas't of Winnebago County, on the north border of the State, and has an area of but 290 square miles. Behddere, the county seat, is situated near the southern edge of the county_ It is drained chiefly by the Kishwaukee and its tributaries, which occtipy gravel plains leading westward from' the moraines of the "Wisconsin drift sheet in McHenry County. These gravel plains are in places a mile or more in width and afli'ord an abundance of water at shallow depth, wells seldom exceeding 25 feet. The di'ift is thinnest in the southern portion of the county, there being numerous quarries in the two townships on its south border. In the north- ern part of the county the drift is probably not less than 75 feet in average depth, and it may possibly be as deep as in the neighboring portion of Winnebago County, from which the list of wells in the above table was prepared. Water is usually obtained at depths of 30 or 40 feet in that portion of the county from beds of gravel or sand associated with the till, the greater part of the drift being a typical till. In this county the glacial drift with its bowlders is not covered by deposits of loess or other silt as in counties to the west, and the surface sheet of drift, like that of eastern Winnebago County, is referred to the lowan stage of glaciation. INDIVIDUAL WELLS. The city of Belvidere obtains its public water supply from a well sunk to a depth of 1,950 feet. The well is cased only to the limestone, 58 feet, and water is found at several horizons above the Potsdam (in which the well terminates) as well as in that formation. The head is but 6 feet below the well mouth, or 757 feet above tide. Though only 4 inches in diameter in its lower portion, it is found to have a capacity of 400 gallons per minute. The hardness of the water suggests that it is largel}' derived 574 THE ILLINOIS GLACIAL LOBE. from limestone. The jjrivate wells in this city usually obtain water from gi-avel at a depth of about 20 feet. A few in the south part of the city, outside the limits of the Kishwaukee gravel plain, are sunk to greater depth, but seldom exceeding 40 feet. At the village of Caledonia, wells usually obtain water from beds of gravel beneath till at a depth of 30 or 40 feet. The following table of wells on farms in the neighborhood of Caledonia will serve to illusfrate the varia- tions in depth in the northern part of the county. It will be noted that only two of these wells enter the rock, viz, those in sec. 30, T. 46, R. 3 E., and sec. 7, T. 45, R. 3 E. . Depth of rcells in northern Boone County. Peet. John Van Aiithrop, sec. 34, T. 46, R. 4 E 42 William Millard, sec. 35, T. 46, R. 4 E 34 William Smith, sec. 26, T. 46, R. 4 E 63 James Hinemau, sec. 26, T. 46, R. 4 E 60 Sec. 30, T. 46, R. 3 E. (rock at 50 feet) 150 Sec. 7, T. 45, E. 3 E. (rock at 54 feet) 110 Sec.4,T.45, E.3E. (several wells) 30-40 D. S. Kelly, sec. 3, T. 45, R. 3 E 35 J. F. Ramsey, sec. 3, T. 4,5, R. 3 E 30 John Church, sec. 2, T. 45, R. 3 E 35 E. F. Bailey, sec. 1, T. 45, R. 3 E 21 Philip Colieman , sec. 6, T. 45, R. 4 E : - 24 Peter Mclntyre, sec. 6, T. 45, R. 4 E 25 Peter Oleson, sec. 5, T. 45, R. 4 E 22 John Stall, sec. 4, T. 45, R. 4 E 76 J. Miller, sec. 3, T. 45, R. 4 E 63 Die Nelson, sec. 3, T. 45, R. 4 E 65 T. L. Bowman, eec. 3, T. 45, R. 4 E 48 Herbert Young, sec. 3, T. 45, R. 4 E 35 In Bonus Township, situated northeast from Belvidere, the wells on the upland between the Kishwaukee River and Piscasaw Creek in several instances reach a depth of about 60 feet without entering rock. Although rock is usually struck at comparatively slight depth in the southeast township (T. 43, R. 4 E.), a well at a cheese factory in sec. 15 did not reach rock at a depth of 83 feet. Several wells in sees. 8, 9, 16, and 17 of this township enter rock at depths ranging from 4 feet to 20 feet on an upland standing about 900 feet above tide. On Coon Creek gravel plain, in sec. 3 of this township, at an elevation less than 800 feet above tide, a well 45 feet in depth does not reach rock. A well at Mr. Rj^an's, in sec. 33, at an elevation about 775 feet above tide, is 86 feet in depth and .strikes rock at 33 feet. Wells in sec. 23 reach a depth of 30 or 40 feet without entering rock. WELLS OP McHElSrEY COUNTY, ILLINOIS. 575 In the soutliwest township of the connty, in the vicinity of Irene, wells are usually sunk into the rock, thoug-h the di'ift in places exceeds 30 feet. The Illinois Central Railway cutting-, immediately west of Irene, shows an extensive exposure of black soil containing moUuscan shells underneath a sheet of till. The soil appears to separate the lowan till sheet from the lUinoian in which case it is referable to the Sangamon interglacial stage. McHENRY COUNTY. GENERAX, STATBJEENT. McHenry County is situated immediately east of Boone, on the north border of the State, Woodstock being its county seat, and has an area of 624 square miles. Its western portion is di-ained by the Kishwaukee and tributaries westward to Rock River, while the eastern portion is drained southward through Fox River, which has its course near the eastern border of the county through a series of lakes and sloughs. This is one of the ■ most elevated counties in the State, several square miles on its northern border being above the 1,000-foot contour, while much of the county stands above 900 feet. The greater part of the county is occupied by a system of moraines fonned at the Wisconsin stage of glaciation, there being only a naiTOw sb-'ip on the western border of the county, scarcely a township in average width, which lies outside its outer morainic system. This is underlaid largely by a gravel overwash from the moraine, and is therefore of Wisconsin age. There are a few outcrops of rock near the Kishwaukee in the western portion of the county at an altitude about 800 feet above tide, but these appear to stand above the general level of the rock surface and represent probably the tops of j^reglacial ridges or hills. Several deep wells scattered widely over the coimty have shown the presence of a very thick deposit of drift. It is probable that the average depth is not less than 200 feet, or nearly twice the average depth of drift for the State. The wells for household use usually obtain water at moderate depth (20 or 30 feet), but wells for stock are often siink to depths of 100 or even 200 feet. Dairying being one of the principal industries of the county, a large number of farmers have sunk deep wells to supply their cattle. The records of only a few of these were obtained, but they are thought to be representative. 576 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. The northwestern township of the county (Chemung) is occupied chiefly by a gravel plain, in which wells are obtained at a depth of 25 to 35 feet. In the vicinity of Chemung, however, the wells encounter till, and their depth ranges from 20 feet to 70 or more, water being obtained in beds of o-ravel associated with the till. The railway well at Harvard, in the southeast part of Chemung Town- ship, is sunk to a depth of 900 feet, and is thought to terminate in the lower portion of the St. Peter sandstone. The following strata were penetrated : Section of the railway well at Harvard, Illinois. Peet. Yellow and blue till 36 Gravel and bowlders - 24 Sand and loose gravel 15 Coarse gravel 1^ "Hardpan" 12 Limestone ^^° Shale 85 Mainly limestone 3*5 Mainly sandstone -^^ The water is hard and is apparently largely derived from the limestone. It rises within 41 feet of the surface, or to an altitude 894 feet above tide. The well is cased only to the rock (102 feet), and has a diameter of 7 inches below the casing. The capacity is estimated at 90 gallons per minute. Many private wells are obtained in Harvard at a depth of about 25 feet. The west part of the village is on a gravel plain, with a sheet of water at 20 to 25 feet or less. The railway station and east part of the village stand on the slope of a moraine. In the township east of Chemung only one well record was obtained — that at the cheese factory in the village of Alden. This well reached a depth of 150 feet without entering rock, and has the following section: Section of well at a cheese factory in Alden, Illinois. reet. Gravel and sand 1" Blue till ^"0 Black soil Till of bluish color 33 It is probable that the soil struck at the base of the blue till marks either the junction between the "Wisconsin drift sheet and the lowan, or between the lowan and Illinoian. The well is on a moraine. WELLS OP McHENEY COUXTY, ILLmOIS. 577 In the vicinity of English Prairie post-office, in the northeast part of the county, there is an extensive gravel plain standing at an elevation slightly above 800 feet, in which occasional wells have been sunk to a depth of 150 feet without reaching rock, mainly tlu-ough gravel. At Woodstock, the county seat, a boring was made some years ago which struck a black soil at about 160 feet, beneath which was till, in which the well terminated at a depth of 180 feet. This soil, like that at Alden, probably marks the junction between the Wisconsin and lowan drift sheet, or possibly between the lowan and Illinoian. A well has been sunk in Wood- stock to a depth of 1,014 feet, but no accurate record of the strata penetrated appears to have been kept. The drift has a thickness of 230 feet. The well is said to terminate in sandstone, probably St. Peter. A water-bearing "sand rock" was entered at 825 feet. The water is reported to be soft and of a pleasant taste, and has a capacity of 150 gallons per minute from a j)ipe 6^ inches in diameter. The head is 60 feet below the surface. Many private wells in Woodstock and vicinity obtain water at depths ranging from 20 to 60 feet. They are mainly through till, though beds of sand and gravel occur. At Marengo the wells vary greatly in depth, those on the gravel plain along the Kishwaukee being but 20 to 25 feet, while those on the slope of the moraine in the south part of the city are often 60 to 80 feet, and occasionally 125 feet or more. So far as ascertained, no wells reach the rock. The drift is largely of gravelly constitution. A well belonging to Mr. P. T. Parkhurst, 100 feet in depth, penetrated a black muck at about 60 feet, from which inflammable gas issued. This muck probably underlies the Wisconsin drift sheet. A similar muck was struck on the farm of James Smith, 3 miles northwest of Marengo, at a depth of only 28 to 30 feet. The well stands on the slope of the outer moraine of the Wisconsin drift, slightly above the level of the older sheet of drift to the west. The soil in all prob- ability is at the base of the Wisconsin drift and above the lowan di'ift. At a cheese factory south of Marengo, in sec. 11, T. 43, R. 5 E., a well struck a black muck beneath blue till at a depth of 70 feet. As the well is situated on the moraine at about 70 feet above the lowan drift plain to the west, the soil probably caps lowan drift. At the village of Crystal Lake wells usually obtain water at depths of 50 to 70 feet and are largely through gravel. A well about 4 miles south- west of this village, in sec. 12, T. 43, R. 7 E., reached a depth of 210 feet MON XXXVIII 37 578 THE ILLINOIS GLACIAL LOBE. without entering rock. Water is obtained in gi-avel near the bottom, the greater part of the well section being till. In the vicinity of Cary wells are 60 to 100 feet in depth. Thej^ usually penetrate about 50 feet of dry gravel, beneath which is till, having water-bearing beds associated with it. At Algonquin, in the southeast corner of the county, an artesian well was sunk to a depth of 2,527 feet by the Illinois Condensing Company. Rock is struck at about 100 feet, and the well probably terminates in Pots- dam sandstone. At last reports the use of the well had been discontinued because of the corrosion of the pipes by the water. The public water sup- ply for this village is from springs. Many wells on the low ground obtain water at about 12 feet. A few have been bored to depths of 60 or 80 feet. They enter till after penetrating 12 to 20 feet of gravel. Occasional flow- ing wells are obtained in this vicinity. One in the valley of Crystal Lake outlet, about a half mile above Algonquin, has a depth of 60 feet. One at a blacksmith shop in the north part of Algonquin is 62 feet in depth, and has a head 14 feet above the surface. The bordering uplands rise to a height of aboutlOO feet above the level of the wells, and thus furnish an absorb- ing area of sufficient height to give a strong hydrostatic pressure. At South Riley, in the southwest part of the county, rock is usually entered below blue till at a depth of about 60 feet, or at an elevation not far from 800 feet above tide. Rock is also struck in several wells on the plain northwest from Marengo, in the southwest part of T. 45, R. 5 E., and northwest part of T. 44, R. 5 E., at a depth of about 60 feet. The general elevation of the region is about 850 feet above tide. A short distance east from these wells, however, a well on the farm of Mr. Alsing, sec. 35, T. 45, R. 5 E., reached a depth of 100 feet without entering rock. The following sections of farm wells are of interest because of their depth. They are located on or among the moraines of the Wisconsin drift sheet and none of them reach the rock: Deep drift boringn in xoutheastern McHenry Co Kitty. Feet. Moses Dinion, 2 miles south of Mareugo 123 K. Cooney, sec. 14, T. 45, E. 6 E 94 Harmony post-olBce 112 IraCnrtiss, near center of T. 43, R. 6 E 180 Well 80 rods east of preceding 86 W. Whitteinoie, T. 43, K.7 E ..; .■ 100 Mr. C^unuuings, near Hnntley 108 George Bunker, T. 44, Iv. 7 E 84 WELLS OF LAKE COUNTY, ILLINOIS. 579 The well at Mr. Cummings's overflows, although at an altitude about 900 feet above tide, and that at Mr. Whittemore's rises nearly to the sur- face. The absorbing area is probably on a moraine south of the wells, which rises to a higher elevation than that of the well sites. All the wells in the above list are mainly through till. In this connection it may be remarked that the moraines of this county appear to be composed chiefly of till, the principal exception being a gravelly area occupying a few square miles in the vicinity of Crystal Lake and thence eastward to Fox River. LAKE COUNTY. GENERAL STATEMENT. Lake County is situated in the extreme northeast comer of the State, on the border of Lake Michigan. It has an area of 490 square miles, and the county seat is Waukegan. The eastern portion of the county is traversed from north to south by the Des Plaines River, while the western portion is touched by Fox River. There are numerous lakes in the western half of the county, situated among the knolls and ridges of the Valparaiso morainic system. There are also extensive marshes and sloughs bordering these lakes and Fox River. The Valparaiso morainic system, which occu- pies much of the western half of the county, stands 200 to 300 feet above Lake Michigan. Other moraines, occupying a narrow belt between the Des Plaines and Lake Michigan, stand 100 feet or more above the lake. The drift of this county probably has an average thickness of more than 200 feet. The few wells which enter rock find a rock surface lower than the level of Lake Michigan, and several other deep borings penetrate below the level of Lake Michigan without entering rock. It is scarcely probable that the rock surface will average an elevation as great as the level of the lake (580 feet above tide). The upper portion of the drift, to a depth of about 150 feet, is chiefly a soft blue till, thought to be of Wis- consin age. Beneath this occasional borings in Lake, as in neighboring counties on the south and west, enter a hard till, thought to belong to the earlier stages of glaciation. The wells in this county usually obtain water at moderate depths, from gravel or sand associated with the till. Such wells, however, are often weak, and farmers have occasionally sunk to depths of 200 feet or more in order to obtain a larger supply. 580 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL "WELLS. At Waukegan the public water supply was formerly obtained from artesian wells, but since 1895 it has been obtained by pumping from Lake Michigan. Three wells were sunk to depths of 1,135, 1,600, and 2,005 feet, respectively. The tu-st well is reported by Mayor De Wolf to have obtained water of fair quality, though rather heavily charged with iron. The second well obtained an unpleasant water with bad odor, thought to be sulphurous. The wells were discontinued because of the hardness of the water, it being unfit for boiler use. The water also was found unsuit- able for sprinkling lawns, it being destructive to grass. The Lake Michigan water is not too hard for boiler use and in other ways is more satisfactory than the artesian water. The present intake is at a distance of 1,700 feet from the shore, but it is proposed to extend the tunnel to a distance of about a mile. At Lake Forest, wells which will yield 30 barrels per day are usually obtained at a depth of 40 feet or less. An artesian well at the residence of Hon. C. B. Farwell reached a depth of 960 feet and obtained a flow of water whose head was originally 50 feet above the surface, or about 125 feet above Lake Michigan. The drift at this well has a thickness of 160 feet. At Highland Park there are four artesian wells with depths of 1,800 to 2,200 feet. Mr. P. T. Dooley, a well driller, residing at this village, reports that wells 5 inches in diameter yield about 150 gallons per minute. A strong flow of water is obtained at about 900 feet and also at about 1,300 feet, as well as at lower horizons. The wells all flowed when first made, but at present scarcely reach the surface. The elevation of the well mouths is 110 to 115 feet above Lake Michigan, or 690 to 695 feet above the sea. The thickness of the drift is about 175 feet. At Milburn, in the north part of the county, on a plain between the Valparaiso moraine and Des Plaines River, several flowing wells have been obtained, and the wells on this plain usually show marked hydrostatic pressure. In some cases they are but 20 feet in depth, and rarely exceed 75 feet. Near Wauconda, in the western part of the county, several wells reach a depth of 70 or 80 feet, though shallower wells are common. WELLS OF LAKE AND COOK COUNTIES, ILLINOIS. 581 Near Lake Zurich, in the southwestern part of the count j, a few wells have been sunk to depths of over 200 feet without entering rock. One in the village of Lake Zurich reached a depth of 240 feet; one on the Fletcher farm in sec. 32, a depth of 230 feet, and one about a mile east of the village reached a depth of 297 feet. The latter has the following section : Section of loell near Lake Zurich^ Illinois. Feet. Yellow till 12 Blue till -- 88 Fine sand 197 Total '. 297 Gravel at bottom. A well driller states that much sand is found at de23ths of 100 feet or more beneath the crest of the Valparaiso moraine in the vicinity of Lake Zurich. At Barrington, on the south line of the county, two wells enter rock at 254 and 258 feet, respectively. They encounter considerable coarse gravel and cobble at about 160 feet The remainder of the section is mainly till. It is thought that this cobble bed occupies the junction between the Wisconsin and earlier sheets of drift, there being a change to a harder till beneath it. At Hainesville, in the north central part of the county, good wells are usually obtained at 80 or 90 feet, but one boring is reported to have reached a depth of 287 feet without obtaining water or entering rock. Another unsuccessful boring is reported to have been made at Grilmer, in the south central part of the county. It reached a depth of 213 feet without entering rock. At Deans Corners rock was struck at 290 feet. At Ravinia, in the southeast corner of the county, a well 186 feet in depth entered rock at 164 feet. COOK COUNTY. GENERAL STATEMENT. Cook County, of which Chicago is the county seat, has a wide frontage on Lake Michigan and extends back to distances of 15 to 30 miles from the lake, there being' much irregularity in the western border. It is one of the largest counties of the State, the area being 960 square miles. The Chicago River, whose main branch heads near the north line, flows south- ward near the eastern edge of the county and enters the lake through the 582 THE ILLINOIS GLACIAL LOBE. midst of the city of Chicago. Calumet River enters the county from Indiana, and after running westward to Blue Island, a distance of about 12 miles, it turns abi-uptly eastward. As previously noted, it formerly returned into Indiana and discharged at the head of the lake, but the present mouth of the river is at Soutli Chicago, in Illinois. The Des Plaines River flows southward from the north line of the county to Summit, having- an averagre distance of about 10 miles from the lake. It there turns " southwestward, leaving the county near the village of Lemont. The extreme northwestern portion of the county is tributary to Fox River. Drainage lines are poorly developed in both the elevated and the low-lying portions of the county, a feature which is characteristic of several counties in northeastern Illinois. The eastern portion of the county is a plain rising gradually westward to the borders of the Valparaiso morainic system. A large part of this plain stands only 10 or 15 feet above Lake Michigan, but on the western border its elevation is 40 to 60 feet or more. The plain is inteiTupted by a small drift ridge leading north a few miles from Blue Island. There are also drift ridges near the border of Lake Michigan, in the north part of the county, which rise to a height of 75 or 100 feet above the lake. The \)oy- tion of the plain standing within 60 feet of lake level, as already noted, has been occupied by Lake Chicago, whose discharge was southwestward through the "Chicago Outlet." The Valparaiso morainic system passes across the northwestern part of Cook County in a southward course, and, after crossing Dupage County, again enters Cook, occupying the southwestern borders of the county. This system stands in its higher parts fully 200 feet above the lake, and a small area in the extreme northwest part of the county reaches an elevation more than 300 feet above the lake. The drift is comparatively thin on much of the plain in Chicago and to the south and also along the Chicago Outlet, rock quarries being numer- ous and many instances of wells encountering rock at slight depth being found. There are, however, occasional wells which reach a level 100 feet or more below Lake Michigan before encountering rock. The available data seem to indicate that a buried valley enters the lake near Lincoln Park, whose, course can be followed for several miles back from the lake WELLS OF COOK COUNTY, ILLINOIS. 583 in a westward direction. Wells along this valley reach a level 115 to 125 feet below the lake before encountering rock.^ In the northern part of the county the rock surface appears to be gen- erally lower than in the southern, though the di-ift surface is higher. The thickness of drift is found to be in places 250 or even 300 feet, wliile the average probably exceeds 200 feet. Well sections reaching the rock have been obtained in all parts of the county at frequent intervals, except in the portion occupied by the Valparaiso moraine on the southwest border, or in about 800 square miles of the 960 embraced in the county. Sixty-two wells are found to show an average of 83 feet to rock, while 47 fail to enter rock at an average depth of 79 feet. The drift is largely a compact till, except in the northwest part of the county, where thick deposits of sand and gravel are frequently found beneath a sheet of blue till. Beds of sand or gravel are, however, associated with the till in sufficient amount to furnish a fair supply of water for wells. In a few instances wells in the northwest part of the county have penetrated a black soil below till at depths in some cases of over 100 feet. It is thought that the drift above such soils should be referred chiefly to the Wisconsin stage of glaciation. The soil may, however, in some instances be found below the lowan drift. INDIVIDUAL WELLS. In the city of Chicago several sources have been drawn upon for wells, but the public water supply is pumped from Lake Michigan. Since the drift is generally thin, there are onl}^ small areas where wells or rather where pure water may be obtained above the rock. The north part of the city, however, obtained water from the drift in the early days of settlement. The danger of contamination of such wells by sewage or otherwise is so great that their use is largely discontinued. The Lockport (Niagara) limestone, which underlies the city, has been drawn upon for water from the early days of settlement, but the use of water from this source is decreasing, in part because of danger from contamina- tion, and in part because of a sulphurous odor which often characterizes the water. Artesian wells have come into extensive use within the past thirty ' The position of this valley was noted first by Mr. Samuel Artingstall about 1886, while city engineer of Chicago. 584 THE ILLINOIS GLACIAL LOBE. years. The first well was sunk in 1864 in the northwest part of the city, on the hig-hest ground then within the city limits, and at an altitude of 31 feet above Lake Michigan, the precise location being- at the corner of Chicago and Western avenues. This well was sunk by a band of Spiritualists with a -saew to ^prospecting for petroleum, and it is reported that the site of the well was determined by Mr. James, a so-called medium, while entranced. Onl}- a small amount of oil was found, but at a depth of 711 feet a strong flow of water was struck, which rose to a height of 80 feet above the surface, or 111 feet above Lake Michigan. A second well only a few feet distant was sunk the following jem; which obtained a flow of water at a depth of 694 feet. The history of these wells is set forth in an interesting manner in a pamphlet entitled "History of the Chicago artesian well," by George A. Shufeldt, jr., issued by the Religio-Philosophical Publishing Association of Chicago in 1867. Mr. W. T. B. Read, who drilled the wells, still resides in the city.^ He reports that the head has decreased to such an amount that the water now stands 15 or 20 feet below the surface, or nearlj^ 100 feet below its original head, and that the wells are not in use. These wells apparently obtained their supply of water from the Galena limestone, the depth being insufficient to touch the St. Peter sandstone. Within a few years after the drilling of the wells just noted, several deeper ones were sunk in the city and strong flows were obtained. The earlier ones usually reached the St. Peter sandstone, but it is probable that much of then* supply came from hig-her strata. At the present time there are several hundred wells Avithin the city used by the various industries which demand large quantities of water. A large part of them penetrate only to the St. Peter sandstone, but many enter the underlying limestone and not a few reach the Potsdam sandstone. The deepest ones are about 2,700 feet. At this depth water is much more saline than in the St. Peter sandstone or Galena limestone. The disadvantage resulting from salinity will probably restrict the boring of wells in the future to depths of not more than 2,500 feet. The boring of so many wells within a limited area has led to such an excessive drain upon the rock strata that the head is ke^Jt below the normal, and an ovei-flow is now rarely obtained. The deepest drift encountered in Cook County, so far as known to the writer, is in a well, at Samuel Church's, near the center of the northwest ' At 950 West CliicMyd iivoniie. WELLS OF COOK COUiTTY, ILLII^OIS. 585 township (sec. 22, T. 42, R. 9 E.). This boring reached a depth of 315 feet without encountering rock or obtaining water. As the altitude there is about 825 feet, the boring reached a level only 70 feet below that of Lake Michigan. Another boring 5 rods distant obtained a strong well from glacial gravel at a depth of 170 feet. Between this well and the city of Elgin several wells are found to enter rock at depths of 220 to 240 feet. Two wells east of Elgin are reported to have passed through an old soil beneath the till. In one well the soil occurs at the base of the drift at a depth of 67 to 70 feet. In the other it occurs at about 165 feet, while the rock is entered at 192 feet. The wells in that vicinity penetrate a bluish till, but on the borders of Fox River a brown or reddish till is reported to extend to considerable depth. A well one-half mile west of Spaulding Station, 137 feet in depth, enters rock at 120 feet. The drift is mainly blue till. At Bartlett several wells reach a depth of 90 or 100 feet, mainly through till. At Ontarioville the wells of greatest strength are found at depths of 60 feet or more, and occasionally reach 140 feet without entering rock. In Palatine Township a large number of deep wells have been sunk, partly because of the difficulty in obtaining water at shallow depths and partly for the purpose of obtaining an overflow. At the time of the writer's visit to that township, in 1887, there were not less than 25 flowing wells. They are located principally in the central portion, near the village of Palatine, but occasional flows are obtained in other parts of the township as well as in neighboring townships. In the southwest part the altitude is too great for a flow, but several wells have been sunk there to depths of 150 to 180 feet without reaching rock. The following wells in the village of Palatine serve to show the differences in depth of the wells and the relation to rock strata: Flowing wells at Palatine, Illinois. Feet. Palatine town well, enters rock at 152 feet 160 Palatine railroad well, crust of rock at bottom 165 Palatine deep artesian well, enters rock at 147 feet 1, 656 Palatine Flax Mill, does not reach rock , 170 One block north of Flax Mill, not to rock 70 Palatine Cheese Factory, crust of rock at bottom 163 The well at the cheese factor}^, when first made, would rise into the second story, and that at the flax mill to a level 10 feet above the surface. 586 THE ILLINOIS GLACIAL LOBE. The other wells show a rise scarcely so high, though their mouths are at an equally low elevation. The well 70 feet in depth has a strong flow of chalybeate water. The strongest flow is from the cheese factory well — 60 gallons per minute. The crust of rock reported in these wells is perhaps a ferruginous incrustation of gravelly drift, such as is often formed above water beds in the (h'ift. In the deep artesian -well a strong flow of water is reported from a depth of 800 feet as well as from near the base of the drift. The collecting area for the shallow wells is thought to be in the portion of the Valparaiso moraine west and north of Palatine, which attains an altitude of 100 to 120 feet above the station. The superficial draiuag-e is very jjoor along this moraine, and much of the water must evaporate or find outlet by underground passages. The collecting area seems adequate for supply- ing the flowing well distinct. The following section of a well at the flax mill will illusti-ate the character of the deposits penetrated in each of the wells : Section of well at Flax Mill, in Palatine, Illinois. Feet. Yellow till - 10-12 Blue till - 25-30 Water-bearing gravel 3-4 Blue till, with occasional thin beds of sand and gravel, yielding water 125 The lower portion of the till is said to be more sandy than the upper. In the north part of Palatine Township there are several wells ranging in depth from 80 to 165 feet, which show strong hydi'ostatic pressure. On the lowest ground they occasionally rise within 5 or 10 feet of the top, and in two or more instances they ovei-flow. In the township adjoining Palatine on the south (T. 41, R. 10 E.) flowing wells have been obtained along a tributary of Salt Creek in sections 23, 25, and 26, at depths of 27 to 45 feet. Being so shallow they differ Init little from springs which occur in that ^'^cinity. A few deep wells have been made in the western part of this township. The following- section is from one in its northwest corner, at an altitude about 825 feet: Section of a icell in northwest jyart of T. 41, R. 10 E. Feet. Yellow till 10-15 Blue till 125 Black soil 4 Sandy till 50 Gravel with water 2 Total depth 195 WELLS OF COOK COUNTY, ILLINOIS. 587 At Arlington Heights a well drilled to a depth of 800 feet penetrates 128 feet of drift. No further data concerning the well were obtained. A well in this village penetrated a black soil beneath blue till at a depth of 70 to 75 feet, beneath which it entered another sheet of till. A well 2^ miles north of Arlington Heights entered rock at a depth of 195 feet. At Des Plaines Village, which is situated on a gravelly plain, wells penetrate about 12 feet of gravel before entering till. Some obtain their supply in this gravel, others from gravel associated" with the till. The depth seldom exceeds 30 feet. The public sup^jly is from an 8-inch well 200 feet in depth.^ A well on the farm of John Back, near Schermerville, 162 feet in depth, enters rock at 147 feet. In the Adllage of Schermerville wells are often 60 feet, and in some instances over 100 feet in depth, and obtain water from gravel beneath the till. At the village of Oak Gt-len several flowing wells have obtained water either near the base of the drift or in the upper part of the underlying limestone at depths of 90 to 120 feet. Mr. F. N. Hoffman's well, 118 feet in depth, struck one water vein in gravel at 78 to 80 feet and another at the top of the limestone at 114 to 118 feet. Water in this well rises 4 feet above the surface. A well near Oak Glen, in sec. 25, 160 feet in depth, does not reach rock, though its mouth is scarcely 60 feet above Lake Michigan. At Park Ridge, at an altitude 660 feet above tide, an artesian well enters rock at 103 feet. The drift is mainly till. No further data Avere obtained. A well about 3 miles north of Park Ridge at slightly higher altitude enters rock at 110 feet. At Winnetka, at the residence of Mr. Lloyd, a well 1,570 feet in depth enters rock at 150 feet. The water rises to a level nearly 40 feet above Lake Michigan. Wells are obtained in this callage at depths of 20 to 50 feet in beds of gravel associated with the till. At Wilmetterock is entered at about 140 feet, or nearly 100 feet below the level of Lake Michigan. A deep well has a head about 20 feet above the lake level. No further data were obtained. An artesian well at Evanston, 1,602 feet in depth, enters rock at 72 feet, or about 42 feet below the level of Lake Michigan. Water rises to a ' Manual of American Waterworks, 1897. 588 THE ILLINOIS GLACIAL LOBE. height 34 feet above lake level, or Gl-t feet above tide. The well reaches the Potsdam sandstone. An analysis of the water is presented in the Seventeenth Annual Report of this Survey.-^ The temperature of the water is 61.7 degrees Fahr. ]\Iany wells are obtained in this city at a depth of 35 feet or less near the bottom of the beach sand. The peaty deposits which occur at that horizon in some cases g'ive the water an unpleasant odor. The use of private wells is decreasing, being supplanted by the public supplj" which is pumped from Lake Michigan. In the vicinity of Niles Center several wells strike rock at depths ranging from 85 to over 100 feet. T^e gravel and sand of the lake beach is 8 to 12 feet in depth. The underlying glacial di'ift is mainly till. At Morton a well 115 feet in depth enters rock at about 100 feet. The di'ift is mainly blue till. In Bowman-sdlle and vicinity several wells near the Chicago River reach a depth of 80 feet Avithout striking- rock. In some instances they penetrate about 20 feet of beach gravel. A well at Rose Hill Cemetery, near Bowman ville, strikes rock at 100 feet. The upper 30 feet is gravel and sand, beneath which is a compact till extending to the rock. In sevei'al suburbs in the northwest part of Chicag'O rock is struck in artesian wells at 60 to 100 feet, as follows: Drift in artesian wells in northtcest part of Chicago. Feet. Jeflerson Park 68 Irving Park 79 Montrose 60 Norwood Park 90 Near County Infirmary 71 Same locality 101 Oak Park 65, 85, and 45 Near Cragin 20 111 all of these wells the greater part of the drift is blue till. The beach gravel and sand seldom amount to more than 5 or 10 feet. A well at River Park, near the Des Plaines RiA^er, 115 feet in depth, enters rock at 100 feet. A well at Turner Park obtains Avater from sand below till and just above the rock at a depth of 80 feet. Mr. Koch, near Dunning, has a Avell 114 feet in depth which did not reach rock. "Wells in the vicinity of Galewood, 60 feet in depth, are mainly through till and do not reach rock. Wells at MayAA'Ood, 40 feet in depth, do not reach rock, 'Part II, p. 827. WELLS OF COOK COUNTY, ILLINOIS. 589 but within 2 miles west of Maywood rock is struck at about 30 feet. The Manual of American Waterworks (1897) reports that the public supply is from an artesian well. A well in the Des Plaines valley near the Twelfth street bridge does not reach rock. At Riverside the water supply is obtained from artesian wells about 2,200 feet in depth, which reach the Potsdam sandstone. The supply is partly from the St. Peter and other strata above the Potsdam. The wells originally overflowed, but the head is now 20 feet below the surface, or about 600 feet above tide. With a diameter of but 3J inches, the capacity of one of these wells is estimated to be more than one million gallons per day. At Lagrange the public supply is from artesian wells, but no data were obtained concerning their depths and capacities. In the east part of the village a flowing well is obtained from the drift at a depth of 21 feet. Rock outcrops within the limit of this village at a higher elevation than the mouth of this well. On the plain east of Lagrange rock is frequently struck at about 20 feet. The drift there is mainly a blue clay, there being only 5 or 6 feet of yellow clay at surface. In some cases sand and gravel occur just above the rock. West of Lagrange, in the vicinity of Western Springs, wells often reach a depth of 40 or 50 feet without entering rock. Borings in the vicinity of Summit show the depth to rock to range from 10 feet or less to fully 40 feet. The beach gravel in the south part of the village is shown by a gravel pit to have a depth of 20 feet. Beneath this gravel is blue till. On the plain southeast from Summit several wells are sunk 45 to 55 feet without reaching rock. At Washington Heights a well at Klein's Hotel enters rock at 70 feet, penetrating the following beds: Section of icell at a hotel in Washington Heights. Feet. Gravel 3 Yellow till 5 Blue till 63 Limestone 3 Other wells are obtained in that vicinity at shallower depths. The public water supply is from a deep well.^ A well at Morgan Park, on the crest of the Blue Island till ridge, 1,046 feet in depth, has a head 594 feet above tide. Limestone is entered at a ' Manual of American Waterworks. 590 THE ILLINOIS GLACIAL LOBE. depth of 163 feet, or about 100 feet below the level of Lake Michigan. The well record indicates a soft till extending- fi'om the surface to a depth of 86 feet, beneath which there is a harder material called shale, but perhaps a till, 77 feet in depth. Another well in Morgan Park is reported to have struck limestone at a depth of only 90 feet. At Riverdale rock is entered at about 45 feet, at Dolton at 35 or 40 feet, and in the vicinity of Harvey at 20 or 25 feet. The public water supply at Harvey is obtained from deep wells, one of which derives its water from the St. Peter at 1,300 feet and another terminates in Potsdam at 2,075 feet. At Blue Island wells usually reach water in sand, connected with the lake occupancy, at a depth of about 25 feet. On "Lanes Island," in the Sag outlet, several wells reach a depth of 30 feet without entering rock. After penetrating 4 to 8 feet of sand they are mainly through till. At the village of Worth wells usually obtain water at about 16 feet in sand below till. Rock is exposed along the' Sag outlet in that vicinity at abotit the level of Lake Michigan. A well 4 miles east of Worth, in sec. 23, T. 27, R. 13 E., reaches rock at 55 feet. The drift is mainly till. On the island-like tract of moraine between the Sag outlet and Des Plaines, northwest of Worth, several wells reach a depth of about 80 feet without entering rock. They are mainly through blue till. On the Valparaiso moraine, in the south part of Cook County near Alpine, several wells have a depth of 80 feet without entering rock. Small amounts of inflammable gas have been found in some of these wells. In the vicinity of Matteson and northward in T. 35, R. 13 E., wells frequently reach depths of 50 to 65 feet without entering- rock. In the vicinity of New Bremen, in T. 36, R. 13 E., the wells are frequently 75 feet in depth and obtain water in gravel beneath the till. In the vicinity of Gleuwood wells along the beach penetrate 8 to 12 feet of gravel before entering till, and strike rock at about 30 or 35 feet. A flowing well was obtained by Mr. Winterhofli'e on his farm in sec. 6, T. 35, R. 15 E., at a depth of 75 feet without reaching rock. It was through till the entire depth. A neighboring well at Lewis Peter's enters rock at 85 feet, but the water level is 14 feet below the surface. Another well, in sec. 12, T. 35, R. 14 E., strikes rock at 85 feet and there obtains water, which WELLS OF DUPAGE COUNTY, ILLINOIS. 591 rises within 2 feet of the surface. Still another well, in sec. 7, T. 35, R. 15 E., only 60 feet in depth, encountered rock at the bottom, which may possibly have been a bowlder. The public water supply for Chicago Heights is obtained from four wells about 200 feet in depth located on the plain north of the village. The head is not sufficient to cause an overflow. The drift in the vicinity of this village is but 20 or 30 feet in depth and some of the private wells enter the rock; occasionally they are sunk to a depth of 80 or 90 feet. In the dis- trict east of Chicago Heights, as far as the State line, wells are usually obtained at a depth of about 35 feet, from g-ravel below till. DUPAGE COUNTY. GENERAL STATEMENT. Dupage County is situated west of the middle portion of Cook County, and has an area of but 340 square miles. Wheaton, the county seat, is situated near its g-eographic center. Its di-ainage is southward, the eastern border being tributary to Salt Creek and the middle and western portions to the East and West Dupage rivers, respectively. Like the portion of Cook County on the north, it is poorly drained, although stand- ing much above the bordering plain on the east. The eastern two-thirds of the county is occupied by the Valparaiso moraine, which carries numerous sloughs and basins among its knoHs and ridges. It affords excellent pas- ture lands and is extensively used in dairying, the leading pursuit of the county. On the dairy farms wells are frequently sunk to depths of 100 feet or more. The thickest drift section obtained is 162 feet, and 20 wells which reach rock show an average depth of 86 feet, while 17 of the deep wells which fail to reach rock show an average depth of 94 feet. From these sections, which are distributed widely over the county, the thickness of the drift may be inferred to average not less than 100 feet. The drift is thin- nest in the southwestern portion, on the borders of the West Dupage Kiver, where numerous quarries of limestone have been opened. Rock also comes to the surface near Elmhurst, in the southeast part. The drift in this county, as in northwestern Cook County, consists mainly of a blue till, but beds of sand and gravel are associated with the till at various levels and supply the water for wells. 592 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL AVELLS. Ill the northwestern township of the county, sections of thi-ee deep wells were obtained near Wayne, one of which in sec. 7, 105 feet, and one in sec. 8, 150 feet, in depth, do not reach rock, but one in sec. 33 enters rock at 162 feet. In the first two wells a large amount of sandy material was penetrated, but the third well penetrated nothing but till. In the middle township of the north tier several wells have been sunk near Roselle to a depth of 100 feet or more without entering rock. The majority of them are mainly through till. In the northeast township several flowing wells have been obtained in the vicinity of Itasca at shallow depths along a tributary of Salt Creek. The depths are but 20 to 30 feet, and the water rises scarcely 5 feet above the surface. There are also numerous shallow flowing wells along Salt Creek between Salt Creek Station and Elmhurst. It should be noted that this flowing-well district is adjacent to that of Cook County, discussed above. The altitude is 75 feet or more lower than at Palatine, being scarcely more than 650 feet along Salt Creek Valley, and about 690 feet at Itasca. Neighboring portions of the Valparaiso morainic system on the west rise fully 100 feet above the wells at Itasca, and it is probable that this moraine constitutes the absorbing area. A well at Benson ville, about 2,000 feet in depth, penetrates 97 feet of di-ift. No further data concerning the well were obtained. At Elmhurst records were obtained of two wells which strike rock at 70 and 98 feet respectively. Within a mile west of these wells a limestone quarry is opened at a level only 15 or -20 feet Delow the well mouths. About 3 miles south also a quany is opened on the blutf of Salt Creek. The public water supply is pumped from a spring about 3 miles distant from the town.^ Along the valley of Salt Creek, south from Elmhurst, wells are in jjlaces sunk to a depth of 50 feet, mainly through gravel. At the village of FuUersburg, however, wells obtain their supply of water in gravel at a depth of but 12 feet. At Hinsdale the public water supply is obtained from a well 864 feet in depth.. This is reported by the Manual of Ameiican Waterworks to aff'ord 1,000,000 gallons per day. The last edition of this manual reports a ' Manual of American Waterworks, 1897. WELLS OF DUPAGE COUNTY, ILLINOIS. 593 second deep well in use. The drift in the vicinity of Hinsdale is about 100 feet in depth and is mainly till. On the moraine west and northwest from this village several wells show the drift to be over 150 feet in thick- ness. One at a brickyax-d, in sec. 10, T. 38, K. 11, 190 feet in depth, enters rock at 159 feet; another near Clarendon Hills, 160 feet in dejath, does not enter rock. In each of these wells and in all the wells in that vicinity the drift is mainly a blue till. In the well near Clarendon Hills a very hard till was entered at a depth of 130 feet, which is perhaps an older deposit than the soft till above it. In the vicinity of Downers Grove several wells have been sunk to a depth of over 100 feet without entering rock. One well enters rock at a depth of 130 feet. In these wells sand is usually found below the blue till at depths of 100 to 120 feet. The Manual of American Waterworks (1897) reports that the public water supply is from two 10-inch deep wells. Near Lisle the drift is of gravelly constitution, and wells are usually obtained at about 50 feet. A well south of the village, in section 12, is 157 feet in depth and entered rock at aboiit 100 feet. This well was mainly through till. At Wheaton the public water supply is from a well 178 feet in depth and 10 inches in diameter, which is estimated to yield 300 gallons per minute. The limestone was entered at a depth of 116 feet. About 2 miles northeast of Wheaton, at an equally high elevation (750 feet), rock was entered at a depth of only 70 feet. Several wells have been sunk in the vicinity of Prospect Park and Lombard, which obtained water from gravel at about 50 feet. The di-ift in that vicinity is gravelly. In the vicinity of Turner Junction wells are occasionally sunk to a depth of about 100 feet without encountering rock. A well 3 miles south- west of the village entered rock at a depth of 116 feet. A deep well has been sunk by the Chicago and Northwestern Eailway Company at Turner Junction, but no data concerning it have been obtained. At Naperville wells usually reach water in gravel at a depth of about 30 feet. The drift east and south from this village is gravelly. It ranges in thickness from a few feet up to 100 feet or more. In several places near Naperville limestone quarries have been opened. West from Naperville in the vicinity of Eola the drift is about 100 feet in depth, mainly till. MON XXXVIII 38 594 THE ILLINOIS GLACIAL LOBE. KANE COUNTY. GENERAL STATEMENT. Kane County is situated west of Cook and Dupage, and lias an area of 540 square miles. It includes the tlll•i^^ng• cities of Elgin and Aurora, and its countv seat is Geneva. Fox River flows in a southerly course tlu-ough the eastern part of the county and is the line of discharge for most of the drainage. The greater part of the count}'' has such imperfect drainage that large areas have been artificially drained. It is in the center of the great dairy district of northeastern Illinois, and the greater part of the county is devoted to dair^^ng^ Numerous deep wells have been sunk on the farms, some of them reaching depths of over 200 feet before encountering rock, but in the southeastern part of the county rock is exposed extensively in the bluffs of Fox River and is struck at comparatively shallow depths in the wells. The portion of the county north from the latitude of Geneva is, as previously described, largely occupied by a complicated system of morainic belts, but the southern portion of the county has generally a nearly plane surface. These moraines were formed at the Wisconsin stage of glaciation and, like the Valparaiso morainic sj^stem to the east, consist largely of a soft blue till. In several of the deep wells a black soil has been found beneath the blue till, and under this soil a hard till is penetrated. This liard till is apparenth' of much earlier age than the di-ift of the Wis- consui stage. INDIVIDUAL WELLS. In the northwest township records were obtained of several wells near the village of Hampshire Avhich reach a deptli of over 100 feet without entering rock. A well at the brick yards in Hampshire is 102 feet, and one at the Warner Lock Company factory is 118 feet, each being mainly tlu-ough blue till. ( )u a farm near Hampshire one well reached a depth of 180 feet. On the crest of a moraine east of Hampshire, near Briar Hill Station, at an elevation 975 feet above tide, a Avell 175 feet in depth is entirely tlu-ough till except one foot of sand at the bottom. On this same moraine records of several wells were obtained which find water in abiui- dance at a depth of 20 to 35 feet, and the great majority of wells in the township are less than 40 feet in deptli. WELLS OF KANE COUNTY, ILLINOIS. 595 In the middle township of the north tier the following- records of deep wells were obtained: Deep drift wells in northern Kane County. Feet- Mr. Kelly, sec. 32 130 Mr. Roch, sec. 20 , 161 Mr. Huuter, sec. 21 106 Near Gilbert Station, in sec. 14 293 In the last of these wells an old soil was penetrated at the base of the blue till, at a depth of 180 to 183 feet, beneath which was a hard till extending to the rock, which was entered at 217 feet. At Dundee, in the northeast township of the county, wells on the gravel terrace along Fox River are about 60 feet in depth- The public water supply is obtained from springs, but in the part of the village east of Fox River private wells are still in use. Mr. Francis Perry obtained a flowing well in Fox River Valley north of Dundee, near the top of the limestone, at a depth of 181 feet. An old soil was struck at about 155 feet. Water will flow from a pipe 16 feet above the surface. This well is but a short distance from the flowing wells in McHemy County, near Algonquin, reported above. The city of Elgin obtains its public supply by pumping from Fox River. There are, however, many private wells within the city, and a few deep artesian wells. The wells usually obtain water without entering rock at depths of 50 feet or less. The thickness of the drift in a well at the Elgin Shoe Factory is 123 feet, and an old soil was struck at 108 to 113 feet. The drift above the soil is mainly gravel and cobble, but below it is a red- dish till. Usually rock is struck at a depth of less than 100 feet. The following' data concerning- artesian wells were furnished by W. S. Gamble, city engineer. A well at the Elgin Watch Factory, at an elevation 715 feet above tide, has a depth of 2,026 feet and a diameter of 6 inches. It obtains sulphurous water from St. Peter sandstone at 650 to 700 feet, and soft water from Potsdam at 2,024 feet. A well at the Plospital for the Insane, at an altitude 735 feet above tide, has a depth of 2,230 feet. This also obtains water both from the St. Peter and the Potsdam sandstone. The Elgin Creamery Company have a well 1,400 feet in depth, which obtains water from the Galena limestone at 487 to 514 feet, and from sand- stone at 650 to 700, 972, 1,208, and 1,398 feet. The upper veins are more sulphurous than the lower. The Illinois Condensing Company have a well 596 THE ILLINOIS (JLAOIAL LOBE. 1,876 feet in depth, which aijparently obtains the greater part of its water from the St. Peter sandstone at 650 to 700 feet. The heads at the several wells vary from 716 to 742 feet above tide, the lowest head being at the creamery and the higliest at the watch factory well. An analysis of the water from the well at the Hospital for the Insane is published in the Seventeenth Annual Report of this Survey.^ A well on the farm of Judge Wilcox, northwest of Elgin, in sec. 4, T. 41, R. 8 E., 127 feet in depth, passed through an old soil at 111 to 114 feet and obtained water without entering rock. The altitude at the well is about 125 feet above Fox River Valley at Elgin, or 850 feet above tide. Sections of thi-ee deep wells were obtained in the township west of Elgin, as follows : Deep drift wells west of Elgin, Illinois. Feet. Mr.Eussell, sec. 12, altitude 825 feet 100 T. Read, see. 32, altitude 925 feet 219 Well in sec. 35; altitude 900 feet 146 None of the wells enter rock, and in each well the drift is mainly a blue till. In the last one an old soil w^as passed through at 131 to 137 feet. In the next township to the west, T. 41, R. 6 E., several flowing wells have been obtained on a plain between morainic ridges at an altitude about 865 to 880 feet, and at depths ranging from 56 to 86 feet, as follows: Floioing icellsfrotn drift in western Kane Comity. Feet. Sec. 3, altitude 875 feet 75 C. B. Godfrey, sec. 15, altitude 880 feet 72 G.H.Brown, sec. 22, altitude 875 feet 64 D. AV. Pierce, sec. 27, altitude 875 feet 70 E. E. Barry, see. 27, altitude 865 feet 56 S. R. Ellithorp, sec. 27, altitude 875 feet 86 A well at John McDonough's, in sec. 26 of this townshij), 125 feet in depth, strikes an old soil at 40 feet. This soil is probably referable to the Peorian or post-Iowan interglacial stage. The altitude is not greatly different from that of the flowing wells, yet a flow was not obtained. A well at the mill in the village of Burhngton, 165 feet in depth, is in rock a few feet. A well at a hotel in the village reaches a deptli of 100 feet and obtains water in gravel below blue till. In the vicinity of Burlington several wells exceed 100 feet in depth. One in sec. 5 is 114 feet and another 99 feet. One in sec. 17 is 117 feet in depth. ' Part II, p. 827. WELLS OF KANE COUNTY, ILLINOIS. 597 In the vicinity of Richardson several wells have been sunk to depths of 80 to 120 feet, mainly throug-h till, and obtain water in sand and gravel without entering- rock. Mr. Richardson has two wells, one 84 feet, the other 87 feet; Mr. Dayton, one well, 117 feet; Mr. Frank Paul a well 120 feet. Other deep wells in that township range from 50 to 100 feet or more, with an average about 75 feet. Such wells are much stronger than those obtained at shallow depths. In T. 40, R. 7 E., there is an elevated morainic belt in which the drift probably averages over 200 feet. Each of the wells which enter rock pene- trate more than 200 feet of di'ift, and one well reaches a depth of 336 feet without striking- rock. In several wells an old soil is found at the depth of about 200 feet, which in some instances is probably between the lowan and Illinoian drift or the Sangamon interglacial stag'e. The following wells serve to illustrate the above statement. At J. Powell's, in sec. 7, altitude about 950 feet, buried soil is struck at 195 to 200 feet and rock is entered at 250 feet. The well is continued about 200 feet into the rock. At M. W. Powell's, in sec. 8, on_ nearly as elevated a point as the preceding, a well about 500 feet in depth penetrates 234 feet of drift. At a cheese factory in section 19, at an elevation of 950 feet, is a well 336 feet in depth which did not reach rock. An old soil is found below the blue till at 198 to 200 feet, with a greenish subsoil beneath it. A hard till of light gray color sets in at 240 feet and extends to the bottom of the well. Mr. Beith, in sec. 28, has a well 228 feet in depth, which is thought to strike rock at the bottom. The altitude is probably 925 feet. Mr. L. R. Read, in sec. 32, has a well 226 feet in depth, which passed through an old soil at about 180 feet and entered rock at 214 feet. The altitude of the well is about 925 feet. In the \dcinity of St. Charles in T. 40, R. 8 E., several wells have been sunk to a depth of 75 feet or more. One in sec. 1 strikes a black soil below blue till at a depth of 72 to 74 feet, and one on Mr. Dunham's farm, in the east part of the township, passes through a buried soil at 75 to 78 feet. The altitude at these wells is about 750 feet, or nearly 200 feet below that of the deep wells in the township on the west just noted. At Greneva a well at the court-house was sunk to a depth of 2,500 feet, and the Glucose Company have a well 2,000 feet in depth ; this company also has a well 400 feet in depth. No further data concerning these wells have been obtained. The village stands on a gravelly plain at a level 598 THE ILLINOIS GLACIAL LOBE. about 40 feet above Fox River. Wells are usually obtained without sink- ing- below tlie river level. In the A-icinity of this -^-illage rock is often encountered at depths of but 15 or 20 feet. The di-ift contiiuies thin south- ward past Batavia, and many wells in that ^^llag■e enter the rock. Upon passing westward from Fox River the drift increases markedly in thickness witliin the township limits, though the elevation remains about the same. Several instances of the occun-ence of a buried soil were found in this townsliip and the one adjoining it on the west. The following represent the deepest wells in T. 39, R. 8 E., of which sections were obtained; they are all at an altitude of about 750 feet: Wells near Batavia, Illinois. In sec. 4, old soil at 120 to 126 feet, gravel at bottom. East part of Batavia on liluff, rock at 60 feet. Sec. 2i, good -n-ells at 72, 81, and 112 feet in drift. Mr. Carr, sec. 20, well strikes rock at 43 feet. Jlr. Davenport, sec. 19, three wells in drift at about 100 feet. Daniel Frydendall, sec. 31, old soil at 80 feet; depth of well 90 feet. In T. 39, R. 7 E., wells are usually obtained at 40 to 75 feet, but a few exceed 100 feet. The following embrace the deepest of which sections wei-e obtained: Wells in T. 39, B. 7 E. Cheese factory at La Fox; depth, 126 feet; rock at 65 feet. C. G. Morse, sec. 3; depth, 83 feet; no rock struck; lower half a harder till than the upper. Mr. Outhouse's well, north of Elbum; altitude, about 900 feet; depth, 100 feet. Tile factory well at Elburn; altitude, 850 feet; depth, 70 feet; old soil at 60 feet. C. F. Field, sec. 10; altitude, 800 feet; depth, 96 feet; rock at 85 feet. P. Washburn, sec. 14 ; altitude, 825 feet ; depth, 169 feet. The well is on a gravel knoll 50 feet in height and penetrates: Gravel and sand, 50 feet; brown till. 97 feet; black muck, with log embedded, 2i feet ; yellow till, 7 feet; sand and gravel, with water, 10 feet. Mr. Sheets, sec. 20 ; altitude, 750 feet ; depth, 47 feet ; soil, with wood, at 40 feet. Blackberry P. O., sec. 21 ; well from gravel below till at 70 feet. F. S. Morrill, sec. 21; altitude, 750 feet; depth, 60 feet; mainly blue till. Mr. Kigling. sec. 22; altitude, 750 feet; depth, 50 feet; rock at bottom. D. C.Greene, sec. 22; altitude, 750 feet; depth, 40 feet; wood near bottom. Johnson's Mound, sec. 15; .altitude, 800 feet; depth, 180 feet. The well is on the slope of a knoll 80 feet above bordering plain. Another well passed through a bed of leaves and muck at about the level of the base of the mound. Neither well entered rock. William Beler, sec. 17; altitude, 750 feet; depth, 46 feet; rock at bottom. Annis estate, sec. 29; altitude, 700 feet; depth, 66 feet; mainly blue till; wood and black nnick at 64 feet. Well is thought to have struck rock at bottom. Russell Benton, sec. 30; altitude, 700 feet: depth, 75 feet; entirely in gravel. In the vicinity of Kaneville, as noted above, there is a delta-shaped jjlain of gravel formed at the western end of an esker (see PI. XR^). Near the western border the gravel is but 20 feet in depth, but at the eastern border, near the esker, wells 60 feet in depth do not reach the bottom. At WELLS OP KANE COUNTY, ILLINOIS. 599 Kaneville wells liave a depth of 35 or 40 feet and penetrate both gravel and till. At Charles Benton's, east of Kaneville, in sec. 25, a well 54 feet in depth is thonght to have struck rock. It penetrates clay 25 feet, sand 25 feet, gravel 4 feet. Near the center of the township, in sec. 15, a well on a knoll is entirely in gravel to a depth of 44 feet. In Sugar Grove Township the thickness of drift varies from 16 feet or less up to fuU}^ 75 feet. In the village of Sugar Grove the deepest wells are 50 to 70 feet without entering rock. In some instances they are through gravel and in others mainly through till. A well at Mr. Hatch's, in sec. 7, 70 feet in depth, obtains water in gravel at bottom and penetrates alterna- tions of clay and fine sand. Mr. Dorr, in sec. 8, has a well in a basin at the side of an esker which is entirely in clay to a depth of 20 feet. On the borders of the basin the drift is gravelly, like that of the esker. Mr. S. E. Sheppardson, in sec. 16, has a well 75 feet in depth, which is entirely through sand and cemented gravel. Mr. Chapman, near Sugar Grove, has a well 90 feet in depth, which entered rock at 60 feet. It was mainly through till. Mr. Potter, in sec. 32, has a well on a knoll, which reaches a depth of 70 feet without entering rock. The upper 40 feet is gravel and sand; the remainder is sandy till. At Aurora the public water supply is from a series of deep artesian wells 1,388, 2,270, and 2,255 feet in depth. The first obtains water from the St. Peter and the others from the Potsdam sandstone. The water has a head about 60 feet above the surface, or 710 feet above tide. An analysis of the water from each well appears in the Seventeenth Annual Report of this Survey.^ The water from the St. Peter sandstone contains a remarka- bly small amount of saline matter and is of excellent quality for domestic use. The Potsdam water is more saline than the water from the St. Peter sandstone. Private wells are obtained in Aurora and vicinity at about 40 feet in gravel. Rock is extensively exposed along Fox River in the city and below as far as the county limits. DEKALB COUNTY. GENERAL STATEMENT. Dekalb County is situated immediately west of Kane and near the middle of the second tier of counties from the north. It has an area of 650 square miles, and Sycamore is the county seat. The greater portion of I Part ir, p. 820. 600 ^ THE ILLINOIS GLACIAL LOBE. the county drains northward through the south fork of Kishwaukee River. The southeastern jjart is tributary- to Fox River. Like the counties to the east, it is so imperfectly drained that much artificial drainage has been made, both by surface ditches and by tiling. The Bloomington morainic system which crosses the central portion in a northeast-southwest direction rises about 100 feet above the district on the outer border. There is on the imier border a gTadual descent to the valley of Fox River across a plain dotted with only occasional knolls. The di-ift is probably as heavy as in any of the counties of northern Illinois (except perhaps Bureau County), there being in 22 borings which reach rock an average thickness of 151 feet, while 68 other deep wells which do not reach rock show an average of 101 feet. The jaortion on the north border of the county outside the morainic system has scarcely 50 feet of drift, and as it comprises an area of fully 100 square miles it materiallv reduces the average for the county. As in the counties to the east, the drift is largely a blue till, and occasional instances of the occurrence of a buried soil near or perhaps below the level of the base of the Wisconsin di'ift have come to notice. In a large part of the county dairying is the principal pm-suit, and many deep wells have been sunk to supply the stock or to furnish water for the creameries and cheese factories. Many of these wells exceed 100 feet in depth, and wells 200 feet or more in depth are not I'are. INDIVIDUAL ATELLS. In the northwest townsliip of the county there are few deep wells, water usually being obtained at 25 to 40 feet. A well in sec. 36, however, reached a depth of 75 feet without entering rock. At several points within the township the rock outcrops at a level not more than 25 feet below this well mouth, or about 800 feet above tide. A flowing well in sec. 35 is sup- jjlied from gi-avel below till at a depth of 22 feet. In T. 42, R. 4 E., rock outcrops are nearly continuous along the Kish- waukee Bluft's up to an altitude about 750 feet above tide. A few wells in the vicinity of the river penetrate 40 feet or more of drift. On the south border of the township there is a rise of 100 feet or more to the niorainic system refen-ed to above, and wells here exceed 100 feet in depth without reaching rock. One at Mr. Leander Roberts's, in sec. 32, has a depth of 132 WELLS OF DEKALB COUNTY, ILLmOIS. 601 feet. Another in the same section, at Mr. Keague's, has a depth of 110 feet. At Genoa, in the northeast township of the comity, the wells are 25 to 60 feet in depth and obtain their supply from gravel below till. A well in sec. 26, near New Lebanon, at an altitude about 850 feet above tide enters rock at 90 feet, and has a depth of 122 feet. The south border of this township is occupied by the outer moraine of the Wisconsin drift, but no records of deep wells were obtained. In the township to the south, however, records of several wells were obtained which show the di'ift to reach a thickness of 150 to 200 feet or more. For example, in sec. 9., T. 41, R. 5 E., a well 156 feet in depth does not reach rock and is mainly through blue till. The altitude is about 900 feet. At Mr. Marshall's, in sec. 11, at a similar altitude, a well has a depth of 111 feet. At John Haine's, in sec. 2, a well is obtained at 86 feet. Near the center of the township, in sec. 15, Mr: E. Devine made three unsuccessful borings for water to a depth of about 200 feet without reaching. the bottom of the drift. The altitude at the wells is about 875 feet. Four wells in sec. 25 each have a depth of about 125 feet, and a fifth well has a depth of 170 feet. They are all mainly through blue till, and none enter the rock. In sees. 35 and 36 three wells have a depth of about 100 feet, a fourth has a depth of 148 feet, and a fifth a depth of 151 feet, all mainly tlu'ough blue till. In T. 41, R. 4 E., records of wells show the depth of dt-ift to exceed 100 feet, while one well in sec. 31 reaches a depth of 113 feet without reaching rock. This well is thought to have passed through an old soil at about 80 feet. Another well in the same section has a depth of 112 feet. The wells of this township are mainly through blue till, but one, in sec. 11, is reported to have passed tlnough 35 feet of yellow till and 10 feet of sand before entering blue till. The well has a depth of 98 feet, and terminates in a cemented gravel. A portion of township 41, R. 3 E., is outside the above-mentioned morainic system and wells there are seldom more than 80 feet in depth. A well at Dustin post-office, 77 feet in depth, is reported to have struck rock near the bottom. Another, in sec. 8, 76 feet in depth, penetrates about 2 feet of rock at bottom. At a schoolhouse in this section, however, a well strikes rock at 12 feet. The altitude at each of these wells is about 825 feet 602 THE ILLINOIS GLACIAL LOBE. above tide. At Deerfield post-office an old soil was found beneath the blue till at a depth of 35 or 40 feet. As this stands outside the Wisconsin drift sheet, the soil is to be refen-ed to an earlier interg-lacial stage than that immediately preceding the Wisconsin stage of glaciation, probably the Sangamon stage. A well on the moraine in sec. 27, about 75 feet higher than Deei-field, enters a black soil at a depth of 125 to 130 feet, or at nearly the same level as that at Deei'field, and perhaps to be refen-ed also to the Sangamon interglacial stage. The following records of deep wells were obtained along the moraine in the southeast part of this township: Wells in T. 41, B. 3 E. Feet. Mr. Casey, sec. 13, altitude 87.5 feet 130 John Lloyd, sec. 27, altitude TOO feet 130 Sergis Lloyd, sec. 34, altitude 900 feet 190 James Gibson, sec. 23, altitude 850 feet .♦. 90 James Renwick, sec. 28, altitude 900 feet, enters rock at 230 feet 230 In T. 40, R. 3 E., a well in sec. 3, 183 feet in depth, enters rock at 176 feet. The altitude of the well mouth is about 900 feet. A well in sec. 20, 109 feet in depth, is reported to have passed tlu-ough a black soil near the bottom. The altitude is about 875 feet. A well a mile east from this reached a depth of 123 feet. In T. 40, R. 4 E., records of several wells which reach rock were obtained. One at Mr. Barlow's, in sec. 31, 153 feet in depth, enters rock at 140 feet. One at Mi*. Gui-ler's, in sec. 32, also enters rock at about 140 feet. The altitude at these wells is 860 to 875 feet. A well at William Barr's, in sec. 31, at similar altitude, failed to reach rock at 183 feet. At Dekalb one of the artesian wells reaches rock at 126 feet, another at 195 feet, and another at 309 feet. South of Dekalb, in sec. 33, a well enters rock at 225 feet. The altitude of these wells in the vicinity of Dekalb is between 865 and 900 feet. Records were obtained of seven wells between Dekalb and Malta having a depth of about 100 feet each, and one well having a depth of 150 feet, none of which enter rock. The city water supply of Dekalb is obtained from a well 890 feet in depth, wliich terminates in the St. Peter sandstone. Several other deep wells have been made in the city wliicli terminate in that sandstone. A well at the public square was drilled to a depth of 2,470 feet and terminated in the Potsdam sandstone. Mr. Elwood sunk a well neai* Dekalb to a depth of 700 feet. None of the wells mentioned overflow. The well at WELLS OF DEKALB COUNTY, ILLmOIS. 603 the city waterworks stands about 65 feet below the surface. It is prob- able that all obtain water from horizons above the St. Peter as well as from that sandstone. The well at the public square penetrated till 145 feet, below which there was 50 feet of sand and gravel. The well in sec. 33, noted above, penetrated a till, mainly of bluish color, 145 feet; sand, 20 feet; blue till, 59 feet. Mr. El wood's well had about 100 feet of till at surface; the remaining 200 feet was mainly sand and gravel. The city water supply at Sycamore is obtained from several flowing wells, which obtain water at a depth of about 65 feet, from gravel beds below blue till. There are several other flowing wells of similar depth along the Kishwaukee River Valley in the vicinity of Sycamore. Wells are usu- ally obtained in this township at depths of 50 to 85 feet, there being appar- ently a sheet of gravel and sand below blue till at this honzon. In the western part of Dekalb County, in T. 39, Rs. 3 and 4 E., several wells have been sunk to the rock, as follows: Wells in western JDelcalb County that reach rock. Locality. Altitude. Depth. Feet. Feet. 875 224 900 170 900 260 925 228 925 200 890 162 925 175 925 199 860 140 In sec. 1, T. 39, K. 3 E Wm. Keast, sec. 4, K. 3 E Holton Brue, sec. 11, R. 3 E Theodore Burgh, sec. 19, K. 3 E . . . Theodore Burgh, sec. 19, E. 3 E . . , John Watson, sec. 28, R. 3 E , A. W. Howard, sec. 20, R. 3 E Andrew Nicholson, sec. 20, R. 3 E H. Gerler, sec. 5, T. 39, R. 4 E All these wells, with the exception of Mr. Nicholson's, terminated after penetrating rock less than 10 feet. But Mr. Nicholson's had penetrated 25 feet of rock at the depth above given. A boring in sec. 7, T. 39, R. 3 E., at an altitude about 925 feet, reached a depth of 230 feet without entering rock or obtaining water. Another boring on the same farm obtained water in gravel at a depth of 192 feet. A well in sec. 9 obtained water in gravel at a depth of 172 feet. In T. 38, R. 3 E., a well in sec. 8 strikes rock at 152 feet, though located on an elevated jDart of the moraine nearly 950 feet above tide. Several other tubular wells in that vicinity reach rock at depths of less 604 THE ILLINOIS GLACIAL LOBE. than 200 feet, but one well reached a depth of 212 feet without encoun- teiing rock. Two wells in the west pai-t of the township, on the farms of Taylor Thompson and William Storey, at altitudes about 9.50 feet, struck an inflammable gas in gravel at depths of 125 to 150 feet. The drift is mainly till above this gravel. Strong wells are obtained from gravel in that vicinity at 100 to 150 feet. On the plain in the southeast part of the county wells are usually obtained at depths of 30 or 40 feet. The railroad well at Hinckley, how- ever, was sunk to a depth of 190 feet and entered rock at about 100 feet. The altitude is 750 feet at this well. At Sandwich, where the altitude is only 655 feet, the wells for the public water supply are sunk to a depth of 113 feet without entering rock. Several tubular wells are driven in the bottom of a large well. Private wells in Sandwich and vicinity usually obtain an abundant supply at about 30 feet. In the southwest part of the county several flowing wells have been obtained from the drift at depths of less than 30 feet. Ten such wells have been made on sec. 32, T. 37, R. 3 E., whose depths are but 22 to 27 feet. A well in sec. 31 is 24 feet. The altitude at these wells is about 725 feet above tide. This flowing well district extends southward to Earlville in Lasalle County. The absorption area is probably from the moraine on the northwest. A well in sec. 2, T. 37, R. 3 E., 67 feet in depth, passed throus'h an old soil at 55 to 60 feet. The altitude at the well is about 800 feet. OGLE COUNTY. GENERAL STATEMENT. Ogle County is situated west of the northern part of Dekalb County, and south of Winnebago and Stephenson counties. It has an area of 780 square miles, and Oregon is the county seat. Rock River traverses the county nearly centrally in a course west of south, and the county is drained by small tributaries of that stream. The greater part of the county is covered but thinly with drift, and preglacial ridges and valleys are in many cases readily traced. The outer moraine of the Wisconsin drift touches the southeast corner of the county, and the drift there is 250 feet or more in thickness. The large jjreglacial ^■alle3•, thought to be the old course of Rock River, traverses the eastern part of the county in a north to south WELLS OF OGLE COUNTY, ILLINOIS. 605 direction. It is filled nearly to the level of the bluffs, and judging by the distance to rock in portions of the valley to the north and south, thei-e is probably not less than 400 feet of drift filling. Along the present course of Eock River there are continuous bluffs rising to heights varying from 75 up to fully 200 feet. On the uplands, in fully three-fourths of the countj^, wells commonly enter the rock at 10 to 40 feet, and obtain water at depths ranging from 50 feet up to about 300 feet. Along the lines of preglacial valleys water is usually obtained at a shallow depth in gravel. There are belts of gravelly drift of esker type in the western part of this county similar to those in Stephenson County on the north, and with a similar east to west trend. Aside from these gravelly strips the drift is usuall}^ a compact till. There are,- however, as in Stephenson and Winnebago counties, many places where it is made up largely of coarse stony material. In the portion outside the Wisconsin drift there are two drift sheets of widely different age. The later of these, the lowan, appears to extend but little west of Eock Eiver, thus leaving only the lUinoian, in the western part of the county, unless a sheet older than Illinoian is found to be present. INDIVIDUAL WELLS. In the northwest part of the county, in the vicinity of Foreston, a till sheet 30 to 40 feet in thickness is generally present. Some of the wells are obtained without entering the rock, but the stronger wells are usually drilled into the limestone. The public water supply at Foreston is obtained from a well 300 feet in depth, in which water rises within 20 feet of the surface. The private wells are 35 to 80 feet in depth. At Mount Morris the public supply is from a well 502 feet in depth, whose head is nearly 200 feet below the surface and near the top of the St. Peter sandstone. At Adeline the drift is gravelly, the village being situated on a plexus of knolls and ridges associated with an esker which leads westward along Leaf Eiver. Wells here obtain water at depths of 30 to 75 feet in gravel. At Hazelhurst, on the west border of the county, there is an esker in which a well was sunk to a depth of 135 feet before striking rock, though the well mouth is 50 feet below the highest part of the esker. Between 606 THE ILLINOIS GLACIAL LOBE. Hazellmrst and Polo rock is usualh- entered at 2U feet or less and the drift is of ^•ariable constitution, there being abrupt changes from gravel or sand to till. There is a general capping of loess in that vicinity 6 or 7 feet in depth. The public water supply at Polo is obtained from a well 2,100 feet in depth, which terminates in the Potsdam sandstone. It is situated in a creek valley, and has but 37 feet of drift. The water is of pleasant taste and is obtained in sufficient quantity for the needs of the town. A well at French's tile yard at Polo penetrates about 80 feet of drift. The upper 13 feet is loess and sandy material, but the remainder is a compact till. East of Polo, on the divide between Elkhorn and Pine creeks, there are several wells which penetrate about 60 feet of di-ift. The}" are in a blue till from 20 feet downward to the rock. At Stratford the village well is 45 feet in depth without entering rock. The railway cuttings immediately east of this village expose two sheets of till separated b}' a fossiliferous silt. The upper sheet as stated above (p. 138) is apparentl}" much younger than the lower and is probabl}" of lowan age. Within a mile east of Stratford rock ledofes occur at an elevation as hig-h as the railway station (820 feet). At Oregon the wells range in depth from 20 to fully 200 feet, but are usually about 30 feet. The public water supply was pumped from Eock River until recently, but the Manual of American Waterworks (1897) reports the. present supply to be from wells. A railway cutting- between Oregon and Mount Morris exposes a buried soil below till at a depth of about 25 feet. This probably separates the lowan from the lUinoian till sheet. At the village of Grand Detom* wells on a terrace in the ^'allev of Rock River obtain water in g-ravel at a depth of 20 feet. At the village of Byron, which is situated on a terrace standing about 50 to 55 feet above Rock River, wells are usually sunk through a gravelly sand to the level of the ri^-er. In the vicinity of Stilhuan Valley the drift is gravelly, and wells are usually obtained at a depth of 25 feet or less. On the uplands bordering the valley in which this village is situated rock is usually struck at a depth of 10 or 15 feet. WELLS OF OGLE COUNTS, ILLINOIS. 607 At Davis Junction a town well 53 feet in depth enters rock at 18 feet, and the rock outcrops in many places toward the south. West and north from Davis Junction wells usually penetrate 50 to 80 feet of drift. A well made by F. H. Baker, 1^ miles west of Davis Junction, is 190 feet in depth and strikes rock at about 80 feet. Northeast and east from this village wells reach a depth of over 100 feet without entering rock, this being the position of the old valley of Rock River referred to above. The deepest well noted is at Mr. Kerr's, in sec. 11, which obtains water from gravel at a depth of 120 feet. There appears to be a' heavy sheet of till along this preglacial valley, wells 80 to 120 feet in depth being mainly tln-ough that deposit. At Monroe, which is situated on the east side of the old Rock River Valley, rock is usually struck at 5 or 10 feet, but Mr. Tyler's well pene- trated 44 feet of di-ift before entering' rock. The railway cutting immediately west of Monroe also exposes drift to a depth of over 30 feet. Records of sevei'al wells were obtained in sees. 27, 28, 29, 30, 31, 32, 33, and 34, T. 42, R. 2 E., which are about 30 feet in depth, and but one well enters rock. East from these sections as far as the county line rock is usually entered at a depth of 10 to 20 feet. Two wells in sec. 2, T. 41, R. 2 E., enter an old soil below till at a depth of 20 to 22 feet, which is thought to separate the lowan sheet from an underlying older one. This soil in all probability represents, the Sanga- mon interglacial stage. About 2 miles south from these wells, at James Ashbrook's, a black muck was struck at 67 feet, which yields an inflammable gas. The altitude at each of these wells is about 780 feet above tide and the biu-ied soils are probably all referable to the same stage. In the vicinity of Lindenwood rock is struck at slight depth (12 to 25 feet). The preglacial valley of Rock River appears to lie entirely, north and east of this village. A well at William Stocking's, near this village, in sec. 1, T. 41, R. 1 E., reached a depth of 100 feet without entering rock. It is probably over the line of a tributary of the Rock River Valley, for neisrhborino- wells enter rock at 12 to 30 feet. In the vicinity of Kings Station, and thence . westward past Paines Point, wells usually enter rock at about 10 feet and obtain water at 30 to 50 feet. At Rochelle the public water supply is obtained from springs issuing from an old rock quarry. Wells are usually obtained at 30 or 40 feet and 608 THE ILLIISrOIS GLACIAL LOBE. enter limestone at about 10 feet. The old valley of Rock River passes east of tliis city. At Creston, which is situated on the outer moraine of the Wisconsin drift, a well at the tile factory, 256 feet in depth, enters rock at 250 feet. Several other wells in this village and vicinity are 150 feet, but probably the majorit}" of wells average not more than 50 feet. They are mainly through a soft blue till. LEE COUNTY. GENERAL STATEMENT. Lee County is situated south of Ogle and west of the southern portion of Dekalb. It has an area of 740 square miles, and Dixon is the county seat. Rock River crosses the northwest corner, but drains by direct tribu- taries only a small portion of the county. The central and southwestern portions drain into Green River, the main southern tributary of Rock River. The southeastern portion of the county is drained by Bureau Creek, a tributary of the Illinois. The portion drained by Green River is largely a marsh, but artificial drainage has brought much of it under cultivation. The outer morainic system of the Wisconsin drift occupies the eastern and southern borders of the county, and stands 100 to 150 feet or more above the neighboring portions of the Green River marsh on its outer border. The preglacial Rock River apparently passed tln-ough this portion of the county. It is probable that where the elevated portions of the moraine coincide with this old valley there is not less than 600 feet of drift, the rock floor of the old valley being known to be at a level that much Ijelow the crest of the moraine. Northwestward from the Green River marsh the drift is generally of slight depth, many wells entering rock at 25 feet or less, while outcrops of the limestone are common on nearly all the streams in that part of the county. Wells are usually obtained at moderate depths in the rock, seldom more than 50 feet. On the moraine in the eastern and southern portion of the county the wells in several instances exceed 200 feet in depth without entering rock, and in portions of the Green River marsh the drift is known to exceed 200 feet. The usual depth of wells on the moraine is, however, not more than 100 feet, there being considerable sand and gravel associated with the till which forms the body of the drift. WELLS OF LEE COUNTY, ILLINOIS. 609 INDIVIDTIAL WELLS. At Dixon the public water supply is obtained from three artesian wells, 1,637, 1,710, and 1,810 feet in depth, which terminate in the Potsdam sandstone. The wells overflow into a reservoir, from which the water is pumped to a standpipe. An analysis of the water, published in the Seven- teenth Annual Report of this Survey,^ shows a very small amount of salt and a moderate degree of hardness. The water is considered of pleasant taste and excellent quality. The wells are cased only about 50 feet. The water in each well has a temperature 55° F. At Nachusa wells are usually obtained at about 30 feet without entering rock. A well one mile northwest of the village reached a depth of 95 feet without striking rock. Within a half mile of this well, however, rock outcrops at a higher elevation than the well mouth. At Franklin Grove, and also at Ashton, wells usually enter rock at 30 or 40 feet, and there are numerous outcrops of rock in that vicinity. In several instances coal has been found in the drift in the vicinity of Ashton. As this point is north of the border of the coal field, it suggests a noi'thwestward movement of the ice in this region, though the occurrence of coal here may perhaps be due to the presence of outliers north of the main coal field. As indicated below, coal apparently underlies the southeast corner of this county. The drift is thin over the southern half of T. 39, R. 1 E., and northern half of T. 38, R. 1 E., but north and east from this locality wells occasion- ally reach depths of 50 and even 100 feet without entering rock. The deepest section of such a well, noted in T. 39, is that of Robert Peile, in sec. 23, which reached a depth of 108 feet. The well has the following section : Section of Peile well in T. 39, R. 1 E. Feet. Soil and brown till 10 Gravel 1 Blue till 20 Gravel 5 Brownish till, with occasional gravellj' beds 72 The upper 36 feet of this section should perhaps be referred to the lowan stage of glaciation. Blue till is occasionally entered in that vicinity at only 6 or 7 feet below the surface, or at a much shallower depth than in the drift of the Illinoian stage. I Part II, p. 827. MON XXXVIII 39 610 THE ILLINOIS GLACIAL LOBE. At Amboy shallow wells are obtained at 12 to 20 feet, many of which enter the rock. At the waterworks the supply is obtained from an artesian well 2,000 feet in depth. Water veins which ovei-flow were struck at 390, 1,100, and 1,700 feet. The lower veins do not increase the head, but evi- dently increase the quantity, for the upper flows could be readily lowered by pumping, while the lower ones can not. The discussion of wells on the moraine which •follows begins in the northeast jjart of the county, from which point the moraine is followed southwestward. Table of deep wells in eastern and southern Lee County, Illinois. Location. Sec. 3, T. 39, R. 2 E Sec. 34, T. 39, K. 2 E Sec. 32, T. 39, R. 2 E Sec. 15, T. 38, R. 2 E Sec. 12, T. 38, R. 2 E Sec. 16, T. 38, R. 2 E Sec. 14, T. 38, R. 2 E Sec. 36, T. 38, R. 2 E Sec. 33, T. 38, R. 1 E Sec. 18, T. 37, R. 2 E 3 miles S. of Pawpaw . . . Sec. 36, T. 37, R. 2 E Sec. 35, T. 37, R. 2 E Sec. 19, T. 37, R. 2 E Sec. 32, T. 37, R. 2 E . . . . Sec. 30. T. 38, R. 1 E . . . . Sec. 29, T. 38, R. 1 E . . . . Sec. 12, T. 19, R. HE ... Sec.2,T. 19,R.8E Sec. 36, T. 19, R. 8 E . . . . Sec. 14, T. 20, R. 8 E .... Sec. 28, T. 20, R. 8 E .... Altitude ; r,„„*v (above tide).! ^'^P*''- Feet. 800 775 950 t. Feet. 925 168 925 200 875 45 950 200 950 50 875 40 875 60 950 217 820 114 800 115 800 100 Remarks 155 100 287 925 200 800 84 800 90 935 218 660 200 800 200 700 105 690 166 In gravel below till. Old soil at 100 feet ; no rock struck. Gravel below till. Gravel below till. Gravel below till. Entirely in gravel. Mainly sandy drift. In gravel belovr till; no rock. No rock ; old soil at 80 feet. Driller reports coal at bottom. Driller reports buried soil at 80 feet, sandstone at 90 feet, and coal at about 100 feet. Old soil at 78 to 81 feet; drift mainly till; no rock struck. Mainly sand and gravel ; no rock. Old well, 45 feet; sand, 5 feet; blue till, 190 feet; greenish clay, 19 feet; rock (?), 6 feet; blue till, 15 feet; cemented gravel, li feet; loose gravel at bottom. Not known whether rock was struck. Soil and wood near bottom. Wood ami leaves at bottom. Little, if any, rock penetrated. No rook struck. Terminates in sand. Wood, with inflamniablo gas, at 110 feet. No rock; beds of sand and gravel in blue till. No rock struck; sand, 25 feet; remainder blue till. WELLS OF CARROLL COUKTY, ILLINOIS, 611 The last edition of the Manual of American Waterworks (1897) reports that the village of Pawpaw, in the southeast part of the county, obtains its public supply from an artesian well 1,018 feet in depth. CARROLL COUNTY. GENERAL STATEMENT. Carroll County borders the Mississippi River in the second tier of counties from the north and has an area of 440 square miles, with Mount Carroll as the county seat. The northwestern portion is drained by Plum River and Carroll Creek, its main tributary, directly to the Mississippi Valley at Savanna. The southeastern portion is di-ained southward through Rock and Elkhorn creeks into Rock River. The surface is rolling and drainage good throughout the upland portion of the county. With the exception of the northwest corner, which is ung-laciated, this county is covered with a sheet of drift of moderate depth. Records of 14 wells on the uplands, distributed widely over the county, show an averag-e of 54 feet to the rock, the greatest depth being about 100 feet. In the Mississippi Valley below Savanna there is probably 150 feet or more of drift, as indicated by borings at Sabula, Iowa, and Fulton, Illinois, which reach a level nearly 150 feet below the Mississippi before entering rock. The valley di-ift is lai'gely sand or fine gi-avel. The drift on the uplands is in places a gravelly or stony material, but usually has a large clay admix- ture, such as characterizes the typical till. In every township of the uplands numerous wells enter the rock, but a still larger number obtain water from gravel or sand associated with till at various depths from 20 feet or less up to about 100 feet. INDIVIDUAL WELLS. At Savanna the public water supply is from an artesian well 1,430 feet in depth, which terminates in the Potsdam sandstone. It discharges at the rate of 500 gallons per minute and has a pressure of 35 pounds per square inch at the level of the well mouth, about 600 feet above tide. The head is, therefore, about 675 feet. At Mount Carroll the public water supply is from a well 2,502 feet in depth, which has a head sufficient to rise nearly to the well mouth, about 700 feet above tide. Water was struck in the limestone at 65 to 100 612 THE ILLINOIS GLACIAL LOBE. feet, but a much stronger supply was struck at about 1,200 feet. The drift is largely gravel aud has a depth of 61 feet The well is situated in a valley about 100 feet below the bordering uplands, and rock appears in the uplands near by at a level fully 50 feet above the well mouth. A well at the railway station in Mount CaiToll reaches rock at a depth of 60 feet. The altitude there is 816 feet above tide. This well penetrated a complex series of beds of gravel, sand, and till. A boring at William Petty's, 4 miles southwest of Mount Carroll, is reported to have penetrated about 300 feet of drift. On the farm of R. Hostetter, 3 miles southeast of Mount CaiToll, a well strikes rock at the depth of 72 feet; the drift is mainly a blue clay. Hon. James Shaw reports a well section near Mount Carroll, which sti'uck a black mucky clay, apparently a soil, at a depth of about 50 feet; another well at the farm of F. O'Neal, 3 miles from Mount Can-oil, passed through a soil and wood at 15 to 20 feet. The latter is perhajDS at the junction of the loess with the underlying- glacial di'ift, but the former penetrated a sheet of glacial di'ift above the soil, and its section is as follows : ^ Section of a well near Mount Carroll, Illinois. Feet. Soil, yellow and blue clays 15 Eeddish clay and gravel 15 Tough blue clay 2 Coarse gravel •- 3 Yellow sand 11 Black mucky clay 5 A deep artesian well has been sunk in a creek valley about 4 miles south of Mount Carroll, which overflows with considerable force. No further data have been olitained. At Lanark the public water supply is from a well obtained near the top of the limestone at about 100 feet. The following drift beds were penetrated: Clay, 12 or 15 feet; gravel and sand, 12 or 15 feet; blue clay, with few pebbles, 75 feet. A well at L. Sprecher's, 1 mile west of Lanark, enters rock at about 100 feet and there obtains water. In the township east of Lanark wells are reported to differ greatl}^ within short distances in the amount of drift penetrated, some entering rock at about 20 feet while others penetrate 100 feet or more of drift. ' Geology of lUinois, Vol. V, p. 80. WELLS OF CARROLL COUNTY, ILLIN31S. 613 At Shannon wells near the railway station enter rock at 15 or 20 feet, but on a rock ridge in the sonth part of the village, at an elevation proba- bly 30 feet higher than the railway station, or 950 feet above tide, rock is entered at 8 or 10 feet. The public water supply is reported by Manual of American Waterworks (1897) to be from a drilled well. In the south part of the county, in the vicinity of Ideal, several wells enter rock at 30 or 40 foot. The loess in that locality is about 15 feet in thickness. At Argo, in Johnson Creek Valley, 125 feet of sand and gravel were penetrated before striking' rock. At Fair Haven (altitude about 875 feet) the creamery well has the following section, furnished by the driller, Mr. J. Schlemming, of Chad wick: Section of well at Fair Haven, Carroll County, Illinois. Feet. Drift 40 Niagara limestone and chert 60 Mainly shale 210 Gray limestone 15 Total 325 Mr. Schlemming states that the wells in the south part of Fair Haven Township often obtain water in the cherty beds above the shale ; otherwise they must be sunk to limestone beds beneath the shale. At Chadwick the public water supply is from a well 215 feet in depth, which enters rock at 59 feet. The rock is entirely a gray limestone and appears to be the same formation which was entered near the bottom of the Fair Haven well. The drift is mainly clay, there being "but little sand or gravel. The head is about 40 feet below the level of Chadwick railway station, or 735 feet above tide. The well has a diameter of 5| inches and is estimated to furnish 400 barrels per hour. In the vicinity of Milledge^dlle the best wells are about 180 feet in depth and are probably from Galena limestone. The town well has a depth of only 80 feet and enters Galena limestone at 12 feet. Many wells obtain weak veins of water at about 30 feet near the top of the limestone. 614 THE ILLINOIS GLACIAL LOBE. WHITESIDE COUNTY. GENERAL STATEMENT. Whiteside County borders the Mississippi River in the third tier of counties' from the north line ' of the State and has an area of 700 square miles, with Morrison as its county seat. Rock River leads through the county from the eastern border to the southwest comer and receives the drainage of the greater part of the county, only a narrow belt on the north- west being directly tributary to the Mississippi. The southern half of the county is a lowland tract standing but little above the level of Rock River, its general elevation being about 650 feet above tide. The northern and western portions have an altitude corresponding with that of the uplands in Carroll and Ogle counties, the altitude of a considerable part being above 800 feet and in places reaching nearly 900 feet. Two narrow low- land tracts, resembling river valleys, connect the Mississippi River with the lowland bordering Rock River, one of which, on the southwest border of the county, is known as Meredosia Slough, and one, leading from near Fulton to Fenton, as Cattail Slough (see PI. XVIII). These sloughs stand so little above the level of the Mississippi and Rock rivers that they are occupied in flood stages of either stream, and the direction of flow depends upon the stream which chances to have the higher stage. On the uplands the drift is of variable thickness, but is generally thinner in the northern and northeastern portions than in the western por- tion of the county. The general thickness, however, seldom falls below 50 feet even on ridges. In the western portion, from near Fulton south- ward past Garden Plain to Erie, there appears to be an average thickness of fully 150 feet. Were this drift removed, the elevation would differ but little from that of the lowland tracts bordering Rock River, for rock is often found at slight depth beneath these lowlands except in the southeast portion of the county. In the uplands of the northern portion of the county some wells are sunk to considerable depth in the rock. In the west- !, em portion they usually obtain water in the drift or at slight depth in the j,i rock. On the lowlands north of Rock River the wells are generally shal- ji low and often enter the rock a few feet. In the southeastern part of the county much of the land has not been brought under cultivation, the sur- WELLS OF WHITESIDE COUNTY, ILLINOIS. " 615 face being either sandy or marshy, and comparatively few deep wells have been sunk. Deep wells in the neighboring portions of Lee and Bureau counties penetrate over 200 feet of drift, and it is probable that a similar depth extends over three or four townships in the southeast part of this county. INDIVIDUAL WELLS. At Fulton, in the Mississippi Valley, in the northwest comer of the county, the city water suppl}^ is from an artesian well 1,246 feet in depth, which terminates in the Potsdam sandstone. A flow of sulphurous water was struck at about 475 feet. Another flow was obtained from the Potsdam at 940 to 1,050 feet. The head is sufficient to carry the water 60 feet above the surface, or about 655 feet above tide. The well has a diameter of 5 inches and an estimated capacity of 300 gallons per minute. The drift at this well is reported by the engineer of waterworks to be 125 feet, but Prof. J. A. Udden obtained a record which is thought to be more reliable in which the drift is rejDorted to be aboiit 200 feet. Shallow wells in the valley in the vicinity of Fulton are obtained at a depth of about 25 feet. Wells on an island-like upland in the north part of the city, standing 100 feet more or less above the river, are sunk to depths of 60 or 75 feet. They enter rock at the base of the loess at about 25 to 30 feet, thei-e being but little glacial drift. Near Ustick rock is usually entered on ridges at about 50 feet and in i places at much less depth, but occasionally a greater depth is found. A ' well on a ridge one-fourth mile south of Ustick did not reach rook at 200 feet. Farther east, in the elevated part of the county, wells enter rock at 50 to 75 feet and not infrequently reach depths of 100 to 150 feet or more. In the vicinity of Garden Plain, in T. 21, R. 3 E., wells enter a bed of jj black muck containing wood at a depth of 30 or 40 feet. The material above the muck is usually free from pebbles and is of the coarseness of sand rather than of loess. ' There appears to be no till or other strictly glacial material above the soil Beneath this muck a blue till is entered, which extends usually to the rock at a level 65 to 100 feet or more below the sur- face. East and south from Garden Plain the distance to the blue till varies from 25 feet or less up to about 50 feet. A well in sec. 24 enters blue till 616 THE ILLINOIS GLACIAL LOBE. at 25 feet and rock at 67 feet. A well in sec. 26 entered rock at 78 feet without jjenetrating any bine cla j, the following being its section : Section of a well near Garden Plain, Illinois. Feet. Loess 15 Fine sand 15 Coarse sand, becoming gravelly near bottom 48 Rock 5 A well in sec. 11, 106 feet in depth, enters rock at about 100 feet. Pro- fessor Udden reports that in sees. 1 and 2 of this township rock is stmck at a depth of only 30 feet. In the vicinity of Union Grove and thence east to Morrison the wells usually enter rock at less than 30 feet, but a well in sec. 18, 70 feet in depth, peueti-ates rock only 2 feet. It is entirely tln-ough sand, and is reported to have peneti'ated snail shells near the base of the sand. A well near the center of sec. 12 enters rock at 63 feet, and is reported to be entirely through loess and sand, except 3 feet of gravel at the top of the rock (Udden). The public water supply for the city of Momson is obtained from springs in Rock Creek Valley. An artesian well was sunk at this city to a depth of 1,190 feet. Mr. S. D. Gossert, editor of the Whiteside Sentinel, reports that the head is sufficient to carry the water 15 feet above the sur- face, but the well was not in use at the time his communication was received (August, 1895). Mr. Gossert reports that the wells in the ^dcinity of Mor- rison range from 35 to about 80 feet in depth, and are in nearly all cases obtained fi-om the rock. Southeast of Morrison, near the south border of the township, the present writer obtained records of several wells which do not enter rock at depths of 40 or 50 feet, but other wells in that vicinity enter rock at about 20 feet. Rock outcrops extensively in the vicinity of Rock Falls and Sterling. But a well in sec. 33 of this township is repoited by Professor Udden to penetrate drift 84 feet and to terminate in limestone at 313 feet. With the exception of 5 feet near the bottom of the drift, there was no clay in this well section, the greater part being sand and fine gravel. The public water supply at Sterling and also at Rock Falls is obtained fi'om an artesian well 1,450 feet in depth, which terminates in the Potsdam sandstone.^ The well ovei-flows at an elevation about 670 feet above tide 'The Manual of American Waterworks, 1897, reports a depth of 1,600 feet. WELLS OF WHITESIDE COUNTY, ILLINOIS. 617 and has an estimated capacity of 350 gallons per minute. An analysis is given in the Seventeenth Annual Report of this Survey/ which shows it to be a moderately hard water with veiy little salinity. Private wells in the vicinity of Sterling range in depth from 25 to 100 feet, with an average about 35 feet. Only the shallowest ones are obtained in gravel, the remainder being from limestone. In the vicinity of Prophetstown wells are usually obtained at less than 50 feet without entering rock and are mainly through gravel. A short dis- tance northwest from Prophetstown, on the north side of Rock River, rock is found at slight depth and it occasionall}^ outcrops. But east from Prophetstown as far as the county limits (16 miles) no records of wells reaching rock were obtained. In T. 20, R. 3 E., which is situated near the western border of the county, the following sections of deep wells were obtained: Wells in T. 30, B. 3 U., Whiteside County, Illinois. Owner or location. Altitude (above tide). Depth. Eemark3. Feet. Feet. F. S. Huntj sec. 3 750 85 Loess and sand, 20 feet ; fine blue sand, 25 or 30 feet ; blue till, 35 or 40 feet ; gravel and Tvater, 5 feet. Chester E^e, sec. 4 740 163 Water from gravel at 160-163 feet ; rock ( ?) at bot- tom. Sclioolhouse sec. 4 ... -. 740 193 Loess, 15 or 20 feet ; blue sand, 10 or 15 feet ; blue till (mainly), 160 feet. Thought to have struck rock at bottom. Mr. Huegins, sec. 9.-... - 740 160 Loess, 15 or 20 feet; blue sand, 10 or 15 feet; blue till with thin gravel beds, 120 feet; white sand, 10 feet. Thought to have struck rock. William Roland, sec. 10 740 147 Little if any rock penetrated. S. Miller, sec. 21 625 690 630 680 65 150 78 70 Wm. Miller, sec. 21 Limestone at bottom. Terminates in gravel. Sec. 33 Several wells 70 feet deep do not enter rock. 720 139 Rook at 126 feet. In the vicinity of Erie wells reach a depth of about 40 feet without entering rock. The majority obtain water at 20 or 30 feet. They are mainly thi-ough a fine sand. A well in section 3 of this townsliip, 47 feet I Part II, p. 828. 618 THE ILLINOIS GLACIAL LOBE. in depth, penetrates 10 feet of clay, below which it is entirely in sand. A well in section 22, altitude 580 feet, enters rock at about 27 feet (Udden). Professor Udden reports the follow ing sections of deep wells south of Rock River in the vicinity of Spring Hill : ^ Wells near Spring Hill, Illinois. Owner or locatiou. Altitude (above tide). Depth. Remarks. Feet. Feet. 630 70 Hervy StiiU, sec. 5 590 40 No rock struck. A. Colbert, sec. 20 660 117 Bowlder clay, 75 feet ; saud, 42 feet. Spring Hill post-office 640 100 No rock struck. B B Brooks sec 29 . .. 660 90 Loess, 20 feet ; blue clay, 60 feet ; gravel at bottom. Sand, 16 feet ; blue clay, 90 feet ; sand with water, Stanley Fuller, sec. 29 660 130 18 feet; rock, 6 feet. David. Uhricli 660 100 Loess aud till, 50 feet; sand, 12 feet: blue till 30 feet ; sand, 8 feet. E. Crozier, sec. 32 650 100 Clay, 60 feet; sand, 40 feet. A. Crozier, sec. 32 640 101 Yellow clay, 10 feet; blue clay, 30 feet; sand at bottom. Sec. 30, near center 640 90 "Hardpan" at bottom, perhaps shale. Mr. Bryant, sec. 36 625 60 Entirely through sand. A well driller at Prophetstown informed the writer that he had struck rock in one well near Spring Hill at 90 feet, and in another at about 100 feet. Probably the deepest well in the vicinity of Spring Hill is on the farm of Mr. Hemy Smead, in sec. SI. This reached a depth of 215 feet, and is thought by Mr. Smead to have terminated in a stony clay, apparently till. As the well mouth is not more than 640 feet above tide, this section indicates the presence of a very deep preglacial valley. Several families in the callage of Spring Hill liave obtained a supply of water from a well only 20 feet in depth, sunk on low sandy ground east of the village. A windmill forces the water to a tank, from which the water is distributed thi'ough pipes to the dwellings. The total expense, aside from laying pipes, is only S5 per annum for each dwelling. The water thus obtained is but moderately hard, and is preferred to the very hard water obtained from the till encountered by wells in the village. In this conuec- ' Coinmiuiic;ited to llir writer. WELLS OF EOCK ISLAND COUNTY, ILLINOIS. 619 tion it may be stated that the wells throughout the sand district of the Green River Basin are re]3orted to furnish a \vater that is less hard than .that obtained froiii the till. ROCK ISLAND COUNTY. GENERAL STATEMENT. Rock Island County occupies a narrow strijj bordering the Mississippi River for a distance of about 50 miles, the city of Rock Island, its comity seat, being about midway of its western border. The area of the county being but 440 square miles, its average width is less than 10 miles. Rock River divides it into two nearly equal portions and forms the eastern border for about 20 miles in the northern part of the county. Meredosia Slough forms the northern border of the county. Between this slough and the vil- lag-e of Hampton there is an island-like tract of upland standing about 150 feet above the Mississippi River, which at times of high water either in the Mississippi or Rock River is completely encircled by streams. Between this u]3land and the city of Moline a gravel -filled valley, called "Pleasant Valley," leads across from Rock River to the Mississippi (see PI. XVIII). Its elevation is but a few feet above the high-water stages of the streams. Between this valley and Rock River is another island-like tract of upland leading from the city of Rock Island eastward to Carbon Cliff, which stands about 150 feet above the Mississippi and Rock rivers. South from Rock River Valley is an upland tract rising gradually southward from an eleva- tion of 150 feet above the river at the bluff to fully 250 feet at the Mercer County line, or to slightly more than 800 feet above tide. The island-like upland tract northeast from Hampton has a denosit of loess 30 or 40 feet in thickness, beneath which there is blue till extending to the rock, which is usually entered at 100 feet or less. The upland between the city of Rock Island and Carbon Cliff has about 40 feet of loess near the Mississippi, but the thickness decreases eastward to scarcely more than 25 feet at Carbon Cliff. Beneath this loess is a thin sheet of glacial drift, rock usually being struck at 50 to 75 feet. The upland south of Rock River has a loess capping about 25 to 40 feet in thickness on the borders of the Rock and Mississijjpi rivers, which decreases southward to 15 feet or less at the Mercer County line. On the brow of the Rock and Mis- sissippi River bluffs rock is usually entered in wells at 50 to 60 feet, but on 620 THE ILLINOIS GLACIAL LOBE. the more elevated upland near the Mercer Count}- line there is nearly 150 feet of drift, mainly a blue till. Tln-oug-hout the county wells usually obtain an abundance of water, without entering the rock, though those on the upland are often sunk to depths of 75 or 100 feet. In the valleys northeast of Rock Island wells are usually obtained at depths of 30 or 40 feet without entering rock. Along Rock River and the portion of the Mississippi Valley below Rock Island the drift deposits are thin and wells frequently enter the rock. INDIVIDUAL WELLS. The following well sections include the deepest of which records have been obtained aside from the artesian wells. About one-half the sections were collected for the Survey by Prof J. A Udden, who has kindly furnished them for publication in this place. Table of irelh in Rock Island County. Owner or location. Altitude (above tide). Depth. Eemarks. Feet. Feet. Sec. 9, T. 19, E. 2 E 700 102 Loess 30 or 40 feet* till 60 feet* limestone a few feet. Cr6aEQ6ry, sec. 15 -.... 680 88 Loess, 12 feet ; quicksand, 27 feet ; black muck ■vritli wood, 9 feet ; blue clay, 40 feet. H. Sadorjs, sec. 16 700 90 Loess, 30 or 40 feet; blue till, 40 feet; shale and limestone, a few feet. W. McRoberts, sec. 17 720 107 Loess, 20 feet ; sand, 64 feet ; rock with i^as, 23 feet. A. Spaid, sec. 17 720 120 Loess, 20 feet; quicksand, 80 feet; gravel, 8 feet; white shale, 12 feet; limestone at bottom. Mrs. Genung, sec. 21 700 100 Loess, 30 or 40 feet; till, 45 or 50 feet; shale and limestone, a few feet. H.McCall,8ec.22 710 185 Loess, 20 feet; soil and wood, 5 feet; sandy drift, 70 feet; sh.ale and limestone, 90 feet. L. Gay lord, sec. 31 670 65 Loess, 40 feet; tine gravel, 25 foot; Coal Measure sandstone wing section: Section in brichyard at Galva. Feet. Loess 15 Black soil (Sangamon) 1' Brown till 30 Blue till 8 Sandstone at bottom. The soil at the base of the loess is well exposed in the clay pit at the brickyards. A large log was found embedded in this soil, but no speci- mens were at hand at the time of the writer's visit to the locality. At Cambridge wells are usually obtained at a.bout 40 feet, in gravel beds below till. Occasionally a well reaches a depth of 75 feet. The drift in that vicinity is about 60 feet in dejith, including 15 or 20 feet of loess. WELLS OF HEiilRY COUNTY. ILLINOIS. 625 The Manual of American Waterworks reports the public water supply to be from a deep well. At Andover, about 5 miles southwest of Cambridg-e, a well penetrates 155 feet of drift, striking rock near the bottom. The lower 20 feet of the drift is sand, the remainder mainly till. At Lynn Center and vicinity several wells enter rock at about 115 feet. The section usually penetrated is as follows: Generalized section of -wells near Lynn Center. Feet. .. 15 Loess Yellow till 10 or 15 Blue till, -svith thin beds of sand 80 At Alpha wells are usually obtained at 15 to 30 feet from a gravelly drift at the base of the loess or near the top of the till, though a few are sunk into the rock. A well at Bolton's sorghum mill enters rock at 75 feet, and several wells southwest of Alpha reach rock at about 70 feet. The drift is mainly blue till. In the vicinity of Orion several deep wells have been made which show the drift to exceed 100 feet. In one instance rock was struck at 150 feet. A well at the creamery, 130 feet in depth, did not reach rock, water being obtained from sand beneath blue till. At Annawan, in the east part of the county, a well at the creamery, 223 feet in depth, entered rock at IM feet. The di-ift is entirely clay (Udden). The following sections of farm wells are reported by Professor Udden: Wells in Henry County, Illinois. Owner and location. Altitude {above tidei. Depth. Kemarka. Feet. Feet. Adam Butzer, sec. 1, T. 18, R. 3 E 650 85 Strikes rook at bottom ; mainly through sand. John Crozler, sec. 7, T. 18, R. 4 E 630 65 No rock struck; upper 30 feet sand, re- mainder bowlder clay. William Arnett, sec. 6, T. 18, E. 4 E 630 75 Upper 40 feet clay, remainder sand. Henry Arnett, sec. 5, T. 18. R. 4 E 645 120 No rock struck. A S Tiifanv sec 5 T 16 R 4 E 610 48 Terminated in gravel. In the northwest part of T. 15. R. 4 E., at an altitude of 775 feet, several wells 60 feet in depth do not reach the rock. MON XXXVIII 40 626 THE ILLINOIS GLACIAL LOBE. BUREAU COUNTY. GENERAL STATEMENT. Bureau County is situated east of Henry, in the north-central part of the State, its southeast border being at the Ilhnois River, near the gi-eat bend. It has an area of 870 square miles, and Princeton is the county seat. The nortliwest part of the count}" is a marshy and sandy district, drained westward by Green River; the central and northeastern portions of the county are drained by Bureau Creek, a tributary of the Illinois; the southwestern portion, which is an elevated district, divides its waters between Grreen River on the north and Spoon River on the south. The bulky morainic system forming the outer border of the Wisconsin drift passes southward through the central portion of this county, leaving a belt 10 or 12 miles in average width on the west Ijorder of the county, which is outside the limits of the Wisconsin drift. This morainic system constitutes the highest portion of the county, much of its main crest being above 900 feet. Yet it apparently crosses and occupies for a few miles the deep preglacial valley through which Rock River is supposed to have dis- charged to the Illinois. The moraine is so bulky as to completely conceal the course of this valley, whose presence is known only by well boring-s. It is probable that the drift in places exceeds 600 feet in depth where the moraine occupies this old valley. The sections' given below will set forth the basis for this opinion. With the exception of a narrow strip on the southern border of the county, and the elevated southwestern portion outside the Wisconsin drift sheet, the drift of this county is a very heavy deposit. The avferage of 29 well sections which reach rock, the majority of which are in the southwest part, show a thickness of 155 feet; but this is evidently much below the average for the county, since 82 records of deep wells whicli do not reach rock and wliich are scattered widely over the county are found to average 190 feet in de})th. It is probable that the average thickness for the county exceeds 200 feet, and it may ])0ssibly reach 300 feet. It is thought that the thickness is greater in this county than in any other within the State. The upper portion of the drift, to a depth of 100 feet or more, in the portion of the county covered l)y the Wisconsin slieet is composed in the main of a blue till. The well sections indicate that the lower portion of WELLS OF BUREAU COUNTY, ILLINOIS. 627 the drift contains a larger proportion of sand and g-ravel than the upper. In the marshy area outside the Wisconsin sheet, which occupies much of the northwest part of the county, there is a surface sand a few feet in depth, but the deep wells usually penetrate a large amount of clay. Sand dunes also cover portions of the elevated moraine. In the southwestern portion of the county the drift is of variable constitution and contains but a small amount of blue till, except where its depth is unusually great. In the eastern portion of the county numerous instances of the occur- rence of a buried soil have been brought to light by the deep wells. In several of the wells which penetrate a buried soil inflammable gas has been obtained, which in some instances has been of sufficient strength to furnish light and fuel for dwellings for a period of several years. Three wells in the village of Lamoille show gas with a pressure of 18 pounds per square inch, another 20 pounds, and still another about 11^ pounds. A dozen or more other wells have a weaker pressure. A well at George Windle's, 2 miles east of Lamoille, has a pressure of 26 pounds per square inch, and one at C. L. Dayton's, 3 miles north of Lamoille, has a pressure of 28 pounds. Many other weaker wells are found between Lamoille and Men- dota. The strong wells usually obtain gas in sand and gravel wliile the weak ones find it in a greenish clay, associated with the buried muck and soil. It seems probable that the gas is formed from the vegetation in these muck beds, though another possible source is found in the escape upward from the underlying Trenton limestone. This limestone in the neighboring States of Indiana and Ohio is found to yield gas in large quantities. The heavy blanket of bowlder clay which occurs in this region forms a suitable barrier to prevent the gas from escaping. A small amount of gas, how- ever, has been noted from the early days of settlement to escape along the borders of Pike Creek in the vicinity of Lamoille.^ INDIVIDUAL WELLS. The public water supply at Princeton is obtained from two wells, 2,093 and 2,525 feet in depth. They apparently each terminate in the Lower Magnesian limestone. The head is about 72 feet below the surface, or 638 feet above tide. The shallower one is cased to a depth of 1,000 feet, ' Tlie statistics concerning these gas vrells were largely contributed by Miss Ella Lemmon, of the Lamoille public schools, and by Mr. George Dean, of Lamoille. 628 THE ILLINOIS GLACIAL LOBE. with inner casing 4| inches in diameter, and has a capacity of 320 gallons per minute. The water is moderately hard and but slightly saline. A par- tial analysis shows only 3.7 grains per gallon of sodium chloride and 28.5 grains of total solids. A portion of the water is from the St. Peter sand- stone at a depth of 1,520 to 1,670 feet, and a portion from the Lower Magnesian at 1,850 to 1,975 feet. The "temperature of the water is 64° F. These wells are of exceptional interest since they strike into a deep part of the preglacial valley which, as indicated above, appears to have been the old coiu'se of Rock River into the Illinois. A careful record was kept of the shallower well, and the following section of drift is reported by Mr. Jacob Miller, of Princeton : Section of drift penetrated in a deep ivell at Princeton. Feet. Clay 47 Sand and gravel 10 Bowlder clay 88 Gravel with Inflammable gas 5 Bowlder clay 25 Sand and gravel 197 Beneath the drift 75 feet of shale was penetrated before hard rock was entered. The deeper well, which was sunk several years earlier, is thought to have reached a depth of 440 feet before entering rock, or about the level of the bottom of this shale. Mr. Miller states that its section was not so carefully kept as that of the later well, and it is possible that the drift was no deeper than 372 feet. This gives the rock floor of the valley an altitude 338 feet above tide, or but 50 feet liigher than low water of the Mississippi at Cairo, 350 miles nearer the seaboard. A well sunk at Prince- ton many years ago, and reported by Judge Shaw in the Geology of Illi- nois, penetrated only 216 feet of diift and was drilled to a depth of but 313 feet.^ This well is scarcely one-half mile distant from the Avells just dis- cussed, yet it seems to ha^'e struck the old bluff'. The village of Buda obtains its public water supply from a well 1,610 feet in depth. The lower 140 feet is thought by citizens to be in St. Peter sandstone. The head is 125 feet below the surface or about 640 feet above tide. The well has a diameter of 6 inches and will supply fully 100 gallons per minute, as was shown by a 24-hour test. A strong water vein was struck at 295 feet, but this is cased out. The casing extends into limestone ' Geology of Illinois, Vol. V, 1873, pp. 172-173. WELLS OF BUREAU COUNTY, ILLmOIS. 629 only a few feet at a deptli of 475 feet. The drift is mainly blue till and is 160 feet in depth. From the base of the diift to 415 feet there is shale and thin beds of sandstone. A bed of coal 4 feet thick was passed through at about 225 feet. The well was mainl}^ in limestone from 415 feet to 1,470 feet, where it is thoug'ht that St. Peter sandstone was entered.^ An artesian well has been sunk at Bureau Junction, in the Illinois Valley, to a depth of 308 feet. A flow of water was obtained without reaching the bottom of the Coal Measures. The well mouth is but 475 feet above tide, and as 135 feet of di-ift was penetrated, the rock floor has an altitude only 340 feet above tide, or about the same as at Princeton. A neighboring well on the farm of Mr. Miller, in sec. 30, T. 15, R. 10 E., enters rock at about the same level above tide. The deepest reliable section of drift reported within the county is that of a well at the village of Ohio, situated near the crest of the moraine in the northern part of the county. This well entered rock at a depth of 412 feet, but as the altitude is 920 feet above tide, the rock floor is 608 feet, or 170 feet higher than in the Princeton well. It is probable, therefore, that the well strikes the blufi" of the old valley. At Neponset, which is situated on the upland outside the Wisconsin drift sheet, in the southwest part of the county, the following complex series of drift deposits was penetrated by a coal shaft: Section of drift beds penetrated in a coal shaft at Neponset. Feet. Loess 12 Sand 4 Blue clay (lowan till ?) 10 Peat, with wood enibedded 3 Marl of dark color 2 Blue clay 8 Sand 3 Till 18 Sand 3 Yellow till 67 Total drift 130 The altitude at this shaft is about 825 feet above tide. The position of the peat and marl beds in the Pleistocene series is not yet determined, nor is it known whether it is of similar age to the buried soil found within the limits of the Wisconsin di-ift in this county. ' Information furnished by Mr. A. J. Fisher, of Buda. 630 THE ILLIISrOIS GLACIAL LOBE. In the following list of deep wells the majority of sections were col- lected for the Survey by Prof. J. A. Udden, who has furnished them for publication in this place. It should be noted that where he uses the word " clay" there is usually till, but such is not always the case. Table of deep wells in Bureau County. Owner or location. Altitude {above tide). Depth. Eemarks. Feet. Feet. In T. 18, R. 7 E., at New Bed- 660 145 Water from sand at bottom ; drift mainly blue clay. ford School. In sec. 34, T. 18, R. 7 E 670 136 Clay, 100 feet ; sand, 36 feet. W. Meek, sec. 9, T. 18, R. 7 E. .. 650 110 Mainly blue clay; no rock. Oscar Wolf, sec. 10, T. 18, R. 7E 680 200 Clay, with sand at bottom. A. J. AViggins, sec. 36, T. 18, .800 270 Clay, 130 feet; coarse gravel, 120 feet; dry sand, 60 R. 7E. feet; bowlder clay and sand, 60 feet; no rock. Mr. Erickson, sec. 36, T. 18, 675 100 Sand, 10 feet; clay, 30 feet. R. 7E. In T. 18, R. 8 E., at Bunker 835 330 Sand, 40 feet; clay, 140 feet; sand, 2 feet; clay, 1?3 HiU School. feet; sand, 15 feet; gas at 210 feet. W. S. Odell, sec. 5, T. 18, E. 8 E . 680 170 Sand, 20 feet; clay, 145 feet ; sand at bottom, 5 feet. W. C. Stearns, sec. 9, T. 18, 750 303 Bowlders in upper 50 feet; clay to 200 feet; sand. R. 8E. a few feet: clay at bottom. Near Walnut, in sec. 9, T. 18, 780 260 Yellow till, 13 feet; sand, 3 feet; till, 60 feet; blue R. 8 E. till, 20 feet; sand, 2 feet; hard till, 15 feet ; sand, 1 foot; blue till, 141 feet; sand, 5 feet; no rock struck. Mr. Waterhouse, sec. 15, T. 18, 815 280 Sand and clay, 165 feet; gravel, 5 feet; clay, 100 R.8E. feet. Sand at bottom. Gas at 190 feet. Mr. Rumberger, sec. 30, T. 18, 810 317 Sand, 100 feet; then clay to bottom. R.8E. Mr. Milliken, sec. 35, T. 18, 830 195 Sand, 40 feet; gravel, 5 feet; remainder, clay. R.8E. Mr. Catterman, sec. 36, T. 18, 800 260 Clay, 250 feet ; sand at bottom. R.8E. Walnut Cheese Factory 710 200 Blue clay, 60 feet ; sand, 10 feet ; reddish clay, 80 feet; gravel, 3 feet; fine sand at bottom. Ohio, village well 920 412 Clay, 150 feet; sand with gas, 50 feet; clay, 40 feet; sandy blue bowlder clay to limestone at bottom. J. Jodor, ne.ar Ohio, in sec. 8.. 890 390 Not certain to have struck rock. G.WiiiiU«,seu.21,T. 18, R. HE. 800 242 Sand, 6 feet; reddish clay, 51 feet; sand, 14 feet; reddish clay, 18 feet; gravel with gas, 14 feet; peaty soil with timber, 18 I'eet; sand, 8 feet; gravel at bottom, 17 feet. WELLS OF BUREAU COUISTY, ILLINOIS. Table of deep wells in Bureau County — Continued. 631 Owner of locatioD. Altitude (above tide). Depth'. Kemarks. Feet. Feet. W. Morris, sec. 31.T. 18, R.ll E . 780 265 Clay, 100 feet; dry sand, 12 feet; clay, 40 feet; cemented gravel, 103 feet (possibly hard till). W. Thomas, sec. 5, T. 17, R. 6 E. 640 98 No rock struck. Robert Smith, sec. 16, T. 17, 630 108 Sand, 40 feet ; blue clay, 60 feet ; sand at bottom. R.6E. G. Pittmans, sec. 2, T. 17, R. 7E. 690 200 No rock struck. Mr. McKnen, sec. 3, T. 17,R.7E. 720 180 Mainly clay ; no rock. Mr. McKueD, sec. 10, T. 17, 710 208 Mainly clay; no rock. E.7E. Mr. Siebel, sec. 8, T. 17, R. 7 E . . 690 160 No rock struck. Mr. White, sec. 13, T. 17, R. 7 E . 750 220 No rock ; mainly bowlder clay. H. Sayers, sec. 14, T. 17, R. 7E. . 750 250 No rock struck. L. Miller, sec. 15, T. 17, R. 7 E . . 680 200 No rock struck. D. A. Miller, sec. 15,T. 17,R.7E. 710 250 No rock struck. J. P. Follet, sec. 16, T. 17,E.7E. 710 250 Clay, 230 feet; sand at bottom ; wood at 60 feet. W. J. McKey, sec. 18, T. 17, 675 140 Bowldery till; no rock. R.7E. D. Weinck, sec. 18, T. 17, R. 7E. 675 140 Sand, 20 feet; blue clay, 100 feet; fine blue sand at bottom. A. Xelson, sec. 21, T. 17, R. 7E. . 670 217 No rock ; clay, 180 feet. O. Smith, sec. 22, T. 17, R. 7 E . . 750 272 No rock struck. C. Samuelson, sec. 24, T. 17, 810 323 Sand, 20 feet; clay, 125 feet; "hardpan," 130 feet; R.7E. clay and sand to bottom, 148 feet. C. Beachler, sec. 9, T. 17, R. 810 270 Clay, 125 feet; sand and gravel with " black stuff" 8E. embedded, 145 feet. P. Erisman, sec. 10, T.17, R.8 E. 750 288 No rock struck. J. Carr, sec. 11. T. 17, R. 8 E . . . . 750 265 Mainly clay; no rock. Mr. Kuaus, sec. 13, T. 17, R. 8 E. 700 317 No rock struck. J. Springer, sec. 25, T.17, R.8 E. 700 200 No rock ; wood in clay at 160 feet. J. Gillam, sec. 6, T. 17, R. 9 E . . . 750 210 No rock struck. E. Beatty, sec. 7, T. 17, R. 9 E . . 725 200 Clay, 120 feet; gravel with gas, 20 feet; clay, 60 feet. Sand at bottom. Mr. Taylor, sec. 13, T.17, R.9 E. 740 165 Clay, 160 feet. Sand with gas at bottom. S. Clark, sec. 24, T. 17, H. 9 E.. . 720 277 Clay, 100 feet; gravel with gas, 17 feet; clay, 40 feet; bowlder clay, 13 feet; gummy clay, 35 feet; sandy hardpan to bottom, 70 feet. A. Dunbar, sec. 26, T. 17, R. 9 E . 730 180 Clay, 160 feet. Black sand at bottom. J. Allen, sec. 35, T. 17, R. 9 E .. . 720 145 Gas in clay at bottom. J. Henzell, sec. 30, T.17, R.IOE. 720 175 In Coal Measures rock, 20 feet, at bottom. Lamoille Shoe Factory 800 118 Gas in dry sand at bottom. Lamoille Mills 800 800 118 130 Gas in dry sand at bottom. Gas in dry sand at bottom. Mrs. Booth, in Lamoille 632 THE ILLIlSrOIS GLACIAL LOBE. Table of deep wells in Bureau County — Continued. Owner or location. Altitude (above tide) Depth. Kemarke. E. SteTenson. iu Lamoille L. Hopps, near Lamoille C. L. Dayton, near Lamoille .. . Mr. Perkins, sec. 5, T.17, E.ll E A. Searle, see. 32, T. 16, E. 10 E . M. Frey, sec. 22, T. 16, E. 10 E .. One-half mile north of Depue. K". Anderson, sec. 30 Mr. Seaton, sec. 9 Seaton and Ticinity Near Hollo way ville Ladd, coal boring Princeton artesian well Princeton, old artesian well Mr. Eickmeyer, 3 miles north- east of Princeton. A. T. AVeise, sec.36, T.16, E.9 E . Sec. 20, T. 16, E. 9 E In T. 16, E. 8 E., at Mr. Kauf- mann's, sec. 13. Company's TveU, sec. 16, T. 16, E.8 E. J. Sapp, sec. 18, T. 16, E. 8 E.. .. L. L. Lay, sec. 31, T. 16, E. 8 E . . J. Pottorf, sec. 32, T. 16, E. 8 E . S. W. i sec. 32, T. 16, R. 8 E . . . . C. Hays, at Wyanet Wyanet prospect boring . Lovejoy coal shaft County farm, east of Wyanet.. J. B. Stewart, near Wyanet . .. Buda, village well Mrs. Mammon, in Hnda E. Harbrook, sec. 8,T. 16, E. 7E Nels Olson, sec. 12, T. 16, E. 7E. ShefSeld and vicinity Mineral, railway well 800 800 800 750 600 Feet. 150 130 207 147 650 265 680 120 490 50 520 300 700 100 625 45 700 80 656 175 700 372 700 313 670 272 485 395 700 260 690 260 120 645 172 770 130 720 287 700 80 660 140 660 112 700 62 600 160 700 150 760 120 780 232 670 150 750 220 675 10 638 60 Gas well; uo rock. Gas jn sand at bottom. Gas and water in sand at bottom. Yellow till, 14 feet; blue till, 117 feet; hard gray till, 15 feet. Sand with gas at bottom. No rock struck ; mainly sand. No rock; mainly sand. Entirely sand. Enters rock at about 100 feet. Enters rock near bottom. Drift, about 45 or 50 feet. Mainly till : sand at bottom. Rock entered at 175 feet. Bock entered at 372 feet. Eock entered at 216 feet. Clay, 90 feet ; gravel and sand, 182 feet. Eock entered at 160 feet. No rock struck. Clay, 125 feet. Sand and clay to bottom. Sand, 40 feet ; blue till, 80 feet. Sand at bottom. No rock. Gas iu sand at 85 feet. No rock. Gas in old soil. Eockf at bottom. Sandstone entered at 80 feet. Clay, 40 feet ; sand, 10 feet ; blue clay, 25 feet; clay with sand veins to bottom, 50 feet. Eock entered at 112 feet. Yellow till, 20 feet; sand, 12 feet; blue till, 30 feet. Sandstone above coal. Not certain whether rock was struck. Mainly till. Wood and sand at bottom. Till, 70 feet; sand, 10 feet. Till with thin sand beds to bottom. Artesian well recently sunk has 160 feet of drift. Till, 85 feet. Eemainder mainly sand. Clay, 75 feet. Fine blue sand to bottom. Mainly clay; lower 50 feet sand. Eock entered at 10 to 20 feet. In blue olav at bottom. WELLS OF PUTNAM COUNTY, ILLINOIS. Table of deep loells in Bureau County — Continued. 633 Owner or location. Altitude (above tide). Depth. Kemarks. Feet. Feet. A. Stevens, sec. 1, T. 15, E. 7 E . . 750 200 Enters rock at 150 feet. D. Brady, sec. 23, T. 15, E. 7 E . . 800 200 Enters rock at 150 feet. In T. 15, R. 8 E., at G. Kitter- 540 90 Entirely sand. man's, sec. 1. Frank Stevens, sec. 14, T. 15, 720 116 Enters rock at 116 feet. E.8E. Mr. Whiting, sec.l4,T. 15, E.8E 700 100 Enters rock at 100 feet. A, Greenman, sec. 20, T. 15, 650 212 Blue clay, 110 feet; sand, 102 feet. R.9E. H. Benson, sec. 21, T. 15, R. 9 E. 640 SCO Clay, 120 feet. Remainder sand. Bureau Junction 475 308 Drift 135 feet S. Russell, sec. 5, T. 15, E. 10 E . 600 196 No rock struck. C. Averill, sec. 7, T. 15, E. 10 E . 500 130 Entirely sand. J. Eudberg, sec. 8, T. 15, E. 10 E 600 245 No rock ; mainly sand. Mr. Miller, sec. 30, T. 15, R. lOE 445 260 Drift about 100 feet. PUTNAM COUNTY. GENERAL STATEMENT. Putnam County is situated southeast of Biireau, immediatelj soutli of the great bend of the Illinois, and is traversed in a southward course by that stream. It is one of the smallest counties in the State, its area being but 170 square miles, and Hennepin is its county seat. The county is situated mainly east of the Illinois River, there being scarcely 60 square miles on the west side of the stream. The valley of the Illinois River in this county has a width of about 5 miles. The remainder of the county is an upland standing 200 to 300 feet above the level of the river. The most elevated part is on the eastern border near Mount Palatine, where an altitude of 725 to 750 feet is attained. Throughout the county there is a heavy deposit of di'ift, averaging fully 150 feet in thickness. The upper portion on the uplands to a depth of 75 or 100 feet is mainly bowlder clay, but the lower portion, and nearly all the di-ift in the valley of the Illinois, is sand and gravel. The list of deejj wells presented below was furnished by Prof J. A. Udden, with the exception of the artesian well at Hennepin, data concerning which were furnished by A. T. Purviance, county clerk. 634 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS. The Hennepin artesian well is 800 feet in depth and has a head sufficient to cany the water at least 50 feet above the surface. It has a discharge of 80 gallons per minute from a 4-inch pipe. There is a slight salinity, but the water is not unpleasant to the taste. The well is cased nearly to the bottom and the water has a temperature of 58° F. The drift is about 150 feet in thickness. The altitude of the well being scarcely 500 feet, the rock floor is but 350 feet above tide, or nearly as low as at the wells in Princeton and Bureau Junction. The Putnam City artesian well obtains water from the Coal Measures, but the depth was not ascertained. It penetrated about 200 feet of drift, and entered rock at a level slightly below 350 feet above tide. Table of icells in Putnam County, by Prof. J. A. Udden. Owner or location. Altitude (above tide). Depth. Eemark3. Feet. Feet. Mr. Wheeler, near Putnam 470 107 Clay, 12 feet; sand, 35 feet; blue clay, 60 feet ; sand- City. ^ stone at bottom. C. Eeed, sec. 25, T. 14, R. 9 E . . . 620 231 Clay, 16 feet; gravel, 12 feet; gray clay, 85 feet; sand and gravel, 108 feet; Coal Pleasures at bot- tom. F. Willmann, sec. 33, T. 33, 670 280 Clay, 75 feet; sand, 9 feet; reddish clay, 19 feet; E.1W. saud, ofeet; red clay, 15 feet; sand, 45 feet; al- ternations of clay and sand to bottom; no rock. Granville creamery 670 135 Blue till, 30 feet; reddish clay, 50 feet; saud and gravel, 48 feet; rock, 7 feet. W. Sill, 860. 17, T. 32, R. 1 W . . . 710 114 No rook struck. J. Henning, sec. 22, T. 32, 730 182 Yellow clay, 12feet; blue clay, 80 feet; "hardpau," R. 1 W. 90 feet; rock near bottom. Sec. 11, T. 32, E. 2 W 580 200 Rock entered at 155 feet; drift maiuly sand and gravel. Sec. 14, T. 32, R. 2 W 600 690 690 710 226 280 100 160 No rook struck ; mainly bowlder clay. Bottom in sand. Sec. 5, T. 31, R. 1 W Sec. 6, T. 31, R. 1 W Bottom iu sand. J. Mills, sec. 11, T. 31, R. 1 W. . . Rock entered near bottom. J. Kays, sec. 30, T. 31, R. 1 W. . . 660 240 Maiuly till; gravel at bottom. W. Glenn, sec. 31, T. 31, R. 1 W . 670 160 In olay at bottom. Mount Palatine 730 150 Mainly till; no rock struck. WELLS OF LASALLE COUNTY, ILLINOIS. 635 LASALLE COUNTY. GENERAL STATEMENT. Lasalle County is situated in the north-central part of the State, imme- diately east of Bureau and Putnam counties and above the bend of the Illinois River. That river traverses the county nearly central from east to west. It is the second county in size, being exceeded only by McLean County, and has an area of 1,152 square miles. Ottawa, the county seat, is situated near its geographic center, at the junction of Fox River with the Illinois. Fox River traverses the northeastern portion in a southwestward course and receives the drainage of much of the northern half of the county. Vermilion River traverses the southern portion of the county in a northwestward course, entering the Illinois opposite the city of Lasalle and dividing the portion south of the Illinois into nearly equal parts. The Little Vermilion drains the northwest portion of the county in a southward course and enters the Illinois at Lasalle. The most elevated portion of the county is in the northwest corner, which is occupied by the inner portion of the Bloomington morainic system. The altitude here reaches about 900 feet above tide. Much of the uplands in the county stand below 700 feet. The extreme southwestern portion, however, rises to about 750 feet, and the Marseilles moraine on the eastern border of the county has a crest line about 750 feet above tide. The greater portion of the surface is nearly plane. There is, however, aside from the two moraines just mentioned, a small morainic belt (Farm Ridge) which occupies the upland immediately east of Little and Big Vermilion rivers, crossing the Illinois River between Utica and Lasalle. The principal streams of the county have excavated valleys iii the rock, and wells on the uplands frequently enter rock at depths of 50 feet or less, except in the elevated portions referred to in the northwest, southwest, and east parts of the county. In the northwest part the thickness of the drift exceeds 200 feet. In the southwest part it is apparently about 150 feet. In the eastern part, along the Marseilles moraine, it is 200 feet or more. The average distance to rock in 55 of the deep wells on the upland and 8 deep wells in the valleys is 99 feet. Records were obtained of 85 other deep wells which do not enter rock, though their average depth is 89 feet. They are largely situated on the Marseilles moraine. The wells entering rock 636 THE ILLINOIS GLACIAL LOBE. here discussed are distributed with some imiformity over the entire count}', except the portion southwest of Vermihon River, where very few records have been obtained. The upper portion of the drift, and indeed the deposit penetrated by nearly the entire depth of the wells throughout the county, is blue till. There are, however, small areas in which the drift contains a larger amount of sand and gravel than till, and thin beds of gravel or sand appear to be quite generally present in the till. These afford water for the shallow wells on the farms and in villages. The public wells in cities and villages and the stock wells on the farms are iisually sunk to considerable depth. On the north border of the county, near Earlville, many flowing wells have been obtained from the drift, usually at depths of 25 to 50 feet, or even less, but occasionally of greater depth. Strong hydi-ostatic pressure is exhibited by wells situated on the lower portion of the slopes of the large moraines in the northwestern and in the eastern part of the county. This pressure is in all probability due to absorption of the water on more elevated portions of the moraine. The flowing well district near Earlville is thus related to the moraine on the northwest. A few other flowing wells occur in the county in valleys or lowland tracts, which are probably supplied from the neighboring higher land. Many artesian wells are obtained from the St. Peter sandstone. Lower Magnesian limestones and sandstone, and the Potsdam sandstone along the borders of the Illinois River, and occasionally at points on the uplands, as appears in the discussion below. INDIVIDUAL WELLS. The city of Mendota, in the northwest part of the county, obtains its public water supply from wells about 400 feet in depth sunk to the St. Peter sandstone. A portion of the water may be derived from higher horizons. The head is sufficient to bring the water within 4U feet of the sui-face, or to about 710 feet above tide, which is somewhat higher than the head for the St. Peter in this region. The private wells at Mendota are usually obtained at depths of but 12 to 20 feet in beds of sand or gravel between the yellow and blue tills. A few deep wells liave been sunk in the vicinity of the city, which show the di-ift to be 160 to 200 feet in depth. An old soil is frequently passed through in the lower part of the drift at a dei)tli of 100 feet or more. The till above the soil is usually of a blue WELLS OF LASALLE COUNTY, ILLINOIS. 637 color and comparatively soft, being apparently of Wisconsin age. That below the soil is of a brown or gra}^ color and usually is rather hard. Several gas wells have been obtained near the level of this old soil, as in the neighboring portion of Bureau County, discussed above. Here, as in Bureau County, the gas is probably largely derived from decomposition of the vegetation in the buried soils and in the drift, but a portion may be derived by escape from the underlying Trenton limestone. At Earlville, near the north border of the county, the public water supply is from an 8-inch tubular well 150 feet in depth, which terminates in limestone. The private wells in that vicinity are 30 to 60 feet in depth and usually obtain water in gravel below till, though a few enter the rock.-' The public water supply at the city of Peru is obtained from an arte- sian well 1,250 feet in depth, which terminates probably above the St. Peter sandstone. Another well at the zinc works in Peru, 1,360 feet in depth, obtains its supply from the St. Peter at the bottom and probably in part from the limestones above this sandstone. The waterworks well is estimated to have a capacity of 450 gallons per minute and its head is sufficient to cause an ovei-flow at 85 feet above the well mouth or 560 feet above tide. An analysis of the water has been published in the Seventeenth Annual Report of this Survey.^ This analysis shows but 16 grains of sodium chloride per gallon and the water is considered of excellent quality. There is about 130 feet of drift in the Illinois Valley at this point. This gives the rock floor an altitude but 330 feet above tide, which is fully as low as at wells in this valley in Bureau and Putnam counties. This city seems to stand a few miles east from the main preglacial valley. The city of Lasalle obtains its public water supply in part from springs and in part from two artesian wells obtained in the Goal Measures sand- stone at depths of 332 and 530 feet. The springs yield about 1,500,000 gallons a day and the wells about one-third that amount (C. H. Nicolet, city engineer.) Many private wells are obtained in Lasalle at depths of 10 to 30 feet in gravel near the base of the drift. The Illinois River from Lasalle eastward being outside the line of the preglacial valley, which it enters west of this city, rock is found at comparatively slight depths in the valley bottom. ' The flowing wells near Earlville are discussed in the Seventeenth Annual EeBort of this Survey (Part II, pp. 779-780). - Part II, p. 828. 638 THE ILLINOIS GLACIAL LOBE. At the villag-e of Utica many artesian wells have been obtained in the Lower Magnesian limestone. The strongest wells are obtained at depths of 215 to 330 feet, but many are of much less depth. The water rises to a height of about 50 feet above the surface, or 525 feet above tide. The sti'ongest wells have an estimated capacity of about 150 gallons a minute, or 200,000 gallons a day. Tlae city of Ottawa formerly obtained much of its public water supply fi'om shallow wells piped to a reservoir on the south bluff of the river and disti'ibuted by g•ra^^ty to the city. It is now supplied from sis artesian wells and Fox River. A lai'ge number of private artesian wells are sunk through the St. Peter sandstone to the underlying strata, from which an excellent quality of water overflows. It is estimated that there are not less than 200 such wells in the (dty and vicinity. The great majority are but 300 to 400 feet in depth. One boring was sunk, however, to a depth of 1,840 feet and obtained water from the Potsdam, which has a sti'ong ■flow in the lower 200 feet. The head is estimated to reach 175 feet above the well mouth, or 705 feet above tide The quality of the water is vari- able in the several wells, but is usually slightly sulphurous and moderately hard. The salinity is very slight. At the village of Marseilles a large number of private artesian wells have been sunk which obtain water from the St. Peter sandstone at depths of 100 to 200 feet. The head is remarkably low, being but 12 to 20 feet above the surface, or scarcely 500 feet above tide. The wells are ordi- narily but 2 inches in diameter, with a nozzle 1 inch in diameter. Their rate of flow has appreciably decreased within the past 15 years and at pres- ent an average well will discharge but 4 or 5 gallons a minute. For fire purposes the village has a system of waterworks which pumps its supply from the Illinois River. The villao-e of Seneca, situated in the Illinois Vallev near the east border of the county, is also supplied with several private artesian wells, which obtain water from the St. Peter or lower strata at depths ranging from 350 to 680 feet. The strongest How is thought to be obtained at a depth of about 630 feet. The water is slightly sulphurous, but is other- wise of pleasant taste. The head, like that of the wells at Marseilles, is remarkably low, being scarcely more than 20 feet above the surface at the wells, or 525 feet above tide. WELLS OF LASALLE COUNTY, ILLINOIS. 639 Streator, a city located on the southern border of the county, obtains its public supply by pumping from Vermilion River. Many private wells are obtained at depths of 20 to 40 feet, from gravel in the drift. An artesian well was sunk in this city to a depth of 2,496 feet, terminating in the Potsdam sandstone. Water was struck in the St. Peter sandstone at 450 feet, which has a head 678 feet above tide, or 40 feet below the surface. In the Lower Magnesian strata the head was increased a few feet, and in the Potsdam, at 2,170 to 2,496 feet, water was struck which has a head 45 feet above the surface, or 663 feet above tide. A section of this well and also of the deepest well at Ottawa has been published in the Seven- teenth Annual Report of this Surve}^.^ At Vermilionville, in the valley of Vermilion River, a few miles below Streator, a boring made for oil reached a depth of 1,000 feet and obtained a strong flow of excellent water. Numerous springs occur along the Ver- milion River below Streator, which are in part from the St. Peter and in part from Coal Measures. The water is usually of excellent quality. An artesian well 2,189 feet in depth was made by Mr. Pedicord on the uplands north of the Illinois River near Marseilles, at an altitude about 700 feet above tide. When cased, an overflow from a depth of 1,850 feet was obtained. The well penetrated 169 feet of glacial drift.^ The following table of deep wells along the Marseilles moraine begins in the northeast part of the county and proceeds southward. The moraine is situated immediately east of Fox River as far south as the mouth of that stream. Upon crossing the Illinois it bears east of south, leaving the county near the southeast corner. The width, including the slopes, is 5 or 6 miles. Wells along the Marseilles moraine in eastern Lasalle County. Owner or location. Altitude (above tide) . Depth. Eemarks. Feet. Feet. Sec. 23, T. 35, R. 5 E 675 137 St. Peter sandstone at 130 feet; drift mainly blue till. See.23, T.35, R.5E 650 100 Three "wells about 100 feet with no ronV Sec. 33, T. 35, R. 5 E 700 153 St. Peter sandstone at bottom; drift mainly blue till. Sec. 4, T. 34, R. 5 E 720 233 Till, 138 feet ; sand and gravel, 13 feet ; blue clay, 17 feet; St. Peter simdstone, 65 feet. Sec. 0, T. 34, R. 5 E 650 105 strikes rock at bottom. 'Part II, pp. 798-799. - Geol. of Illinois, Vol. VII, p. 50. 640 THE ILLmOiC GLACIAL LOBE. Wells along the Marseilles moraine in eastern Lasalle County — Continued. Owuer or location. Altitude (above tide) Depth. Remarks. Sec. 5, T. 34, K. 5 E Sec. 9, T. 3i, R. 5 E .. Sec. 6, T. 34, R. 5 E . . Sec. 9, T. 34, R. 5 E . . Sec. 16, T. 34, R. 5 E . Sec. 18, T. .34, R. .5 E , Sec. 27, T. 34, R. 5 E Sec. 22, T. 34, E. 5 E Sec. 24, T. 34, R. 5 E . Sec. 28, T. 34, R. 5 E , Sec. 11, T. 34, E. 4 E . Sec.l4,T.34,R.4E... Dan way and vicinity. Sec. 13, T. 34, R. 4 E . Sec. 23, T. 34, R. 4 E . Sec. 34, T. 34, R. 4 E , Sec. 35, T. 34, E. 4 E Sees. 3 and 4, T. 33, E. 5 E . A. Irwin, bluff north of Seneca Sec. 20, T. 38, E. 4 E Sec. 26, T. 33, R. 4 E , Sec. 26, T. 33, R. 4 E Bluff south of Marseilles. Sec. 36, T. 33, E. 4 E Sec. 21, T. 33, E. 5 E Sec. 1, T. 32, E. 4 E Sec. 2, T. 32, E. 4 E Sec. 2, T. 32, R. 4 E Sec. 35, T. 32, R. 4 E Sec.29,T.32,R.5E Sec. 30, T. 32, R. 5 E Feet. 675 700 Feet. 160 196 650 100 675 210 700 200 700 200 650 160 700 185 650 100 700 180 650 195 650 100 690 100 675 107 650 118 620 68 650 85 650 610 108 630 215 740 219 720 252 675 184 700 177 675 80 740 232 725 220 725 194 700 108 700 130 700 128 Till, 100 feet ; sand, 10 or 15 feet ; clay, 10 or 15 feet ; Coal Measures shale, etc., 35 feet; St. Peter sand- stone near bottom. St. Peter sandstone near bottom; hard brown till below blue till at 166 feet. Mainly sand and gravel ; no rock. No rock struck. St. Peter (?) sandstone entered near bottom below drift, lu gravel at bottom. St. Peter ( f ) sandstone at bottom. No rock struck. Coal Measures sandstone at bottom. Mainly till ; hard rock at bottom. Till, 93 feet; gravel, 7 feet; "potter's clay," 40 feet; sandstone, 55 feet ; St. Peter sandstone near bottom. In sand below till. Several wells 100 feet deep do not enter rock; mainly through till. Three wells, 100 to 107 feet ; mainly through till ; no rock. Yellow till, 15 feet; blue till, 75 feet; black clay or soil, 8 feet; sand, 20 feet; no rock. Soft till, 28 feet; hard, dry till, 40 feet; rock at bottom. No rock; mainly blue till. Molluscan shells in sand at 6 to 10 feet; wells, 10 to 33 feet. No rock; mainly till. Drift, 40 feet; St. Peter sandstone at 215 feet. Till, 170 feet; sand and till to bottom. Till, 198 feet; gray, sandy clay, 38 feet; sandstone, 14 feet; shale, 2 feet. Till, 165 feet; sand and gravel to bottom. Till, 170 feet; sand at bottom. Yellow clay, 10 feet; gravel, 70 feet. Till, 1.50 feet ; remainder sand and till. Till, 150 feet; remainder sand and till. Till, 116 feet; s.iud and till to bottom. Entirely through till. Eniirely through till. Till, 125 feet; saud at bottom. WELLS OF LASALLE COUNTY, ILLINOIS. 641 Wells along the Marseilles moraine in eastern Lasalle County — Continued. Owner or location. Altitude (above tide). Deptli. Remarks. Feet. Feet. Sec. 9 T. 31, E.5 E 720 181 Eoct ^ at bottom Sec. 14, T. 31, E. 5 E 690 103 Mainly till ; rock at bottom. Drift, mainly till, 285 feet; Coal Measures and Mr. Gate, near Ransom 720 543 limestone (Trenton?) extending to St. Peter sandstone at 510 feet. S. deals, near Ransom 720 370 Drift, mainly till, 270 feet; Coal Measures, 100 feet; limestone (Trenton?) near bottom. Sec.5, T.31, E.5 E 720 144 Mainly till; sand at bottom. Sec. 35, T. 31, E. 5 E 700 130 Sec.36, T. 31, R.5E 675 160 Enters rock at 120 feet Sec. 27, T. 31, E. 5 E 700 175 Gas well from drift sand; water stands 6 feet below surface. Sec. 36, T. 31, E. 4E. ; also sees. 700 160 Several wells about 160 feet ; none enter rock. 25 and 26. The following table includes the deepest well sections obtained in other parts of the county aside from the artesian wells discussed above :^ Wells of Lasalle County outside the Marseilles moraine. Owner or location. Altitude (abovetide). Depth. RemarUd. Feet Feet. Sec. 11, T. 36, E. 5 E . 650 80 Eive wells enter first rock at about 20 feet and St. Peter sandstone at 35 or 40 feet. Sec. 11, T. 36, E. 5 E . 650 20 Black muck with wood and leaves below till at bottom. Sec. 9, T. 36, E. 3 E 700 180 Boring for coal struck old soil at 35 to 40 feet and entered rock at 50 feet. Sec. 9, T. 36, E. 3 E 680 20 Two flowing wells in Indian Creek Valley. Thirty flowing wells 18 to 85 feet in depth from T. 36, Es. 2 and 3 E 690 sand below till. D. Ivnight, sec. 34, T. 36, E. 4 E. 675 80 Enters rock at 63 feet; well half mile west enters rock at 63 feet. NW. part of T. 36, E. 1 E 850 200 Several wells 150 to 200 feet, with no rock. li miles north of Mendota 800 198 Gas at 75 and 128 feet; old soil at 178 feet; water rises 90 feet from gravel at bottom. Mr. Miller, near Mendota 725 144 Flowing well from gravel below till ; a buried soil from 120 to 125 feet. 'For sections of several wells in the vicinity of Mendota the writer is indebted to Mr. L. E. Curtis of that city. MON XXXVIII 4:1 642 THE ILLINOIS GLACIAL LOBE. Wells of Lasalle County outside the Marseilles moraine — Continued. Owuer or locution. Altitude, (above tide). Beptb. Remarks. Feet. Feet. Porterfield's gas wells near 700 to 725 176 Five wells 120 to 176 feet ; deepest reaches rock ; Mendota, black muck or soil with leached subsoil between till sheets at about 600 feet above tide; gas in sand above old soil. Blaucliard's gas well, near 750 218 Yellow till, 10 feet; blue till, 56 feet; sand with Mendota. gas, 96 feet ; Trenton limestone, 56 feet. Sec. 26, T. 35, R. 1 E 610 46 Trenton limestone at 46 feet. Mr. Fiufsen, 6 miles S. from 700 143 Well enters Coal Measures shale below drift at 143 Mendota. feet. Sec. 32 T. 35 R. 1 E 650 40 Gas from trravel below till. Sec. 26, T. 35, R. 2 E 700 121 Three wells of similar depth and structure : yellow till, 16 feet; blue till, 85 feet ; gravel, 20 feet. Sec. 23, T. 35, R. 2 E 660 675 63 54 Sec. 32 T. 35, R. 2 E No rock; mainly till. Rock at bottom; mainly till. Two wells. No rock ; mainly blue till. No rock; maiuly blue till. Entirely till. Till, 40 feet; sand and gravel, 64 feet. Sec. 35, T. 35, R. 2 E 700 98 Sec. 34, T. 35, R. 2 E . . . . 675 76 Sec. 5. T. 34, R. 2 E 700 80 Sec. 4, T. 34, R. 2 E 700 91 J. Bo wen, near Serena 600 104 H. Bowen, near Serena 600 75 Enters sandstone at bottom. 635 100 Mainly blue till, 50 or 60 feet; sand and gravel. 15 or 20 feet; St. Peter sandstone at 75 or 100 feet. 641 591 620 40 16 100 Mainly till; no rock. St. Peter sandstone at 12 to 16 feet. Sec 27 T. 33 R.2 E . ... No rock ; mainly till. No rock : mainly till. Sec.33 T.33,R.2 E 620 100 Sec. 23 T. 33, R. 5 E 600 88 Very hard red till near bottom under soft blue till. Sec.5, T.33, R.2E 650 625 47 50 Sec. 28, T. 33, R. 2 E Rook at 50 feet. 585 30 Gravel, 30 feet ; till at bottom. Ottawa waterworks 600 27 Mainly gravel and sand; no rock. Till, 120 feet; saud and gravel to bottom. Orand Ridge Station 663 153 Sec. 21 T. 32, K. 3 E , 650 200 Till, 140 feet; sand and gravel, 60 feet. Mainly sand ; no rock. No rock; blue clay with some sand. Farm Ridge 680 50 R. Williams, 9 miles north of 650 140 Streator. One mile from preceding (i50 187 Water rises 87 feet. One mile from preceding 650 315 St. Peter sandstone at bottom ; water brackish. Sec 17 T. 32, R. 1 E 675 150 Till about 50 feet; sand about 100 feet; rocli at bottom. Sec 18 T 31 R 4 E 610 660 65 100 Mainly saud and gravel; shale at bottom. No rock ; entirely till. Sec 34. T. 31, R. 4 E WELLS OF KENDALL COUNTY, ILLINOIS. 643 KENDALL COUNTY. GENEKAL STATEMENT. Kendall is a small county, with an area of but 330 square miles, sit- uated east of tlie northern part of Lasalle and the southern part of Dekalb County, with Yorkville as the county seat. Fox River crosses its north- western portion in a southwestward course, and nearly half the county is tributary to it. The remainder of the county di-ains southeastward directly to the Illinois River through Aux Sable Creek and smaller streams. The Marseilles moraine traverses this county centrally from northeast to southwest, following- the southeast border of Fox River Valley, or rather Fox River Valley- follows the outer border of this moraine, the course of the stream being determined by the moraine. The remainder of the county has a plane surface, except the east border, which is occupied by the Minooka till ridge. The drift is of moderate thickness, averaging probably 100 feet. A small area in the southern part is very thinly coated and there are numerous rock outcrops along the Fox River Valley. The heaviest drift, apparentl}', is along the line of the Marseilles moraine, where, as shown in the table below, the thickness usually exceeds 150 feet. An extensive gravelh' area occupies townships bordering Fox River. The gravel extends usually as deep as wells have penetrated, and may con- tinue to the underlying rock. The remainder of the county outside the moraine apparently has much sand and gravel in the lower part of the drift. The Marseilles moraine and the plain to the southeast are characterized by a heavy sheet of till, though there are limited areas in which wells pene- trate a large amount of sand or gravel. The Minooka Ridg'e, also, is com- posed largel}' of till. Wells are ordinarily obtained in this county at de^jths of 25 to 35 feet. The deeper ones are largely found along the Marseilles and Minooka ridges. INDIVIDUAL WELLS. At Piano, in the northwest part of the county, several wells reach a depth of 45 feet without entering rock, and are mainly tlu'ough sand and gravel. The public water supply is from a well.' North of this village for 2 or 3 miles wells usually peneti'ate about 20 feet of till and then enter sand and gravel, in which they terminate at depths of 40 or 50 feet. One ' Manual of American Waterworks. 1897. g44 THE ILLINOIS GLACIAL LOBE. well, however, in see. 11, was sunk to a depth of 196 feet and entered rock at about 150 feet. Mr. Otis Latham made a well in Piano which struck an old soil containing- grass leaves beneath till at a depth of about 25 feet. Southwest of Piano, in sees. 29 and 31, two wells 44 and 69 feet in depth are mainlv tln-ouo-h sand, and do not enter rock. At Oswego there is a very thin coating of gravelly drift on the rock, and wells are usually sunk into the limestone about to the level of Fox River, 30 or 40 feet. The public water supply is from drilled wells.' For about 5 miles below Oswego there is a gravel plain on the east side of Fox River a mile or more in width, on which wells are obtained at depths of 10 to 30 feet without entering rock. At Yorkville the public water supply is obtained from springs in the Marseilles moraine which borders the town on the southeast. The private wells are obtained at depths of 15 to 30 feet and seldom enter the rock. At Millington flowing wells may be obtained from the St. Peter sand- stone at slight depth. Two at the residence of Dr. J. A. Freeman, 78 feet in depth, enter this sandstone 27 feet. The drift, with the exception of about 20 feet of gravel at surface, is mainly till. The wells are ordinarily obtained in this village at depths of 12 to 20 feet in the gravel of the Fox River Valley. In the vicinity of the village of Plattville on the plain east of the Marseilles moraine many flowing wells have been obtained. The majority have a depth of but 30 to 45 feet, but occasionally a depth of 70 feet or more is reached. The water is obtained in sand below till and the absorb- ing area is, in all probability, in the Marseilles moraine on the west. A deep well 2 miles north of Plattville at an altitude about 50 feet above the village, or 650 feet above tide, reached a depth of 550 feet and entered St. Peter sandstone at 511 feet. A large amount of water is obtained, but it does not overflow. Rock was entered at 143 feet and is mainly limestone down to the St. Peter sandstone. A well 1^ miles east of Plattville at about the same elevation (600 feet) entered rock at 40 feet and was drilled to a depth of 80 feet. In the vicinity of Lisbon, where the altitude is 625 to 640 feet, limestone is entered at a depth of 10 feet or less, and wells are obtained at depths of only 30 to 50 feet. For 4 or 5 miles northeast of Lisbon rock is usually ' Mauuul of American Waterworks, 1897. WELLS OF KENDALL COUNTY, ILLINOIS. 645 entered at less than 50 feet, but occasionally a well reaches a depth of 90 feet without entering it. Three wells in sees. 11 and 12, T. 35, R. 7 E., are 48, 50, and 90 feet in depth without reaching' rock, and the water has a head nearly level with the surface. The altitude is about 40 feet lower than at Lisbon, or 600 feet above tide. The following- list of wells along the Marseilles moraine include the deepest of which records were obtained. Many shallower wells occru- which obtain water at depths of 30 to 40 feet or less. The sections are taken in order, beginning at the northeast corner of the county and passing southwestward : Wells on the Marseilles moraine in Kendall County. Owner or location. Altitude (above tide). Depth. Kemarks. Feet. Feet. Sec. 24, T. 37, E. 8 E 700 750 200 152 Enters rock at about 200 feet. Sec. 24, T. 37, R. 8 E Yellow till, 18 feet ; blue till, 108 feet ; sand with clay streaks, 24 feet ; gravel at bottom. Mr. Miner, 4 miles southeast of 700 121 No rock; till 100, sand, 21 feet. Oswego. Sees. 31 and 32, T. 37, R. 8 E ... 700 100 Several wells; mainly till; no rock. Sec. 5, T. 36, R. 8 E 725 150 Enters rock at about 100 feet. Sees. 22 and 28, T. 36, R. 6 E . . . 675 120 Several wells; mainly blue till; no rock. G. Whitfield, near Millbrook . . 650 60 Sand below till. Mr. Darnell, 2 miles south of 700 190 Mainly blue till, 160 feet; old soil with wood, 2 to Millbrook. 4 feet; blue sand to bottom. Newark village Avell 640 700 110 141 No rock; mainly till. C. Sleezer, east of Newark Mainly till ; rock at bottom. F. Sleezer, east of Newark 700 140 Entirely till. S. Sleezer, east of Newark 725 160 No water or rock struck. I. Anderson, east of Newark .. 725 160 Soft till, 100 feet; hard till with wood near bottom, 60 feet; St. Peter sandstone at bottom. Sec. 4, T. 35, R. 6 E 725 725 150 161 Entirely in till. Limestone at bottom. Sec. 4, T. 35, R. 6 E Holderman's Grove 700 50 Mainly till; no rock. Big Grove 725 150 Two wells enter limestone below till at this depth. GRUNDY COUNTY. GENERAL STATEMENT. Grundy County is situated east of Lasalle County and includes the head of the Illinois River. It has an area of 440 square miles, and Morris 646 THE ILLINOIS GLACIAL LOBE. is the county seat. The Illinois River leads westward througli the nortli- centi'al portion of the county. The tributaries of the Illinois, however, have an eastward course, those on the north bearing southeast, and those on the south northeast. This peculiar feature, as previouslv indicated, is occasioned by the slopes of the plain, or basin, encircled on the north, west, and south by the Marseilles moraine, from which there is a gradual descent to the center of the basin near the head of the Illinois River. The river has cut this moraine at the town of Marseilles and thus opened an outlet from the basin. The surface of this county is almost entirely a smooth plain. The Minooka Ridge touches a few square miles in the northeast corner of the county and the inner slope of the Marseilles moraine touches the extreme noi'thwest and southwest corners. In the eastern jiart there are a fe.w dunes which diversif}' the otherwise monotonous plain. In the lowest part of the basin and along the Illinois River the drift is thin and wells ordinarily enter the rock. On the Minooka Ridge the drift probably averages at least 100 feet and wells have occasionally been sunk beyond that depth without entering rock. On rising toward the ^Marseilles moraine in the western portion of the county there is a corresponding increase in thickness of drift, and rock is not found at less than 100 feet near the western line of the county, except in the trench cut by the Illinois River. The eastern poiidon of the county is covered with sand, which was probably deposited by a lake occupying that portion of the basin. The depth is usually but a few feet and the underlying drift is mainly blue till. The slopes of the Marseilles moraine in the western part of the county, and the Minooka Ridge in the northeastern part, rise above the level of this sand and are composed mainly of blue till to the depth ordinarily reached by wells, 25 to 50 feet or more. The low portion of the county affords a favorable condition for obtain- ingr flowing- wells from the St. Peter sandstone and lower strata, and several such wells have been sunk. A few flowing wells have been obtained from the drift on the slopes of the Marseilles moraine and there is usually suffi- cient hydrostatic pressure to bring the water nearly to tlie surface through- out the county. It is, therefore, highly favored in conditions for obtaining water. WELLS OF KENDALL COUNTY, ILLINOIS. 647 INDIVIDUAL WELLS. At Morris the public water supply is obtained from artesian wells about 600 feet in depth which tei-minate in the St. Peter sandstone. The head is sufficient to raise the water a few feet above the surface. Shallow wells are obtained in the vicinity of this city, at depths of 14 to 30 feet, either in gravel or in sandy shale of the Coal Measures. At Minooka a boring was sunk to a depth of 2,100 feet, which terminated in the Potsdam sandstone. A very strong water vein was struck at about 1,985 feet, with sufficient head to rise 46 feet above the surface, or 660 feet above tide. Although situated on the crest of the ridge, wells are obtained in this village at depths of 30 or 40 feet. At Carbon Hill the public water supply is from an artesian well 1,900 feet in depth, from which water flows direct through the mains.^ At Coal City wells are usually obtained at about 12 feet in the sand which covers that portion of the county. The waterworks are used for fire protection only.^ At Braceville wells are found at the bottom of the sand and also beneath the till at depths of 30 or 40 feet. Rock is entered at Braceville at about 45 feet. At Gardner wells are usually obtained from gravel or sand below till at 40 or 50 feet. Coal shafts enter rock at about 60 feet. Mr. Thomas Cumming, of Gardner, one of the State mine inspectors, reports that water veins of excellent quality are found at several horizons in the Coal Measures in the vicinity of the villages just mentioned.' At Mazon wells are ordinarily obtained at depths of 30 or 40 feet, but several deep wells have been made on farms in that vicinity which do not reach rock at a depth of 100 feet. The drift is mainly a blue till. At Verona, and over an area of several square miles in the vicinity of that village, sandstone is usually entered at about 75 feet. ' Manual of American Waterworks, 1897. ^ Communicated to the writer. 648 THE ILLINOIS GLACIAL LOBE. The following well records include the deepest obtained in the county: Table of wells hi Grundy County. Owner and location. Altitude (above tide). Depth. Kemarks. Feet. Feet. S. Frey, W. part T. 34, K. 6 E . . . 680 190 Drift, mainly till, 140 feet; sandstone, 12 feet; shale, 38 feet. .St. Peter sandstone at bottom. I. Hoge, jr., ,sec. 15, T. 34, R. 6 E 600 58 Flowing well from drift. S. Hoge, sec. 22, T. 34, R. 6 E . . . 600 54 Flowing well from drift. 0. Dix, sec. 8, T. 34, R. 6 E 650 300 Drift, 96 feet; limestone, 100 feet; sandstone, 105 feet. Mr. Morwick, near iireceding.. 650 300 Drift, 100 feet. Section as in preceding. Sees. 23, 24, 25, and 26, T. 34, 575 60 Shale below drift near bottom. E.6E. Sees. 21 and 26, T. 34, R. 6 E . . . 600 125 Rock near bottom. Sees. 15, 16, 21, and 22, T. 34, 575 50 Shale below till at abont 50 feet. R.7E. Sees. 23 and 27, T. 34, R. 7 E . . . 550 24 Wells in sand below till. Sees. 28 and 33, T. 34, E. 7 E . . . 540 30 Shale below till at abont 30 feet. I. Hoge, sec. 31, T. 34, R. 7 E . . . . 550 42 No rock; mainly till. Sees. 12 and 13, T. 34, E. 7 E . . . 550 50 Mainly through sand and gravel. Rock at bottom. Sees. 21 and 22, T. 34, R. 7 E ... 575 45 Drift about 45 feet. Sees. 7 and 18, T. 34, R. 8 E . . . . 550 50 Mainly sand; drift about 50 feet. Sec. 12, T. 33, R. 7 E 510 60 Rock at bottom. Wells in vicinity enter rock at shallower depth. Sec. 23, T. 33, R. 6 E 575 81 Till, 30 feet ; sand, 51 feet. Sec. 24, T. 33, R. 6 E 575 500 113 50 Till, 50 feet ; sand, 63 feet. See. 13, T. 33, R. 6 E Entirely sand. Till, 18 feet ; sand, 102 feet. Sec 22 T 33. R. 6 E 590 120 Sec 21 T. 33 R. 6 E 590 120 Till, 40 ieet ; sand 80 feet. Till, 20 feet; sand 35 feet. Sec.34, T.33, R. 6E 600 55 Sec. 35, T. 33, R. 6 E 600 50 Gravel below till at bottom. WILL COUNTY. GENERAL STATEMENT. Will County is situated on the eastern border of the State, immediate!)- south of Dupage and Cook counties, and has an area of 850 square miles, with Joliet as the county seat. Its northwestern portion is crossed by the broad vallej' of the Des Plaiues, formerly the outlet of Lake Chicago. The extreme western part is traversed in a southward course by the Dupage River. Tlic southwiest corner is crossed in a northwestward direction by WELLS OF WILL COUNTY, ILLINOIS. 649 the Kankakee, which joins the Des Plaines, just west of the county hne, to form the lUinois River. The northwest part of the county and adjacent portions of Dupage and Cook counties are occupied by the Valparaiso morainic system from which drainage hnes lead to the southwest across a much lower region, the altitude of the crest being about 750 to 800 feet, while the plain south- west of it stands but 600 feet in average elevation, and scarcely reaches 675 feet where highest. The extreme western border of the county is occupied by the Minooka till ridge from the north line southward to the head of the Illinois River. Rock is extensively exposed in the southwestern and western parts of the county, but is seldom encountered even in wells in the eastern part. The average distance to rock in 55 wells situated in the low district outside the Valparaiso moraine is 43 feet, which probably represents the approxi- mate average for that portion of the county. Forty-two other wells, sitii- ated mainly along the Valparaiso moraine, though having' an average depth of 76 feet, do not enter rock. The thickness in that portion of the county probably exceeds 100 feet, thoug'h in places rock is near the surface. Along the valleys there are extensive gravel or sand deposits and the southwestern portion of the county is covered with sand dunes. The A^alparaiso moraine and the plain southwest of it have at surface till to a depth of 25 to 50 feet or more, beneath which sand and gravel is often found. The presence of this sand and gravel beneath the till renders this county one especially well favored for an adequate supply of excellent water at shallow depths. Very few wells, aside from deep artesian wells, have been sunk to a depth of 100 feet. INDIVIDUAL WELLS. , The city of Joliet obtains its public water supply from three wells 1,200 feet and one 1,700 feet in depth. The shallower ones terminate in the St. Peter sandstone and the deeper one probably in the Lower Magnesian, though it may reach Potsdam strata. The head is about 40 feet above the surface, or 575 feet above tide. Each well has a capacity of about 500 gallons per minute. The water is moderately hard, but of pleasant taste. The deepest well is cased only 325 feet and its water has a temperature of 45° F. Mr. F. W. Dewey, superintendent of waterworks, reports that the water can be lowered b)' pumping to a depth of 70 feet below the 650 THE ILLINOIS GLACIAL LOBE. surface, aiid tliat wells to a distance of nearly one-half mile are perceptibly lowered by heavy draughts on any one well. Many other ai-tesian wells are made within the limits of the city and the rock strata are drained to about their fullest capacity. A well at the Joliet Steel Mill reaches a depth of 2,076 feet, and one at the State Penitentiary a depth of 1,948 feet, both terminating in Potsdam sandstone. Another well at the penitentiary is but 553 feet in depth and obtains its supply probably from the Gralena limestone. Artesian wells are obtained at Lockport, but no data have been collected. There are also artesian wells at Wilmington and Braidwood, and an artesian well has been sunk on the farm of Judge Caton, about 8 miles west of Joliet. The Braidwood well was made with a diamond drill, and the care- fully presei-ved core formed an interesting exhibit at the World's Fair in Chicago, in 1 893. The depth is 900 feet, but the main supply of water is from a porous sandstone at 655 to 855 feet, the lower 45 feet being in a lime- stone with green shale interbedded. The well formei'ly ovei-flowed, but at present stands near the level of the well mouth (588 feet above tide). The water is slightly sulphurous, but not of unpleasant taste. At Wilmington the best supply of artesian water is obtained at a depth of about 600 to 635 feet, though in some cases strong water veins are struck at 100 feet and several wells obtain water at 250 to 450 feet. The head at these wells is about the same as at Braidwood, slightly below 600 feet above tide. The following table of wells on the Valparaiso niorainic system includes the deepest of which records were obtained. The sections begin near the State line and proceed westward and northward across the county. Wells oil the Valparaiso morainic system in Will County. Owner or loi.'ation. Altitncle (abovetide). "'?*''• Remarks. Feet. Between Goodnow and State 750 line. Endor and vicinity 68.5 .S miles fia.st of Crete - - 725 Crest of moraine smitli of 750 Crete. Crete 720 Feet. 100 Several wells .50 to 100 feet: mainly till; no lock encountered. 75 Drift, mainly till, 75 feet; rock near bottom. 40 Rock entered at 40 feet. 130 No rock etruok. 80 Rock at 80 feet. Many wells from sand at 25 to 40 feet. WELLS OF WILL COUNTY, ILLINOIS. 651 Wells on the Valparaiso niorainic system in Will County — Continued. Owner or location. Altitude (above tide). Depth. Remarks. Feet. Feet. Seo.S, T. 34, R. 14 E T2b 52 Till 23 feet- R.i,Tir1 29 feet Mr. Piepenbrinck, sec. 11 725 106 Gravel below till at bottom. Sec. 1, T. 34, R. 14 E 725 77 No Toclc •^tmpt C.L. Pease, sec. 28 ■ 775 112 No rock, mainly bine till. Beecher (east part) 720 106 No rock, mainly blue till. Old soil beneath glacial gravel at 50 feet. 2 miles east of Beecher 725 50 Monee antl vicinity 800 50 Wells in sand below till n,t 40 fn nO fppt One-half milo north of Monee. 800 180 Mainly blue till. Sec. 4, T. 34, R. 13 E 775 70 Till. 50 feet- sand 20 feet Sec. 10, T. 34, R. 13 E 800 92 No rock, mainly blue till. Several wells. Sec. 12, T. 34, R. 13 E 750 65 Three wells, similar: Till, 55 feet; sand, 10 feet; no rock. Peotoiie and vicinity 725 60 Wells, 40 to 60 feet, mainly till ; no rock. Similar to preceding. North part T. 33, R. 12 E 675 60 Sec. 26, T. 34, R. 12 E 725 55 No rock, mainly till. No rock, mainly till. Drift exceeds 100 feet In several wells. Sec. 36, T. 34, R. 12 E 725 50 Morainic crest, T. 34, R. 12 E . . 7.50 100 Morainic crest, T. 35, R. 12 E . . 750 100 Wells through till ; no rock. A. Reid, sec. 13, T. 35, E. 12 E. . 710 10 Rock entered at 10 feet. Frankfort 758 90 Wells 70 to 90 feet, mainly till; no rock. No rock struck. Mr. Baumgartner, 1 mile 760 135 southwest of Frankfort. Spencer, at Elevator 711 75 Mainlv till - sand at bottom Sec.8, T. 35, R. 11 E 630 48 A.^tv.xi V vm , .3Cl'iiVX turn UUI/UulXl. Yellow till, 15 feet; sand, 15 feet; yellow till, 18 feet. Sec. 18, T. 35^ R. 11 E 650 60 Cemented gravel below blue till near bottom. New Lenox and vicinity 630 33 AVells in valley enter rock at 7 to 33 feet. Sec. 35, T. 35, R. 11 E 720 82 Yellow clay, 8 feet ; gravel, 14 feet ; blue till, 60 feet. Drift, mainly till, 95 feet; limestone, 13 feet. No rock; mainly till. Sec.9, T.36, R. 11 E 750 108 Sec. 12, T. 36, R. HE 710 104 Sec. 12, T.36, R. HE 720 114 No rock; mainly till. No rock; mainly till. Till, 68 feet; gravel, 12 feet. Till, 50 feet; sand, 12 feet. Sec. 13, T. 36, R. 11 E 700 115 Sec. 32, T. 36, R. n E 675 80 Des Plaines bluff, eastof Romeo 640 62 Sees. 9, 10, 11, and 12, T. 37, 725 60 In cemented gravel below till. E. 10 E. Sec. 11, T. 37, E. 10 E 700 96 No rock struck. Mr. Godfrey, sec. 13 760 160 Till, 100 feet; gravel, 10 feet; sand, 40 feet; lime- stone, 10 feet. Mr. Gowdy, near Dupage post- 650 50 Rock in one well at 35 feet; none in another at 50 office. feet. 652 THE ILLINOIS GLAOIAL LOBE. The following table serves to illustrate the depth and character of di-ift in the deep wells in the portion of the county outside the Valparaiso system : Welln in Will County outside the Valiiaraiso morainic system. O^^Tier or location. Altitude (above tide). Depth. Remarks. Feet. Feet. West border T. 37, R. 9 E T2o 130 Wells on Minooka Ridge penetrate till 80 feet, be- neath which is sand extending to rock at about 130 feet. East half ofT.37, E.9E 650 20 AVells usually enter rock at about 20 feet; drift gravelly. T 35 R 9E 620 30 Gravelly drift between Dupage and Des Plaines River; wells at about 30 feet. i t t^nj^ ^M.%it f -»j -•■• .•••« ---- A*** -to County Infirmary, T. 35, R. 9 E. 620 40 Mainly through gravel. Sec. 36, T. 35. R. 9 E 575 45 Till "with thin sand beds. Sec. 7, T. 34, R. 10 E 600 80 Flowing -well, mainly till. Thought not to enter rock. Sec. 25, T. 34, R. 9 E 630 60 Yellow till, 20 feet; blue till, 40 feet; limestone, 6 feet. Joliet Mound, se.'. 19, T. 35, 560 60 Cobble and gravel, 45 feet; clay, 15 feet; limestone R. IDE. at Ijottom. NE. corner T. 3.5, R. 10 E 675 110 Wells 90 to 110 feet; mainly till; no rock. El wood tile factory 640 70 Till, with thin beds of gravel. Xeighboriug wells enter rock at 50 feet. Sec. 13, T. 34, R. 10 P: 650 - 630 32 28 Till to rock, at 32 feet. Sec. 14, T. 34, R. 10 E Drift, mainly till; rock at 28 feet. Sec. 20, T. 34, K. 10 E 630 75 Mainly till; rock at 75 feet. Sec. 24, T. 34, R. 10 E 630 650 650 38 32 58 Till, 20 feet; sand, 9 feet; till to rock (9 feet). Till, 17 feet; sand, 5 feet; till to rock (10 feet). Rook at bottom. Sec. 26, T. 34, R. 10 E Sec. 32, T. 34, R. 10 E Sec. 34, T. 34, R. 10 E 660 35 Mainly till; rock at bottom. Sec. 21, T. 33, R. 10 E 600 640 90 50 Drift, mainly till, 49 feet; limestone. 41 feet. Sec. 6, T. 33, R. 10 E Mainly till; rock at bottom. Yellow till, 12 feet; blue till, 40 feet; no rock. Sec. 16, T. 33, R. 10 E 660 52 Sec. 34, T. .S3, K. 9 E 560 31 Till, 13 feet; sand, 18 feet. Wilmington ;ind vicinity 560 40 AVells 20 to 40 feet, from gravel. Braidwood 1 590 40 Wells 18 to 40 feet; sand, 15 or 20 feet; blue clay, 20 or 25 feet. 2 miles east of Braidwood 590 220 Sand, 20 feet; blue clay, 20 feet; remainder rock, 180 feet. 1 WELLS OF KANKAKEE COUNTY, ILLINOIS. 653 KANKAKEE COUNTY. GENERAL STATEMENT. This county is situated on the eastern /border of the State immediately south of Will County, and has an area of 680 square miles, with Kankakee as the county seat. The Kankakee River leads westward tlu-ough its cen- tral portion. The greater portion of the county is imperfectly drained, there being- extensive marshes and sandy areas in the southeastern part, and a very level surface in the western, while the northern portion is character- ized by occasional sloughs and marshes. The drift is a comparatively thin deposit along the Kankakee River and its borders tln-oughout the county, but the western, southern, and northeastern portions of the county have a sheet of drift probably not less than 100 feet in average thickness. In the vicinity of the Kankakee the drift consists mainly of gravel or sand, but in its thicker portions on the borders of the county there is generally present a heavy sheet of till. The wells are of moderate depth throughout the county, there being- very few which reach 100 feet, even in the portions where it is necessary to di'ill into rock. INDIVIDUAL WELLS. The public water supply for the city of Kankakee is pumped from the Kankakee River, but there are numerous drilled wells in the city 30 to 90 feet in depth. A small till ridge leading eastward from the vicinity of the court-house aifords water at depths of 20 to 60 feet without entering rock. Throughout much of the city, however, rock is found at a depth of 10 feet or less. A well sunk on the south side of the Kankakee opposite the city reached a depth of 1,000 feet, entering- St. Peter sandstone at 900 feet. The water rises within 15 feet of the surface, or to about 605 feet above tide. At Momence the wells are obtained in limestone at a depth of 12 to 80 feet. A strong well can usually be obtained at a depth of 30 feet. The wells are generally about 5 inches in diameter and are reported to be practically inexhaustible. In the southeast township of the county several flowing wells have been obtained from sand below a gray clay at depths ranging from 30 to 654 THE ILLINOIS GLACIAL LOBE. 90 feet. In some cases water fails to reach the surface, choug-h all the wells m that locality have strong hydrostatic pressure. At St. Anue a few of the wells reach a depth of 80 feet, entering rock at about 60 feet. At Sherburnville, on the east border of the countv, wells frequently reach a depth of 60 feet without entering rock. They peneti-ate 25 or 30 feet of till, beneath which is sand. Much of T. 32, R. 14 E., which is situ- ated west from Sherburn^^lle, has wells of similar depth and structui-e, but in the northeast part of T. 32, R. 13 E., rock is often struck at a dei^th of 30 or 40 feet. In the vicinity of St. George, in the northern part of the countv, wells usually enter rock at a depth of 10 or 20 feet. This thin drift characterizes much of northern Kankakee County westward beyond Manteno. In a few places in the west part of T. 32, R. 14 E., and in T. 32, R. 13 E., well di-iUers repoi't having passed tlu-ough an old soil below the blue till near the base of the drift. At Deselm post-office, in the northwest part of the counts', there is a drift ridge in which the distance to rock is about 60 feet, the level being about the same beneath the ridge as on the bordering plain. In the south- west part of the county on the border of the Marseilles moraine records of 6 wells were obtained which reach rock at a depth of 100 to 162 feet. The altitude is about 700 feet above tide, or nearly 100 feet above the Kanka- kee River at the city of Kankakee. The rock surface is therefore not much lower than at Kankakee. In the vicinity of Irwin and Dickev and Her- sher rock is usually entered at 40 to 60 feet, but at Buckingham the drift is about 90 feet in depth. Two flowing wells have been obtained at Dickey from beds of gravel and sand at the base of the di-ift. The underlying rock is shale. From Union Hill eastward to Kankakee the drift is generally of slight depth, but from this village westward to the county line its tliickuess is 50 to 100 feet or more. IROQUOIS COUNTY. GENERAL, STATEJIENT. Iroquois Count}- is situated south of Kankakee ou the east border of the State, and has an area of 1,120 square miles, being exceeded in size WELLS OF IROQUOIS COUNTY, ILLINOIS. 655 oiily by McLean and Lasalle counties. Watseka, the county seat, is sit- uated a few miles east of tlie g-eog-vapliic center. The Iroquois River enters the county from Indiana in the northeast part, and after "passing westward to Watseka it turns northward and enters the Kankakee a short distance north of the county Hne. This stream, with its tributaries, drains almost the entire county. It is a widely-branching drainage system, yet the num- ber of di'ainage lines is too few to afford escape for the surplus rainfall, and there are extensive marshes within its drainage basin. The county is mostly occupied by a basin whose borders lie not far beyond the county limits. On the west and south this basin is limited by the prominent Bloomington morainic system; on the north the basin is limited by the Marseilles moraine, which follows nearly the line of Iroquois and Kankakee counties; on the east it finds a natural limit in the Iroquois moraine, which traverses the eastern portion of the county. This basin is due entirely to di-ift aggregation, for the underlying rock apparently stands higher in the low part of the basin in the northern portion of the county than in the rim of the basin on the west and south. This basin is found to be a favorable locality for obtaining flowing- wells from the di'ift, and several hundred have already been made, which have been discussed by the writer in the Seventeenth Annual Rejjort of this Survey. There is a perceptible increase of head in passing from north to south. There is an increase also in passing from near Watseka either east- ward or westward. There is little doubt, therefore, that the absorbing- areas are found on the east, south, and west borders of the basin. This is contrary to the interpretation made by the residents, who quite generally suppose the supply to be derived from the Kankakee marsh on the north- east, a marsh whose altitude is in the main below the level of the lawer parts of this basin. The drift is largely a soft till to a depth of 76 or 100 feet, though in the northeastern part of the county there is a surface sand a few feet in depth capping the till and which connects with the sand of Kankakee County mentioned above. The till is found to be underlain at many points hj a black soil and by beds of peat and shell marl. With the peat and marl there is usually considerable sand, which is a source for the flowing wells. After these beds of peat and sand are jjenetrated a harder till is entered than the surface sheet. In some cases this till is found to include 656 THE ILLINOIS GLACIAL LOBE. beds of peaty soil and sand which afford water for the flowing- wells. In one case, near the south border of the countv, a buried peat was found to have a depth of 30 feet, showing that a long interval must have elapsed between the deposition of the sheets of drift which it separates. The time • need be no longer than has elapsed since the upper till sheet was deposited, for in that same locality there is an instance of the penetration of peat to a depth of 32 feet; there being a kettle-hole with an area of 5 acres which has peat of this thickness, as shown by a series of test borings made bv Dr. Luddeu, of East Lynn. The thick deposit of bui'ied peat just refen-ed to occurs in the midst of the hard tills and not at the junction of the soft till with the hard till, there being 26 feet of hard brown till above the peat, which in tui-n is overlain by 80 feet of soft till of the Wisconsin stage. INDITIDUAJL WELLS. At St. Mary's, in the northeast pait of the county, wells are usually obtained at about 40 feet. One well in the village, however, was sunk to a depth of 140 feet without entering rock ; it passed thi-ough an old soil at 80 feet, and water from the lower portion of the well rose within 18 feet of the surface. Thi'ee wells about a mile west of St. Mary's, at an altitude perhaps 20 feet lower, enter rock at 90 to 100 feet. The di-ift is mainly till, and water rises within 20 feet of the sui-face, or to about 630 feet above tide. East from St. Marv's several wells enter rock at about 100 feet, thoug-h occasionallv a greater amount of drift is penetrated. For instance, in sec. 11, T. 28, R. 11 W., a well 176 feet in depth enters rock at 135 feet. The di'ift is mainly blue till. Water rises from the rock to within 15 feet of the surface. At the village of Papineau wells enter rock at 40 to 45 feet and water rises within 5 feet of the smiace. In the valley of Beaver Creek, north of tliis village, at an elevation about 15 feet lower, several flowing wells have been obtained, some being from the drift, others from the rock. In the vicinity of Martinton rock is entered at about 60 feet. A well 1 mile north of this village, 276 feet in depth, penetrates drift, raainlv till, 60 or 65 feet; shale, 15 feet; mainly limestone, 196 feet. The water level is 10 feet below the surface, or 620 feet above tide. At Pittwood several weUs have been sunk to a depth of 100 to 130 WELLS OF IROQUOIS COUNTY, ILLINOIS. 657 feet without reaching rock. Wood is found occasionally near the bottom. Water rises within 15 feet of surface or to about 630 feet above tide. Three miles northwest of this village, in sec. 26, T. 28, R. 13 W., a well penetrates till sheets of different hardness. The iipper 45 feet is a soft till, the remainder a hard till. The bed of sand at bottom furnishes water which rises within 3 feet of the surface. In the adjoining section on the south (sec. 35) a well 156 feet in depth does not reach rock. Water rises just to the surface. In sec. 29 of this township a well penetrated an old soil near the base of the drift at a depth of about 95 feet. Wells in that vicinity enter shale at about 100 feet and limestone at about 160 feet. In the north part of the county, near Chebanse, rock is entered at 80 to 100 feet. About 3 miles east of the village on the farm of 0. Sykes, and also on neighboring farms, wells were noted in which beds of peat 20 feet in thickness were found near the base of the drift at depths of 60 to 80 feet. In the vicinity of Ashkum wells usually enter rock at about 80 feet, though one half a mile west of the village reached a depth of 146 feet before striking rock. There is usually a soft till about 50 feet, beneath which is a harder till, associated in places with sand beds. The water level from wells obtained in the lower part of the drift and upper part of the rock is 10 to 20 feet below the surface, or about 640 feet above tide. Along the border of Langum Creek Valley, in the vicinity of Ashkum, wells enter limestone at 60 to 90 feet. In some cases they obtain water in sand below till at 40 to 60 feet. The water usually rises within 5 or 10 feet of the surface. A well at Mr. Mayo's, about 5 miles northwest of Ashkum, pene- trated 120 feet of drift containing a log near the bottom, and terminated in shale at 167 feet. Water stands within 4 feet of the sui-face, the altitude being slightly lower than at Ashkum. About 3 miles west from this well the records of three wells were obtained which obtain water in limestone at 60 to 68 feet. The head is sufficient to bring the water barely to the surface. In the vicinity of Prairie Creek, southeast from Ashkum, a few flowing wells have been obtained'from the drift at depths of 75 feet or less. At Danforth wells from the drift 100 feet in depth have a head about 7 feet below the surface or about 640 feet above tide. The last edition of the Manual of American Waterworks reports a deep well in progress, but MON xxxviu 42 658 THE ILLINOIS GLACIAL LOBE. no good supply had been obtained though sunk to a depth of 1,200 feet. Near this village, at Mr. Eden's, a well 168 feet in depth peneti-ates — • Section of Eden well near Danforth, Illinois. Feet. Soft till 70 Hard till 60 Shale 38 It obtains water in limestone at bottom. A neighboring well obtains water at 72 feet, in sand below a soft till. Wood was found just above the water vein. At La Hogue several flowing wells have been obtained from the drift at depths of 70 or 80 feet. They are mainly throiigh soft blue till. Flowing wells are found at a similar depth at Ridgeville and in the interval between these two villages. Occasionally a well only 40 or 45 feet in depth has sufficient head to nearly reach the surface. At Gilman flowing wells are obtained from the drift at depths of 75 to 150 feet. It is designed to use such wells for a p^^blic water supply. Occasionally wells are sunk to the imderlying rock, which is reached at 190 or 200 feet. The shallow wells in Oilman are obtained at 12 to 16 feet. At Onarga several wells have been sunk to a depth of 90 to 160 feet from which water rises within 10 or 15 feet of the surface, or to about 660 feet above tide. The public supply is from three wells of this class.^ In a portion of this village there is sm-face sand to a depth of 12 to 18 feet, at the bottom of which wells are often obtained. The following three bor- ings are reported in the geology of Illinois. A coal boring near Onarga is thought to have reached a depth of 400 feet without encountering rock, though it terminated at an elevation but 260 feet above tide, or about the level of the Mississippi River at Cairo. The reliability of this record appears questionable, it being given from memory some years after the boring was made. A boring between Onarga and Oilman is reported to have reached rock, thought to be Lockport (Niagara) limestone, at 268 feet, the drift section being as follows : Section of a horinq betioeen Onarga and Gilman, Illinois. Feet. Blue and red clay 98 Sand and soft sediment 1*0 Hardpan ^0 Hard stony clay -^0 Total 268 ' Manual of American Waterworks, 1897. WELLS OP lEOQUOIS COUNTY, ILLINOIS. 659 At Onarga a coal boring readied the first rock at about 300 feet. The rock was interpreted to be Hudson River (Cincinnati) shale.^ In the vicinity of Crescent many flowing wells have been obtained at depths of 80 to 120 feet. There is scarcely a section in the south half of T. 27, R. 13 W., or any part of T. 26, R. 13 W., in which the water does not overflow or rise within 10 feet of the surface. The public water supply at Crescent is from four wells of this class.^ Many wells south of Crescent pass thi'ough an old soil at depths varying in the different wells from 60 to 80 feet below the surface. Above the soil the till is not nearly so hard as that below. At Watseka many flowing wells have been obtained from the drift at depths of 100 to 150 feet, and the first rock is encountered at about 165 feet. The public water supply is from a well 150 feet in depth, which has sufficient capacity to supply the city. In the higher portions of the city the water falls short a few feet of reaching the surface. The mayor reports that no shallow wells are in use and that few wells are obtained at less depth than 85 feet. The surface is coated to a depth of a few feet with sand, beneath which there is a soft blue till extending to a depth of 85 or 100 feet. Beneath this a hard till with alternating sand beds is penetrated. Along the Iroquois Valley above Watseka in this county, and also in Newton County, Indiana, flowing wells are obtained from the drift at depths of 70 to 120 feet. A well at the village of Iroquois, 88 feet in depth, is reported to have passed through a black soil below blue till near the bottom. North of the Iroquois Valley, on the Iroquois moraine, in the vicinity of Donovan, several deep borings have been made which enter rock at depths of 125 to 170 feet and obtain their supply from limestone at 200 feet or less. The water in that locality rises within about 40 feet of the surface, or 635 feet above tide, which is nearly the altitude in neighboring lower districts to the north and west. These deep wells in several instances encounter an old soil at about 140 feet. Hard till sets in at about 100 feet- No instance of the occurrence of a soil at the top of the hard till was reported, though it is often present in the neighboring districts, as already noted. Soiith of the Iroquois River, in the vicinity of Sheldon, the drift has a thickness of 100 to 120 feet and is mainly a blue till. On the moraine 'Geol. of niinois, Vol. IV, pp. 237-238. ^^jiauual of American Waterworks, 1897. 660 THE ILLINOIS GLACIAL LOBE. south of this village, iu sec. 11, T. 26, R. 12 W., a well 156 feet in depth entered rock uear the bottom and struck a bed of coal. Two other borings located in the north part of T. 25, R. 11 W., enter rock and strike coal at only* 60 feet. Several other wells in that locality reach a depth of 160 feet without entering rock. They penetrate about 80 feet of soft till, beneath which is a hard till, in which little sand is found at less than 160 feet from the sui'face. Along Sugar Creek Valley, north of Milford, thi-ee wells were noted which strike an inflammable gas in sand below till at a depth of 40 feet. In the vicinity of Milford wells are usually obtained at depths of 40 to 60 feet, and water does not rise usually within less than 25 feet of the surface, or to about 645 feet above tide. The public supply is from two 8-inch wells 60 feet deep.^ A boring at Milford in search of coal has the following section : Section of a coal boring at Milford, Illinois. Feet. Soft till 45 to 50 Hard till, with some sand beds 70 Shale 88 Limestone at bottom Total -- 208 West from Milford, for 6 or 8 miles, several wells have been sunk to depths of 100 to 110 feet, which obtain water in sand below the blue till. Its head is 20 feet or more below the surface. In the southeast part of Iroquois County a black soil has been found in a few wells at about 160 feet. These wells penetrate 90 or 100 feet of soft till and 50 feet or more of hard till before entering the soil. At Wellington, wells are often obtained at a depth of 70 feet, which have a head about 20 feet below the surface, or 680 feet above tide. They are said to enter a hard till in the lower 10 or 15 feet. At Clayton flowing wells are obtained at a depth of 60 or 70 feet and also at about 100 feet. The deeper ones penetrate an old soil near the bottom. The head at these wells is about 675 feet above tide. Four miles south of Clayton, in sec. 27, T. 24, R. 13 W., two flowing wells have been obtained, one at 50 feet, the other at 80 feet, whose head is nearly 700 feet above tide. A mile farther south is the well noted above, Avhich penetrated ' Manual of American Wiiterworks, 1897. WELLS OF lEOQfTOIS COUNTY, ILLINOIS. G(3l a buried peat 30 feet in thickness. It is on the farm of Dr. Ludden, in sec. 33, T. 24, R. 13 W. The following is the section furnished by Dr. Ludden: Section of Ludden well, ~> mile.i south of Clayton, Illinois. Feet. Mainly blue till 80 Hard brown till 25 Peat : 30 Coarse sand 9 Total 144 At Cissna Park the public water supply is from a flowing well, the water being pumped from the receiving reservoir to the standpipe.^ North from Clayton, in the vicinity of Ash Grove, many flowing wells are obtained at a depth of about 100 feet. They penetrate alternations of sand and soft blue till to a depth of 55 or 60 feet, below which a hard gray till is entered with which thin beds of gravel, yielding water, are associated. Several wells are reported to pass through a soil containing wood at a depth of about 100 feet, or some distance below the top of the hard till. In the Ash Grove timber belt wells are occasionally sunk to a depth of 160 feet and penetrate a section similar to the preceding, passing through soil and wood at 95 or 100 feet, beneath which are alternations of hard till and sand. Occasionally a well passes through a heavy deposit of gravel or sand beneath the soft till, but usually the sand and gravel beds are thin. In a low tract known as Shavetail Slough, in the northeast part of T. 25, R. 13 W., several wells have been sunk to a depth of about 160 feet, which penetrate a black soil below hard till at 160 to 158 feet, and obtain water in sand at bottom. The head is sufficient to barely reach the surface. In the vicinity of Buckley, and thence southeast to Cissna Park, flow- ing wells are frequently obtained at depths of but 50 feet, in sand or gravel below a soft blue till. At Buckley the water rises within 8 to 16 feet of the top, but on low ground west of the village a few wells overflow at an alti- tude about 690 feet above tide. The public supply is from a flowing well.^ In the vicinity of Thawville flowing wells are obtained only on the lowest ground at an altitude about 685 feet above tide. They frequently reach a depth of 135 or 140 feet, and pass through a black soil containing wood near the bottom. ' Mann al of American Waterworks, 1897. 662 THE ILLINOIS GLACIAL LOBE. In the -sdcinity of Loda wells are often sunk to a depth of 100 feet, mainly through till. The water rises as in the flowing well district, but the altitude is much too high for an overflow, being about 775 feet above tide. FORD COUNTY. GENERAL STATEMENT. Ford County is situated west of Iroquois and also extends a short distance along- the western portion of the south border of that county. It is a naiTow tract, its northern two-thnds being but 6 miles in width. It has an area of 490 square miles and Paxton is the county seat. It occupies a comparatively elevated tract from which streams discharge in all directions. From the northern portion the drainage is in part tributary to Mazon Creek, which enters the Illuiois at Morris ; ia part to the Illinois- Vermilion River, which enters the Illinois at Lasalle, and in part to the Iroquois River. The southern portion divides its waters between the Iroquois, the Wabash- Vermilion, and the Sangamon rivers. The southern half of the county is occupied by the Bloomington morainic system, whose highest points have an altitude about 860 feet above tide. The exti-eme northern end is occupied by the Marseilles system. Between these morainic systems there is a plane tract which constitutes the westward extension of the basin of Iroquois County, and like it is favorably situated for obtaining flowing wells. Its altitude is 650 to 700 feet. The entire county is covered with a nearly continuous sheet of blue till 100 feet or more in average depth, beneath which there is apparently a series of hard till deposits interbedded with sand and gravel, similar to those in Iroquois County ah-eady discussed. Records of eight wells which reach the rock show an average thickness of 211 feet of drift, which is perhaps a fair approximation to the average for the county. Many deep tubular wells have been sunk in this county, some of them reaching depths of over 200 feet without entering rock. The gi-eatest thickness reported within the county is at the artesian well in Paxton, where 440 feet of drift was penetrated. INDIVIDUAL WELLS. The public water supply at Paxton is from wells about 150 feet in depth, obtained in sand and gravel below a sheet of till. The water rises WELLS OF FORD (JOUNTY, ILLINOIS. 663 about 100 feet and is practically inexhaustible. The artesian well at this city, referred to above, has a depth of 2,670 feet, but no further data con- cerning it have been obtained. At Gribson the public water supply is obtained from three wells 55 feet in depth and 7 inches in diameter. Many private wells are obtained at 12 to 25 feet, thoug-h a few are 46 to 55 feet. They are largely through sand and gravel, the town being situated on a plain just outside the Bloom- ington morainic system, which apparently received a coating of sand and gravel as a morainic outwash. A boring for coal at this city was sunk to a depth of 705 feet and penetrated 175 feet of drift. The following table of sections of deep wells is begun at the northern end of the county and proceeds southwai'd. It includes the deepest of which records were obtained: Deep wells in Ford County. Owner or location. Altitude (above tide). Depth. Remarks. Feet. 706 706 737 737 750 700 680 650 650 650 650 678 650 650 Feet. 240 200 176 185 196 203 75 75 23 20 65 95 165 Depth given by Man. Amer. Waterworks, 1897. Thin beds of shale and coal overlying limestone, entered at about 200 feet, at base of drift. Reported in Manual of American Waterworks that public water supply is from a well. Drift mainly till; rock at about 175 feet. Rock struck at bottom ; drift mainly till. Enters rock at bottom Kempton, village well Kempton, several wells Sec. 33, T. 29, E. 9 E Sec 24 T 29 R. 9 E Sec. 11, T. 28, R. 9 E Vermilion S"wanit) ...... Drift, 150 feet ; shale with two coal beds, 53 feet. Flowing wells from sand below till. Flowing wells from sand below till Sec 5 T. 27, R. 9 E Sec 9 T.26, R. 9 E Three flowing wells 20 to 23 feet in depth. Several flowing wells from drift at about 20 feet. Flowing wells at about 65 feet; five water reins penetrated; in sand between tills. Sees. 10, 13, and 14,T. 26, E. 9 E. Sec. 22, T. 27, R. 9 E Sec 17.T.27. R. 9E feet; soft blue till, 30 or 40 feet; hard blue till, 25 or 30 feet; black muck, 20 feet; sand and gravel at bottom. Harder till in lower than in upper half; limestone near bottom. East part Ts. 26 and 27, R. 9 E . ( 675 1 700 60 80 Several flowing wells at 60 to 80 feet. Sec. 31, T. 26, E. 9 E 800 240 Soft till, 130 feet; harder sandv drift 110 feet; no rock. 664 THE ILLINOIS GLACIAL LOBE. I>eep icells in Ford County — Ooutiiiued. Owner or location. Altitude (above tide) . Depth. Remarks. Sec. 7, T. 25, R. 9 E . Sec.7,'T.25, R.9E , Roberts No. 1 . Roberts No.2- Seo. 25, T. 25, E. 8 E . li miles southeast of Sibley. . Melvin Sec. 2, T. 24, R.9E Sec. 11,T.24, R. 9E Sec. 36, T. 24, R. 9E Northwest part T. 24, R. 9 E . . . Near Henderson Station Seo.28,T.23, R. 10 E Tile factory in Ten-Mile Grove. Paxton and vicinity. Kirk Station Between Paxton and Kirk... Sec. 29, T. 23, R. 14 W Feet. 800 800 780 780 800 775 761 775 750 Feet. 237 196 200 117 240 825 240 808 140 775 200 775 201 800 115 750 117 775 80 750 155 750 73 150 140 175 116 Soft till, 1 Ofeet; sand, 20 feet; blue clay, 20 feet; cemented sand and gravel at bottom. Yellow till, 8 feet; sand and gravel, 40 feet; blue till with thin sand beds, 95 feet; reddish till, 10 feet; brown till, 26 feet; sand at bottom, 10 feet. No rock ; log at about 100 feet. Blue till, 91 feet; hard gray till, 24 feet; sand at bottom. Mainly blue till, 125 feet ; black sand, 6 or 8 feet ; blue till, 80 or 85 feet; sand, 20 feet. No rock or water; mainly blue till. Wells 115 to 140 feet; hard till near bottom. Till, 120 feet; sand, 80 feet. Yellow till, 16 or 18 feet; blue till, 70 or 75 feet; blue sand, 85 feet ; black soil. 2 feet ; brown sandy clay, 11 feet; sand, 5 feet. No rock struck. Wells 110 to 117 feet through till. Much sand and grax'el in wells 80 feet in depth. Mainly blue till ; sand at bottom. Yellow clay, 10 or 12 feet; gravel, 6 feet; blue clay, 12 or 14 feet; blue clayey sand, 18 feet; sand, 25 feet. Strong wells at 100 to 150 feet in sand below till. Inflammable gas in several wells. Mainly blue till, 98 feet; sand, 42 feet. Wells 100 to 175 feet penetrate 80 or 100 feet of till, then saud and gravel to bottom. Alternations of sand and till. LIVINGSTON COUNTY. GENERAL STATEMENT. Livingston County is situated west of Ford and Kankakee counties, its western border reaching nearly. tlie middle of the State. It has an area of 1,026 square miles, and Pontiac is the county seat. Vermilion River traverses the county from southeast to northwest nearly centrally. Its tributaries are almost entirely on the western side of the stream, the eastern side being occupied by the Marseilles moraiiiic system and an earlier WELLS OF LIVINGSTON COUNTY, ILLINOIS. 665 moraine (Chalsworth-Cayuga Ridge) classed in the Bloomington system. The northeast part of the county drains northward tlii'ough Mazon Creek. Aside from the moraines just referred to, which traverse the central portion of the county in a northwest to southeast course, and which occupy a belt with an average width of about 10 miles, the surface of the county is very flat. Nearly all the streams of the county flow in mere ditches channeled to a level but a few feet below the plains. With the exception of a narrow strip along Vermilion River from near Fairbury to Sti'eator, where rock is frequently exposed, the count}^ has a heavy deposit of drift averaging possibly 150 feet in thickness. There appear to be buried valleys traversing the county whose rock floors are 150 to 200 feet below the general level of the rock surface. In such valleys the drift is over 300 feet in thickness. On the borders of Ver- milion River nearly all of the thin sheet of drift is sand and gravel. With this exception the county is generallv covered with a tliick sheet of blue till, which is oxidized for a few feet at the surface. On the Marseilles moraine in this county a blue till is found at less depth than at any other points noted in the State, in places within 2 or 3 feet of the surface, there being very little yellow or oxidized till. Usually the yellow till is 6 to 10 feet in depth both on this moraine and later ones. Neai'ly all the well sections obtained in this county are located in the northeast one-half, the southwest part having- been covered only by a hasty reconnaissance. Along the Marseilles moraine and also on the plain to the northeast wells are frequently sunk to a depth of 100 feet en- more, and better supplies appear to occur at that depth than nearer the smface. INDIVIDUAL WELLS. The public water supply at the city of Dwight is obtained from two wells sunk to a depth of 135 feet in the glacial drift. The water rises within 5 feet of the surface. A boring for coal at this town' entered shale at about 100 feet. The record of a private well in the northeast part of the town is as follows: Section of well at Dwif/ht, Illinois. Feet. Yellow till 17 Blue till 83 Hard yellow till 17 Total , 117 Sand at bottom from which water rises within 5 or 6 feet of surface. 666 THE ILLINOIS GLACIAL LOBE. At Odell wells are obtained at 30 or 40 feet. The di-ift varies greatly in thickness within the limits of this village. A well at the Chicago and Alton Railway station entered rock after penetrating 138 feet of till; another, on the Spencer farm near the western limits of the town, entered rock at 168 feet, but a boi'ing made by Mr. Matteson in the South part of the town penetrated 360 feet of di'ift. An experimental gas boring about 3^ miles soutliAvest of Odell penetrated 300 feet of drift. The deep drift at Mr. Matteson's well in OdeU is mainly till to a deptk of 200 feet, beneath which is sand. At Nevada wells are usually obtained at 30 or 40 feet, but records of two borings were collected which failed to obtain water at a depth of 100 feet. They are mainly through blue till. At Cornell and in its vicinity wells are obtained at about 20 feet in sand and gravel, the ^^llage being located on the low gravelly plain bor- dering Vermilion River. At Pontiac wells frequently enter limestone at a depth of 10 to 25 feet and obtain water at comparatively shallow depths. The public supply is pumped from Vermilion River. ^ An area of sandy drift extends several miles south of this city and wells are there obtained at shallow depth with- out entering rock. At Fairbury the public water supply is from a well 2,002 feet in depth, from which water rises within 60 feet of the surface. The well is cased about 365 feet. Wells are usually obtained in that vicinity at about 25 feet in a gravelly drift. Coal shafts in the vicinity enter rock at 50 to 90 feet. At Forest strong wells are obtained at 25 or 30 feet and juauy wells are only 10 or 12 feet in depth. Coal shafts and other borings in the vicinity show the drift to be about 150 feet in thickness and largely till in the lower part. At Chatsworth the public water supply is from a well sunk to a depth of 67 feet in the glacial drift, mainly through till. Several wells in this village are about 50 feet in depth, and a few are 80 feet, without entering- rock. Two coal borings reported in the Geology of Illinois show much difference in the distance to rock. One in the southeast part of sec. 4 enters rock at 84 feet, while another, one mile east, at about the same ele- ' Manual of American Waterworks, 1897. WELLS OF LIVINGSTOJf COUNTY, ILLINOIS. 667 vation, struck rock at 221 feet.^ The latter boring' had hard till in the lower part of the drift, while the former passed through a "dirt bed with wood" just before entering rock. In the vicinity of Risk and Strawn, in the south part of the county, there is about 90 feet of drift as determined by coal borings, but wells are usually obtained at 50 feet or less in sand below till. The public supply at Flanagan is reported by the Manual of American Waterworks to be from an artesian well, but no data are given as to depth or head. Coal borings made at the villages of Cullom, Saunemin, and Campus, in the east part of the county, penetrate 171, 162, and 125 feet of drift, respectively, but wells at these villages are obtained at moderate depths, seldom exceeding 40 feet in sand or gravel below till. The Manual of American Waterworks reports that Campus obtains its public water supply from a driven well. In some places water is very difficult to obtain at moderate depths; thus, at the village of Grriswold, several borings have been sunk to a depth of 75 feet without obtaining strong wells. Outside the villages just discussed only a few records of wells have been obtained, and these include the deepest of which the wi'iter has obtained information : Wells in Livingston County. Owner or location. Sec. 1, T. 30, R. 5 E Sec. 12, T. 30, E. 5 E Sec. 18, T. 30, E. 5 E Mr. Adams, at Blackstone Mr. Budd, at Budd Station Sec. 14, T. 29, E. 5 E Northeast part T. 39, E. 5 E . . . . Sec. 25, T. 29, E. 5 E Sec.27,T.29,E.5E Sec.33,T.29, E.6E Cayuga 4 miles south of Odell Altitude (above tide). Depth. Remarks. Feet. Feet. 700 216 Eock entered at about 200 feet. 700 135 Water from sand below blue till. 750 80 Mainly till; no rock. 733 200 Rock entered at 160 feet; drift mainly till. 702 160 Enters rock at 160 feet. 700 130 Mainly till; no rock. 700 100 Several wells 70 to 100 feet, from sand below till. 650 130 Flowing well from sand below till. 650 78 Several wells 60 to 78 feet; from sand below till. 700 60 Flowing well from sand below till. 685 100 Eock.at 100 feet; drift mainly tiU. 700 68 Flowing well from sand below till. Geology of Illinois, Vol. VI, pp. 243, 244. 668 THE ILLINOIS GLACIAL LOBE. Wells in lAvingston County — Continued. Owner or location. Altitude (abovetide). Depth. Eeniarka. Sec. 33. T. 29, R. 7 E Feet. 725 700 675 675 650 . 650 700 760 700 800 Feet. 185 90 80 130 103 150 73 185 85 100 No rock struck; mainly till. Mainly blue till. No roek * enters hard till at .56 feet See 29 T 28 R 8 E Sec. 36, T. 28 E. 8 E Sec. 16, T. 28, R. 7 E Several wells in sand below till Sec. 2, T. 27, R. 8 E No rock struck Sec.4, T. 27, E. 8 E Till, 30 feet ; gravel and sand, 40 feet ; remainder rock, 80 feet. Water from sand below till. Sec. 7, T. 27, E. 7 E Sec. 34, T. 27, R. 7 E No rock; mainly blue till. Schoolhouse well in sand below till Sec. 17, T. 27, R. 7 E - . . . Sees. 16, 17, 20, 21, T. 26, R. 8 E . Several wells 70 to 100 feet froiu sand below till. MARSHALL COUNTY. GENERAL STATEMENT. Marshall County is situated on tlie borders of the Illinois River south of Bureau and Putnam counties. It has an area of 400 square miles, and Lacon is the county seat. About two-thirds of the county is situated east of the Illinois River and is mainly a plain standing about 300 feet above the river. Sandy Creek and Crow Creek lead westward entirely across this portion of the county, the former draining the north and the latter the south border. The portion west of the Illinois rises on the western border to an elevation fully 400 feet above the Illinois River, or about 850 feet above tide, there being a prominent morainic belt (the outer moraine of the Wisconsin series) traversing the western edge of the county from north to south. The broad valley of the Illinois River, averaging about 5 miles in width, is filled to a depth of about 150 feet with gravel and sand. The well at Henry, on one of the terraces (not the highest), reached rock at 135 feet, and wells above this Anllage in Putnam County strike rock at correspond- ingly low level Tlie western jiortion of the county lias a thin sheet of drift on the borders of the Illinois Valley, but there is a heavy deposit along the moraine. The eastern portion of the county is apparently heavily cov- crcil tliroiighout, there being only occasional slight exposures of rock in the WELLS OF MARSHALL COUNTY, ILLINOIS. 6B9 east bluff of the Illinois River or along' its tributaries. At Wenona, on the eastern border of the county, the drift is about 100 feet in thickness and is of similar depth at Toluca. These are the only points at which the distance to rock in that part of the county has been ascertained. But few records of wells were obtained in this county, only a hasty reconnaissance having been made. Nothing was learned to indicate that wells are difficult to obtain. INDIVIDUAL WELLS. At Henry wells are usually obtained at a depth of 60 or 70 feet in tl'e sand of the Illinois River bottom. But a few reach a depth of 100 or 110 feet. An artesian well 1,300 feet in depth obtains a "white sulphur" water in its lower part, pi'obably either from the Lockpoi't (Niagara) or Galena limestone. The drift at this well is 135 feet in depth. The discharge of the well is estimated at 32 gallons per minute from a pipe 3^ inches in diameter At Lacon wells are usually obtained in the sand of the Illinois River Valley at a depth of about 60 feet, though on a higher terrace in the east part of the village a depth of about 100 feet is reached. It is reported that some of the wells in the lower part of the city strike a limestone at about 60 feet, but no very authentic data could be obtained. The Manual of American Waterworks reports that the public water supply is from a well, depth not given. The public water supply at Wenona is obtained from a well 1,854 feet in depth which is reported by residents to have entered the Potsdam near the bottom, but perhaps terminated in St. Peter sandstone. It has a head 120 feet below the surface, or 565 feet above tide. The capacity is estimated at 100 gallons per minute. Strong wells are obtained from the diift in the vicinity of Wenona at depths of 40 to 60 feet. The drift in that vicinity, as already noted, is about 100 feet in depth. At Toluca the coal shafts encounter a large amount of water in the lower part of the drift and also in the sandstones of the Coal Measures. It is proposed to utilize the water from one of these horizons as the public supply, but at last reports (in 1897) the waterworks had not been constructed. 670 THE ILLINOIS GLACIAL LOBE. WOODFORD COUNTY. GENERAL STATEMENT. Woodford County is situated on the east side of the Illinois River, immediately south of Marshall and Lasalle counties, and has an area of 540 square miles, with Metamora as the county seat. The northwestern portion is directly tributary to the Illinois River, through small streams. The remainder of the county is tribiitary to the Mackinaw River, which crosses its southeast border. This is one of the most elevated counties of central Illinois, the uplands being in places about 850 feet and generally 750 feet or more above tide. The Illinois River, on the west border of the county, is only about 430 feet above tide, thus making a valley fully 400 feet in depth. The small streams, therefore, leading down to the valley make very rapid descent. The southwestern border of the county is crossed by the Bloomington morainic system, which has a subdued expression and rises so gradually from the plain on the east that it would scarcely attract notice, though it stands about 50 feet higher than the plain. There is a heavy deposit of drift covering the entire county, if we may judge from the outcrops and the few wells which have reached rock, the thickness at Metamora being 280 feet, at Eureka 150, and at Minonk about 125 feet. Outcrops of rock are reported in a few places in the south part of the county on tributaries of Mackinaw River, and a single outcrop occurs on Panther Creek in the noi'thwest part. So far as known to the wi'iter there are no outcrops in the Illinois River bluffs. INDIVIDUAL WELLS. The public water suppl}^ for Minonk is obtained from a well 1,755 feet in depth, which has a head about 150 feet below the surface, or 600 feet above tide. Water veins are encountered in the Eocarboniferous lime- stone at about 750 feet, but a supply with greater head and volume was obtained in the lower part of the well, at about 1,700 feet, perhaps, from the St. Peter sandstone, no careful record being available. The water is moderately hard and the well has an estimated capacity of 100 gallons per minute. An abundance of water is obtained from the drift in this Aacinity frum a depth of 65 feet downward, rock usually being struck at about 125 WELLS OF WOODFORD COUNTY, ILLINOIS. 67 1 feet. A record of the M. T. Ames coal shaft at Minonk shows yellow and blue tills to a depth of 62 feet, beneath which a harder till is entered, which is interbedded with sand. At Elpaso the strongest wells are obtained, at about 115 feet, from sand beds in the drift. The public water supply is obtained from such wells. The strongest wells in Eureka are found in beds of sand and gravel at a depth of 60 to 100 feet. The waterworks are supplied from wells of this class 60 feet in depth. Private wells are often obtained at depths of but 15 feet. The following detailed record of a prospect boring for coal at this town will serve to indicate the complexity of the drift beds. It is a copy of a sworn statement made to the coal company by Gr. W. Darling, who did the drilling: Section of prospect boring for coal at Eureka^ Illinois. 1. Top soil had been removed. Feet. 2. Hardpan 8 3. Blue clay and gravel 4 4. Bowlders and large stones 2 5. Coarse loose gravel and water 5 6. Dark clay 2 7. Variegated clay, different colors, witli gravel 8 8. Bowlders bedded in clay 6 9. Cement gravel 41 10. Very soft sand rock 3 11. Quicksand, some water 2 12. Coarse gravel i 13. Clay and gravel 24 14. Drift formation, gravel and sand 1 15. Wood drift 1 16. Different colored clay with some stone 43 17. Soft soapstone 12 18. Hard blue soapstone 37 19. Black shale 3j. 20. Coarse coal and sulphur Oj. 21. Good coal (splendid coal ) _ 2 22. Coal debris (or horseback) Ij. 23. Soapstone 9 24. Limestone _ 14 25. Soapstone 34. 26. Limestone 2* 27. Soapstone 7 28. Conglomerate rock, composed of sulphur, lime, iiint, and iron 3 29. Soapstone 47 30. Blue hard slate 9| 31. Black slate, rather soft Xi 32. Hard coal 3. 1 33. Fire clay O^V 34. Soapstone OJ 672 THE ILLINOIS GLACIAL LOBE. At Metamora stroug wells are obtained at about 75 feet. A few wells in the vicinity of this town have been sunk to greater depths and some of them pass throvigh a black muck containing wood under the blue till at a depth of about 140 feet. This muck and associated sand is in some cases 15 feet in thickness. A thin bed of blue clay underlies it, beneath which is a hard gray till, which in a single boring, reaching the rock, was 115 feet in depth. STARK COUNTY. aENBRAL STATEMENT. Stark County is situated west (if Marshall and has an area of 290 square miles, with Toulon as the count)'- seat. It is drained by the two headwater forks of Spoon River, which lead southward tlxrough it and unite just below the county line. The original drift surface was probably nearly plane, but has been much eroded by the streams, for this county lies outside the limits of the Wisconsin and probably of the lowan sheet of drift, and in consequence has been subjected to erosion for a longer period than counties to the east. The surface of the county is capped with loess to a depth of about 15 feet, beneath which is a deposit of glacial drift seldom more than 50 feet deep and in many places but 10 or 15 feet. Wells are ordinarily obtained in the di-ift, but a few obtain water in the rock at moderate depths. INDIVIDUAL "WELLS. At Toulon and in that vicinity rock is entered at about 30 feet and water is usually obtained near the base of the drift. In the vicinity of Wyoming many of the wells encounter a bed of muck or peat at a depth of 20 to 24 feet. This is said to be overlaid by a blue cla}', Ijut opportunity has not been afforded for determining whether it is a glacial deposit or a part of the loess. The wells are usually obtained in sand beneath this peat. In the vicinity of Stark, on a low plain in the south ]iart of the count v, about 40 feet below the general level of the upland, wells reach a depth of 40 feet or more without enterinsr rock. WELLS OF PEORIA COUNTY, ILLi:srOIS. 673 PEORIA COUNTY. GENERAL STATEMENT. Peoria County is situated on the west side of the Illinois River, imme- diately south of Stark and western Marshall, and opposite Woodford and Tazewell counties. It has an area of 615 square miles, and Peoi'ia is the county seat. The principal stream crossing the county is Kickapoo Creek, which lias two forks, one of which drains the northern and the other the western portion of the county. The stream enters the Illinois just below the city of Peoria. The other direct tributaries of the Illinois are very small. Spoon River crosses the extreme northwest corner of the county in a westward course and flows through Knox and Fulton counties before joining the Illinois River. The northeastern part of the county is occupied by two bulky morainic systems, the Shelbyville and Bloomington. West from these moraines the uplands are generally plane and stand about 100 feet lower than the main crests of the morainic systems. Like the neighboring portion of Stark County, this plane is covered with loess to a depth of 12 to 15 feet. The morainic ridges to the east are in places nearly destitute of loess, so that surface bowlders are a conspicuous feature. There are other portions of the moraines, however, which carry a deposit of loess-like silt 5 or 6 feet in depth. The sheet of loess which covers the plain west of the moraines passes under them, as indicated on a previous page (p. 187). The thick- ness of the drift in Peoria County is similar to that of Stark, except that the Illinois Valley and the moraine in the northeastern part of the county each have a very heavy drift deposit, 150 to 200 feet or more in thickness. The drift usually contains a sufficient amount of sand and gravel at moderate depths to afford water for Avells, and in places the entire drift section appears to be composed of sand and gravel. The majority of exposures along Kickapoo Creek are largely of this material, there being but a small amount of till exposed. In the morainic ridges in the northeast part of the county much till is tisually found in wells. Excellent exposures of the till are to be seen along the Santa Fe Railroad in its descent to the Illinois Valley between Edelstein and Chillicothe. JION xxxviii 43 674 THE ILLINOIS GLACIAL LOBE. INDIVIDXTAL WELLS. In the vicinitv of Princeville, in the northern part of the county, wells obtain water in limestone at depths of 20 to 50 feet, but at Monica, only 4 miles west, 100 feet of drift is penetrated, and at Dunlap, 6 miles southeast, wells occasionally pass through 200 feet of drift. The drift appears to have built up an eroded country to a level about even Avith the tops of the rock ridges. Occasionally a rock ridge rises slig'htly above the general level, an instance being found in sees. 4 and 5, T. 11, R. 7 E., about 4 miles northeast of Princeville, where the rock appears at the top of a ridge standing 40 feet higher than Princeville Station. Records of several deep wells made near Dunlap and Alta have been obtained from the driller, Mr. Alexander Lutcavish. In the Aallage of Dun- lap several wells obtain a strong supply of water at 110 to 112 feet Avithout entering the rock. Nearly all the wells find a weak vein at 65 to 70 feet, which is apparently at the base of the Wisconsin till sheet. Occasionally strong wells are obtained at this depth. A well at Harrison Harlan's, 2 miles south of Dunlap, and at an altitude about 50 feet lower than the vil- lage, obtains water from sand and gravel at a depth of 117 feet. It is mainly tlu'ough a stony blue clay. At William Rodgers's, 1^ miles west of Dunlap, on the crest of the Shelbyville moraine, at an altitude about 50 feet above the village, a well reaches a depth of 150 feet without entering rock. Another well at Mr. Powers's, also on the ci-est of the moraine, about a mile south from Mr. Rodgers's, is of similar depth, and also fails to reach rock. A well on "Jubilee Mound," about 5 miles west of Dunlap, 45 feet in depth, passes through 30 feet of yellow till and then enters a very hard blue till containing large bowlders. Blasting was necessary to remove this blue till. This mound is outside the limits of the Wisconsin drift. Mr. Lutcavisli made a boring for John Holmes, sr., one mile east of Alta, which' reached a depth of 370 feet, and apparently did not strike rock. Its lower portion was in a sand too fine to be screened b}' a pump strainer. A bed of muck with wood and leaves was passed through at a depth of 245 to 247 feet. This well is near the crest of the main ridge of the Bloomington moi'ainic system, at an altitude nearly 400 feet aboA'^e the Illinois RiA^er. At the farm of John Holmes, jr., one-half mile Avest of Alta, a Avell Avas obtained at a depth of 125 feet, Avhich has 80 feet of Avater. Mr. William WELLS OF PEOEIA COUNTY, ILLINOIS. 675 Dickison has a well on the crest of the Shelby ville moraine, 2 J miles west of Alta, which was dug to a depth of 156 feet. It entered blue till at less than 10 feet and continued in it to a depth of 117 feet, when a thin bed of very bowldery clay was encountered, which apparently marks the base of the Wisconsin drift. Beneath this clay is a deposit of loess several feet in depth which connects with the surface loess of the districts to the west out- side the limits of the Wisconsin drift. Beneath the loess is a hard till (lllinoian) alternating with beds of sand. Water is obtained in gravel near the bottom of the well and rises only to 20 feet. Mr. John Miller made a well 4 miles north of Dunlap which obtained water from sand and gravel at a depth of 218 feet. The upper 68 feet is evidently Wisconsin di-ift, while the remainder is lllinoian. The drift is almost entirely till. A well was made for Mr. Patrick Hogan about 4 miles south of Alta which reached a depth of 330 feet. Wliether it entered rock was not ascertained. The well is on the crest of the Shelby ville moraine, at an altitude about 375 feet above the Illinois River. In Elmwood and vicinity, in the west part of the county, wells are usually obtained at 25 to 40 feet. The drift in that vicinity is about 60 feet in depth. The Manual of American Waterworks reports that the public water supply is from an artesian Avell, depth not given. At Peoria the public water supply is obtained from a large well 32 feet in diameter and 50 feet in depth, sunk in the low bottom of the Illinois River just above the city. The well passes through a bed of blue till and obtains water from gravel near the bottom. The city engineer, Mr. J. A. Harman, reports that the well will supply 8,000,000 gallons per day, even in dry seasons. It is thought that the bed of blue till overlying the water- bearing gravel protects the water from contamination by access of Illinois River water, or at least there is a probability that any water entering this gravel from the Illinois River passes tln*ough a sufficient amount of sand and gravel before reaching the well to insure the absorption of much of the impurities. Mr. Harman states that this water is preferable to water obtained from the underlying rock strata, for the latter water in this vicinity is brack- ish. Several deep wells have been sunk in the city at the distilleries, stock yards, and by private parties. One of these wells, controlled by D. L. Big- ham, is used to supply the bath house on Adams street, between Hamilton and Fayette. This well penetrated 151 feet of glacial drift, and similar 676 THE ILLINOIS GLACIAL LOBE. depths have been found in other wells in the valley at this city. They show the rock floor to be at an altitude of 350 feet, or 80 feet below the Illinois River. Possibly a deeper portion of the old valley is to be found farther east, as these wells are all situated near the west bluff. Between Peoria and Chillicothe, on a sandy terrace of the Illinois River, standing about 100 feet above the present stream, several wells have been sunk to de^Dths of 90 to 120 feet. They apparently obtain water at about the level of the Illinois River. A few wells on this terrace near the west bluff obtain water at 50 to 75 feet. The Manual of American Waterworks reports that the public water supply at Chillicothe is from driven wells, depth not given. KNOX COUNTY. GENERAL STATEMENT. Knox County is situated in western Illinois immediately west of Stark and Peoria counties. It has an area of 720 square miles, and Galesburg is the county seat. The southeastern portion of the county is crossed by Spoon River in a southwestward course, and about tliree-fourths of the county is tributary to that stream. The northwest one-fourth of the county drains directly westward to the Mississippi River through Pope Creek and two branches of Henderson River. The county has a good surface drain- age, the drainage systems being well matured and the slopes between streams sufficiently rapid to insure the discharge of water not absorbed by the soil. The loess, which forms a capping about 15 feet in thickness, is sufficiently porous to readily absorb a large part of the rainfall and retm-n it to the crops in seasons of drought. The glacial drift is generally but 20 or 30 feet in depth, but in places where valleys have been filled the depth may reach 100 feet or more. The average of 10 borings which enter rock is found to be 35 feet, and this is thought to fairly represent the upland average for the county. The majority of wells are obtained in the drift, some being sunk only to the base of the loess. The strong wells, however, usually penetrate the glacial drift a short distance. INDIVIDUAL WELLS. At Galesburg the public water supply is obtained in part from Avells in the drift and in pni't from deep wells sunk to the St. Peter sandstone. The WELLS OF KNOX COUJfTT, ILLINOIS. 677 wells ill the drift are located along a valley leading westward from the town, and are sunk to depths of 70 or 80' feet without entering rock. They are mainly through sand, and the water rises nearly to the surface. A well was sunk in 1896 to a depth of 1,226 feet, entering St. Peter sandstone at 1,060 feet. The well is cased to the St. Peter and the entire depth j)enetrated in this formation is thought to be a water-yielding rock. The water has a temperature of 60° F. The head is 102 feet below the surface and 635 feet above tide, as determined by careful measurements conducted b}' the city engineer. The capacity is estimated at 120 gallons per minute. As this is but one-eighth the amount needed by the city, the drift wells furnish the greater part of the supply. It is planned to sink other deep wells in order to dispense with the water from the drift, since that is not entirely above suspicion of surface contamination. Many private wells in this city are obtained from sand below loess and till at depths of 25 to 45 feet. The drift is said to be 80 or 90 feet in depth for a distance of 5 or 6 miles north- east from Gralesburg, but within a short distance in other directions rock is found at much shallower depths. At Knoxville the public water supply is obtained from a well 1,350 feet in depth, which was sunk in 1896. It enters St. Peter sandstone at 1,180 feet and continues in that formation to the bottom. The well is cased to the top of the St. Peter sandstone in order to shut out sulphurous Avater struck at higher levels. It has an estimated capacity of 80 gallons per minute. The water has a temperature of 68° F. Private wells are obtained in the vicinity of Knoxville at depths of 20 to 40 feet, either near the base of the drift or in the underlying Coal Measures. At the villages of Wataga, Oneida, and Altona coal shafts usually enter rock at about 30 feet, but wells are obtained near the base of the drift or only occasionally from the rock. At Williamsfield, in the east part of the county, wells are usually obtained at shallow depths in the glacial drift, seldom exceeding 40 feet. The record of a well about 1 1 miles west of this village is found to show 85 feet of di'ift. without entering rock. The cuttings along the Santa Fe Railway between Williamsfield and Dahinda expose a complex series of sand and till beds in the descent to Spoon River. Wells on the bordering uplands appear to penetrate a similar complex series. At Yates, in the southern portion of the county. Coal Measures shale 678 THE ILLINOIS GLACIAL LOBE. is entered at about 30 feet, but wells are usually obtained without enter- ing the rock. A drift ridge leading east from this town and standing 30 or 35 feet above the general level of the plain is found to have a black soil beneath till at about the level of its base. This soil has been struck in several wells. At Abingdon wells are iisually obtained from rock at depths of only 25 or 30 feet. The di-ift is in places but 1 5 feet in thickness. WARREN COUNTY. GENERAL STATEMENT. "Warren County is situated immediately west of Knox and has an area of 640 square miles, with Monmouth as the county seat. The drainage is mainly westward through Henderson River and other streams into the Mississippi. The southeastern portion of the coimty, however, drains eastward 'to Spoon River. The features of this county are very similar to those of Knox, thei'e being a well-drained surface and comparatively thin covering of drift. The loess is fully as thick as in Knox County and equally pervious to water. At the base of the loess numerous springs are to be seen where it outcrops along the sides of ravines. INDIVIDITAL WELLS. At Momnouth the public water supply is from two wells, each about 1,227 feet in depth. They enter the St. Peter sandstone 156 feet. One was cased to the top of this sandstone, but the other was not cased to so gi-eat a depth, for the reason that a water vein was found at a depth of about 935 feet which seemed desirable to admit to the well. The head in the well cased to the St. Peter sandstone is 60 feet below the surface and 675 feet above tide. No data have been obtained concerning the head in the other well. The capacity of the first-named well is estimated at 200 gallons per minute. An analysis of its water appears in the Seventeenth Annual Report of this Survey.^ Private wells of considerable strength are obtained in the vicinity of Monmouth at a depth of about 60 feet, in some cases from the glacial drift. There are also shallower wells of less strength. I Part II, p. 827. WELLS OF HENDERSON COUNTY, ILLINOTS. 679 111 the southeast part of the county rock is often struck on the high points at 25 feet or less, but on lower ground the drift is usually thicker. In the southwest part of the county the drift appears to have an average depth of at least 50 feet, and wells seldom reach the rock. The Manual of American Waterworks (1897) reports that waterworks systems have recently been introduced at Alexis, Kirkwood, and Roseville. In each village the supply is from a well. That at Kirkwood is reported to be insufficient for the needs of tlie village. HENDERSON COUNTY. GENERAL STATEMENT. Henderson County borders the Mississippi River in the western part of the State, immediately west of Warren and south of Mercer County. It has an area of 380 square miles, and Oquawka is the county seat. The county is drained mainly by Henderson River and its tributaries, which lead westward to the Mississippi. The southern portion is tributary to Honey Creek, which leads westward entirely across the county. There is a strip of the Mississippi bottoms along the west border of the county having an average width of about 5 miles, much of which is subject to overflow and is sparsely settled. The remainder of the bottom land is very sandy. The uplands, which stand about 200 feet above the river, are covered with loess to a depth of 20 feet or more. In places the loess has been heaped into dunes and ridges on the brow of the bluffs, which stand 50 feet or more above the uplands to the east. In places also sand in dunes appears along the brow of the bluff. But few records of wells have been obtained in this county, and these indicate considerable difference in the distance to rock, there being a range from 20 feet to over 160 feet. The rock floor of the Mississippi Valley probably stands nearly 160 feet below the level of the bottoms, its elevation at Fort Madison, Iowa, just beyond the limits of this county, being 360 to 370 feet above tide, or about 140 feet below the level of low water at that city. Preglacial tributaries of this valley would be excavated to a corre- spondingly low level; hence we may expect to find a drift filling of not less than 300 feet on the portions of the uplands adjacent to the Mississippi, where the valleys have been filled to the level of the upland plain. 680 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL AVKLLS. At Oquawka wells are obtained by driving pipes to a depth of 4C) to . GO feet in the sand of the Mississippi bottoms, and wells of this class are common tlu'oughont the settled portions of these bottoms. In the vicinity of Biggsville rock is entered on the uplands at a depth of about 40 feet, but wells are usually obtained at 12 to 30 feet. Similar conditions prevail in the vicinity of Media and Stronghurst, though the drift occasionally exceeds 50 feet. Near Decorra, in the southwest part of the count}', several wells have been sunk to depths of 90 to 150 feet. They usually enterrock within 100 feet of the surface. About 2 miles southeast of Decorra rock is struck in several wells at only 30 feet. At Stronghurst a deep well was drilled by the Stronghurst-Media Company in the winter of 1897-98 with a view to obtain oil. Instead water was obtained, which rises to within 30 feet of the surface, or 643 feet above tide. The log of the well kept by the drillers, Wilson Brothers, of Belleville, Illinois, is as follows (names in parentheses are by the writer): Section of an oil boring at Stronghurst, Illinois. Feet. 1. Glacial drift, largely blue clay 150 2. Gray shale (Kinderhook?) 165 3. Limestoue (Devonian and Upiier Siluriaa?) 105 4. Shale (Hudson River Group?) 165 5. Gray limestone (Trenton?) 200 6. Brown limestone (Trenton?) lo 7. Gray limestone (Trenton?) 60 8. Sandstone (St. Peter?) 71 9. While shale 25 10. White limestone 10 11. White shale 5 12. White limestone 24 13. White saudatoiio 20 14. Limestone 50 15. Shale 5 16. Limestone 105 17. Sandstone 5 18. Limestone 25 19. .St. Croix (?) sandstone 290 20. Sandstone 6 Total , 1.601 There was a strong yield of water in the Trenton and in the sandstone strata at lower dejjths. WELLS OF HAifOOCK COUNTY, ILLINOIS. 681 HANCOCK COUNTY. GENERAL STATEMENT. Hancock Coiint}^ borders on the Mississippi below Henderson County and opposite the extreme southeast corner of Iowa. It has an area of 769 square miles, and Carthage is the county seat. Although bordering the Mississippi RiA^er, a considerable portion of the county is tributary to the Illinois River. In the north part of the county the divide between the Illinois and Mississippi rivers is only 3 or 4 miles from the east bluff of the Mississippi. The principal stream leading to the Illinois in this county is Crooked Creek, which drains the northeastern fourth of the county. The principal stream tributary to the Mississippi is Bear Creek, which drains the southwestern fourth of the county southward into Adams County and thence westward into the Mississippi. Along much of the northern half of the border of this county the Mississippi River is in a new course and occupies the entire width of its valley. The distance between bluffs is but little more than a mile. In the remainder of the border the river is in a pregla- cial course, with bottoms 6 or 8 miles in width. These bottoms are mainl}- on the Missouri side, though near the south line they extend 3 or 4 miles into this county. The uplands stand 150 to 200 feet above the river and are generally plane. There is, however, a well-defined drift ridge leading southward from Warsaw a short distance east from the river bluff, a ridge which, as previously described, apparently marks the western limit of the Illinois glacial lobe. The thickness of the drift varies greatlj^, owing to the presence of deep preglacial valleys which haA^e been filled to a level as great as the border- ing: uplands. In such valleys rock is not usuallv entered at less than 200 feet, but on the bordering uplands it may be entered at 20 feet. There is usually, however, 50 or 60 feet of drift on the preglacial uplands. One of the most conspicuous of these buried valleys revealed by the wells is found in the central portion of the count}-, near Carthage, and a portion of its course is along the present water parting between the Illinois and the Mis- sissippi rivers. This valley a^jparently leads southward into Adams County along' a line a short distance east of the A^alley of Bear Creek. Perhaps its lower course is followed by Bear Creek. The drift is mainly a compact till, and in places wells are difficult to obtain. A large number of wells have been sunk to a depth of 100 to 200 682 THE ILLINOIS GLACIAL LOBE, feet, or even more, many of them entering limestone before obtaining a strong vein of water. A portion of the lUinois-Mississippi divide is fiat and poorly drained, bnt the portions of the county adjacent to the Mississippi, and also to Bear Creek and to Crooked Creek, are greatl)^ eroded. INDIVIDUAL WrELLS. At Dallas, on the northern border of the county, in the Mississippi Valley, wells are usually obtained at 20 to 35 feet, mainly in limestone. Occasionally they are sunk to a depth of 150 feet. At Nauvoo, on the brow of the Mississippi blutf, in the northwest part of the county, the wells are usually obtained at about 20 feet, in sand. Rock is entered at 25 to 30 feet, but wells seldom reach it. At Laliarpe, on the upland plain, in the northeast part of the county, the strong wells are obtained in sand below till at a depth of about 60 feet. One well made by Mr. Bainter enters rock at 100 feet. In the vicinity of Webster and Fountain Green, in the east part of the county, wells 50 feet in depth do not reach rock. They are mainly through till. Between these villages and Laharpe there is an area of several square miles in which the rock is so near the surface that sink holes abound. At Carthage the public water supply is obtained from two deep wells, one of which terminated in the St. Peter sandstone at 1,000 feet, but the other continued to a depth of 1,700 feet. AVater veins are struck in the Niagara limestone at about 750 feet; in the Galena limestone at 865 feet, and in the St. Peter sandstone at 975 feet. The head is about 16 feet below the surface, or 660 feet above tide. The water is rather unpleasant on account of salinity. The following record of strata penetrated by one well before reaching the St. Peter is taken from the Geology of Illinois:' Section of deep tcell at Carthage, Illinois. Feet. Drift, clay, sand, and gravel 214 White limestone 70 Shale 355 Limestone 336 St. Peter sandstone, penetrated 25 Total depth 1. 000 At Elvaston wells are obtained at 12 to 16 feet, and also at 20 to 30 feet, from beds of gravel associated with till. 'Vol. VIII, p. 65. WELLS OF HANCOCK COUNTY, ILLINOIS. 683 At Hamilton, on the brow of the Mississippi bluffs, in the west part of the county, the best wells are obtained in the rock, which is entered at 20 or 30 feet. Many weak wells, however, are obtained from the drift. An artesian well has been sunk at Ringland's Sanitarium, in the north part of the village. It has a depth of 680 feet and obtains a flow from the Lockport (Magara) limestone, which is penetrated about 25 feet. The head is reported to be 63 feet above the surface, or aboxit 660 feet above tide. At Warsaw several artesian wells have been sunk, one by the village and others by corporations and private individuals. The village well is mainly for fire protection. Gen. Oliver Edwards, of Warsaw, has furnished the Survey a carefully prepared body of statistics concerning the wells, and these statistics are presented in the discussion of artesian wells in Illinois appearing in the Seventeenth Annual Report of this Survey. The wells all terminate in the Galena or Trenton limestone and have depths ranging from 750 to 860 feet. The original head at each of the wells was about 680 feet above tide, but at present it scarcely exceeds 600 feet. The water is sulphurous, but otherwise not of unpleasant quality. At Plymouth, in the eastern part of the county, it is proposed to obtain a public water supply from an artesian well.^ At Augusta, in the southeast corner of the county, wells are usually obtained in sand contained in the di'ift, at depths ranging from 20 to 60 feet. A few have been drilled into the underlying Coal Measures to depths ranging from 120 to 265 feet. The following table embraces the deepest wells, not reported in the above discussion, of which records were collected. They are confined mainly to the southern half of the county : . Wells in Hancock Cotmty. Owner or location. Altitude (above tide). Depth. Kemarlis. Sec. 11, T. 4, R. 9 W Feet. 645 620 625 660 Feet. 73 50 80 45 Sec 12 T. 4 K 9W rock. Enters rock at 45 feet. Sec. 12, T. 4, R. 9 W No rock ; mainly sandy drift. Rock entered at 40 feet. Sec. 7. T. 4. R. 8 AV 'Manual of American Waterworks, 1897. 684 THE ILLINOIS GLACIAL LOBE. Wells in Rancoclc County — Coiitinued. Owner or location. Altitude -n^^ti, (above tide). ^^P''''- Remarks. W. McCuen, 4 miles south of Hamilton. Sec. 30, T. 4, K. 8 W Sec. 31, T. 4, R. 8 W Sec.31, T.4,R.8W Sntter and Vicinity Tioga aud vicinity J, D. Wood, at Chili Mr. Cunningham, 2 miles northeast of Chili. Mr. Dickersou, 2 miles north of Chili. Bowen and vicinity Owens's mill at Still well Sec. 1, T.3, R.7W Sec. 36, T. 4, R. 7 W East part T. 4, R. 6 W Sec. 4, T. 4, R. 6 W Sees. 15 aud 16, T. 4, R. 6 W . . . . Sec. 20, T. 4, R. 6 W Sec.29,T.4, R. 6W Sec. 28, T. 4, R. 6 W Gittings Mound, north line of county- Feel. 690 750 710 750 690 700 670 670 Feet. 690 670 670 74 60 63 42 40 40 70 80 220 70 217 198 660 192 660 40 670 75 680 100 690 195 700 1,030 700 100 750 41 Loess, 12 feet; grayish-yellow gummy clay, 22 feet; blue till, 8 feet; peaty soil with wood, 5 feet; blue till, 28 feet. No rock; mainly gray till. Rock entered at bottom. Surface silt, 10 feet; brown clay, few pebbles, 15 feet; yellowish-gray till, 17 feet. Rock entered at about 25 feet. Surface silt, 8 to 10 feet; yellow till, 20 to 25 feet; sand, 5 feet. Yellow and brown clays, 15 feet; gray gummy clay, 10 feet; yellowish-gray till, 40 feet; bard blue till, 20 feet ; rock at bottom. Two wells enter rock at 75 or 80 feet. Surfcice silt, 6 feet; grayish gummy clay and yellow till, 34 feet; blue clay with few pebbles. 160 feet; gray sand, 10 feet; cemented gravel, 5 feet; loose gravel, 5 feet. Several wells enter rock at 65 or 70 feet ; drift mainly till. Rock entered at 207 feet. Yellowish clays, 20 feet; blue clay, 175 feet; sand, 3 feet. Yellow clay, 20 feet; blue clay, 168 feet; sand with wood, 4 feet. Rook entered at 30 or 40 feet. Rock at about 75 feet. Rock struck at about 100 feet. Silt and yellow clay, 26 feet; blue clay, few peb- bles, 169 feet; sand at bottom, 6 feet. The well enters rock at 200 feet aud terminates in St. Peter sandstone; water rises to 40 feet below surface. Rock at about 100 feet. Yellow till, 30 feet; blue till, 11 feet; sand at bot- tom. WELLS OF Mcdonough county, Illinois. 685 Mcdonough county, general statement. McDonougli County is situated east of Hancock and has an area of 540 miles, with Macomb as the county seat. The county is drained ahnost entirely by Crooked Creek, through several tributaries leadiug southwest- ward to that stream. The surface is generally much eroded, but there is a flat strip on the north and east borders in which drainage is rather imperfect. The county is covered to a depth of 8 to 12 feet or more with a j^orous sheet of loess which absorbs water rapidly and returns it to the crops in seasons of drought. The drift is composed largely of a compact till, and in places strong wells can not be obtained in it. Throughout much of the county, however, the wells do not enter the rock. There is apparently a general coating of 50 to 75 feet of drift, and in places a much greater depth. In the extreme northeast corner, however, near Prairie City, the rock rises in ridges slightly above the general level of the upland plain. INDIVIDUAL WELLS. At Prairie City wells on the rock ridges are sunk to depths of 50 feet or more ; those on the plane tracts obtain water in the drift at 20 to 30 feet. At Bushnell the public water supply is obtained from a well 115 feet in depth which does not enter rock. A well at the Toledo, Peoria and Western Railway station enters rock at 140 feet. The drift consists of about 20 feet of loess and yellow till, beneath which is a heavy sheet of blue till. Wells are obtained from thin beds of sand and gravel in the blue till, or occasionally at the top of the till. At Macomb the public water supply is obtained from a well 1,630 feet in depth. The well is cased to the St. Peter sandstone, which is entered at 1,135 feet, and the entire supply is from that sandstone. An analysis made by this Survey is published in the Seventeenth Annual Report (Part II, pp. 925, 926). The water is moderately hard, but its chief mineral ingre- dients are sodium chloride and sodium sulphate. Some dissatisfaction with the use of the water is felt because of these ingredients, though the quality is similar to that of the water from several other wells in use in western Illinois. The drift at Macomb has a known range of nearly 100 feet in 686 THE ILLINOIS GLACIAL LOBE. depth. The deep well penetrates 145 feet, hut in })arts of the city at similar altitude rock is entered at only 60 feet. At Adair the wells are usually 25 or 30 feet in depth, though they occasionally pass into the rock, which is entered at about 60 feet. The di-ift is mainly bkie till, which is entered at only 10 or 12 feet from the surface. At Good Hope the village well is 33 feet in depth and has the follow- ing section, reported by R^^ S. D. Peet : Section of town well at Good Hope, Illinois. Feet. Loess 16 Pebbly brown clay 2 or 3 Saud with a few pebbles - 9 Fine sand with ferruginous crust 2 Blue sand 2 Blue till 2 Wells in tlie vicinity of Good Hope enter rock at depths ranging from 45 to 8 b' feet, and are mainly through blue till. FULTON COUNTY. GENERAL STATEMENT. Fulton County is situated east of McDonough and has the Illinois River on its eastern border. The area is 870 square miles, and Lewistown is its county seat. The principal stream traversing the county is Spoon River, which passes in a southward course through its western part. The surface, like that of the adjoining counties on the north and west, is well di-ained. In addition to the drainage lines, which carrj- oif much of the sur- plus rainfall, there is a capping of porous loess which absorbs a lai-ge part of the rain and returns the water to the soil in seasons of drought. The drift is in thickness similar to that in adjoining counties. An average of sections on the uplands reaching rock is 41 feet. In preglacial valleys the thickness is much greater, for the main valleys were cut to a level 75 feet or more below the low water of the present Illinois. The majority of wells are obtained without entering the rock, there being a sufficient amount of sand and gravel interbedded with the till to ailbrd a strong supply of water for wells. INDIVIDUAL AVELLS. At Farmington, in the northeast corner of the county, the drift is only about 20 feet in thickness and wells are frequently sunk to slight depth in WELLS OF FULTOK COUNTY, ILLINOIS. 687 the underlying rock. Similar conditions prevail at the neig-hboring village of Fairview, and also at Avon, in the northwest part of the county. Fire protection is obtained at Avon and Farmington by pumping from wells to tanks. The city of Canton obtains its public water supply from two deep wells, one of which reaches a dej^th of 2,500 feet and the other 1,646 feet. The latter terminates in the St. Peter sandstone, but the former may reach the Potsdam sandstone. Water is found in the Gralena limestone at 1,100 to 1,300 feet, as well as in the St. Peter sandstone and lower strata. The deeper well, with a diameter of but 4 inches, has an estimated capacity of 125 gallons a minute. The shallower one, with a diameter of 6 inches, will yield 260 gallons a minute. The former well is cased only 90 feet and has a head 630 feet above tide, or about 30 feet below the surface. The latter well is cased 797 feet and has a head 615 feet above tide, which is 15 feet above the surface, this well being located on ground about 60 feet lower than the other. The following record of the strata penetrated by the shal- lower well was published in a Canton paper at the time of the completion of the well: Section of a deep ivell at Canton, Illinois. Feet. Surface 14 Blue shale 29 Gray shale 45 Blue shale 40 Coal 1 Fire clay 6 Blue shale 35 Gray shale 22 Coal 2 Slate 12 Shale 55 Limestone, sandstone, and shale 65 Shale 15 Black limestone 7 Limestone, flint, sandstone, shale, white marl 192 Shale 225 Limestone 63 Limestone and shale (mixed ) 272 Trenton limestone (water bearing, flow) 265 Limestone, sandstone, shale, etc 100 St. Peter sandstone (water bearing, flow) 241 J In the above section the first 247 feet of rock should perhaps be referred to the Coal Measures ; the next 279 feet are probably Eocarbon- iferous limestone, shale, etc. ; the following heavy bed of shale (225 feet) is 688 THE ILLINOIS GLACIAL LOBE. jDvesumably Kinderhook; the next 335 feet is probably to be referred to the Niagara and Hudson river formations ; and the next 305 feet to the Galena and Trenton. The public water supply for the city of Lewistown is obtained from a series of wells in Spoon River Valley about 20 feet in depth. The town is situated on an upland, pi'obably 130 feet above the river, and the wells there are obtained from gravel in the glacial drift at a depth of 25 to 35 feet. At Astoria, in the southern part of the coiinty, wells are obtained at 20 to 40 feet from saud below till. The drift in that vicinity ranges from 30 to 70 feet in depth, and is largely till. At Vermont, on the west border of the county, wells are usually obtained at 25 to 35 feet. The drift in the vicinity of that village is about 60 feet in depth. A test boring for coal, oil, etc., was made at this village to the depth of 2,487 feet, which probably reached the Potsdam sandstone, but the boring is not utilized for water. At Ipava a well 1,570 feet in depth supplies the waterworks, and is used also by a woolen mill. A sulpho -saline water was struck, pi-obably in the Galena, at a depth of 1,010 feet. A water of more pleasant taste is obtained from the St. Peter sandstone. Strong wells are obtained in the vicinity of this village, either from drift or from rock, at about 100 feet. MASON COUNTY. GENERAL STATEMENT. Mason County is situated on the east side of the Illinois River opposite Fulton County, and has an area of 560 square miles, with Havana as the county seat. The county occupies a low basin-like expansion of the Illinois Valley, heavily covered with sand, except where old river channels have left a surface deposit of muck. The drainage is imperfect, and extensive arti- ficial ditching has been necessary to render the old river channels produc- tive. Much of the county is so sandy that it is not cultivated. The eastern jiortion, however, is very fertile, the sand there being a fine deposit approxi- mating a loess. The thickness of tlie drift is known only at a single point — Mason — where it is 204 feet. The wells are usually obtained at depths of 20 to 40 feet, but at Havana they are frequently sunk to a depth of 70 feet, through sand and gravel. WELLS OF MASON COUNTY, ILLINOIS. 689 INDIYIDUAL WELLS. At Mason the wells often reach a depth of 130 feet, though some water can be obtahaed at 35 feet. A prospect boring for coal at this town penetrated the following complex series of di-ift deposits : Section of drift beds in a coal boring at Mason, Illinois. Ft. In. Black soil 5 o Yellow cjay 30 Yellow Baud 5 Gray sand 32 7 Blue clay 1 o Fine sand 23 11 Hardpan 15 6 Blue clay _.. 7 Sand 11 Sand and gravel , 20 Coarse sand 10 Sand and gravel 33 Fine red sand _. o 4 Dark sand ._ l 8 Gravel and bowlders _ 5 4 Sand 3 8 Total drift 204 Several beds of coal were passed tlu-ough in the underlying Coal Meas- ures, the thickest being 34 inches, struck at a depth of 290 to 293 feet. The rock floor at this well is 394 feet above tide, the well mouth being 598 feet. The public water supply at the city of Havana is reported by tlie Manual of American Waterworks to be obtained from 10 driven wells, 72 feet in depth and 6 inches in diameter. Near San Jose, in the northeast part of the county, wells on the swampy land are obtained at about 30 feet. They penetrate 6 feet or more of black muck, beneath which they are in a fine blue sand to near the bottom, where gravel is struck. On the higher ground east from San Jose wells are fre- quently sunk to a depth of 100 feet or more, largely through sand and gravel. TAZEWELL COUNTY. GENERAL STATEMENT. Tazewell County is situated northeast of Mason, on the east side of the Illinois River, and has an area of 650 square miles, with Pekin as the county seat. The county is traversed nearly centrally from east to- west by MON xxxviii 44: 690 THE ILLINOIS GLACIAL LOBE. Mackinaw River, wliicli enters the Illinois just below Pekin. The northern part of the county is di'ained by Farm Creek, n'hich enters the Illinois oppo- site Peoria. About one-fourth of the county is situated in the Illinois River valle\-, in the northward continuation of the basin referred to in the descrip- tion of Mason County. The uplands have an extreme altitude of about 450 feet above the Illinois River and a general elevation of nearly 300 feet. The Bloomington morainic system crosses the northeast part of the county and the Shelbysalle or outer moraine of the AVisconsin drift leads north- westward through the central portion. Between these moraines there is a narrow plane tract scarcely 5 miles in average width. The portion outside the Wisconsin drift is mainly within the valley of the Illinois River, but a naiTOw strijD of upland is found between the moraine and river bluff south from Pekin. There are rock outcrops at a few points along the east bluff of the Illi- nois River, but the Avell borings distributed widely over the county indicate that the drift is a heavy deposit. Twenty borings wliich do not reach rock have an average depth of 135 feet, while four which reach rock penetrate an average thickness of 247 feet of di-ift. It is probable that the aA'^erage for the countv is not less than 200 feet. In the Illinois Valley the drift is largely gravel and sand, but on the uplands there is a heavy sheet of soft blue till deposited at the Wisconsin stage of glaciation. The deep wells frequently enter a hard till near the bottom, which is presumablv the deposit of an earlier stage of glaciation, and contemporaneous with the sheet of drift found outside the limits of the Wisconsin drift. Wells are often obtained at depths of but 25 or 30 feet, and the depth rarely exceeds 75 feet. INDlVIDtTAL WKLLS. Tlie public water supph* of AVashingtou is obtained from wells driven in the drift to a depth of 60 feet or more, the supply coming from sand below till. This sand is usually entered at about 30 feet. A well at Andrew's mill, in AVashington, 227 feet in depth, is thought to have entered z'ock 2 feet. There was a change from soft to hard till at about 150 feet. A well at the Milburn stock farm, near AVashington, 23() feet in depth, did not reach rock. It was mainly through till. Some intiaunnable gas was encountei'ed near the bottom. A well at AA'illiam Kiel's, about 4 miles west WELLS OF TAZEWELL COUNTY, ILLINOIS. 691 of Washington, reciched a depth of 262 feet without entering- rock. Several changes in structure were noted during the boring. At Morton the waterworks well is 230 feet in depth and terminates in sand. Three other wells within 2 miles northwest reach abont the same dejjth without entering rock, and have similar sections. The waterworks well is reported to have penetrated 30 feet of yellow clay and sand at sur- face, beneath which was 70 feet of soft blue till, belonging apparently to the Shelby ville drift sheet. The next 100 feet is mainlv a hard graA' till, but includes about 20 feet of sand. The lower 30 feet is white sand. At Pekin the public water supply is obtained from the g-ravel of the Illinois River Valley. A large well, 50 feet, in diameter, is excavated to a depth of 30 feet, in the bottom of which several small wells are driven 50 feet farther. The wells will yield 3,000,000 gallons a day. Distilleries at this citv use the Illinois River water. An artesian well sunk on a high terrace in the east part of the city at the City Park reached a depth of 850 feet, and struck salt water at about 500 feet. The well mouth is 100 feet above the level of the Illinois River, or 525 feet above tide, and a flow of water is obtained. The drift is about 200 feet in thickness. ' Within a half mile east of the well rock is exposed in the bluff at an altitude 25 feet higher than the well mouth. At Delavan the public water supply is from a well obtained in sand and gravel at a depth of 160 feet. A well was sunk by this village to a depth of 241 feet without entering rock, and penetrated the following beds: Section of a boring at Delavan, Illinois. ¥aet. Yellow till 15 Blue till 60 Black muck with wood 6 Greeu mucky clay , 8 Gray sandy till 30 Gray sand 122 Total depth 241 " The muck found beneath the blue till is probably at the base of the Wisconsin drift sheet. A well 4 miles northeast of Delavan at an altitude about 80 feet above the village, or 700 feet above tide, struck rock at a depth of 313 feet. The drift was mainly till to a depth of 140 feet, and included a bed of black muck near the base. The remainder of the sec- tion is principally sand, as at Delavan. (392 THE ILLINOIS GLACIAL LOBE. In the vicinity of Green Valley village, on the portion of the Illinois bottoms northwest from Delavan, several wells have been sunk to a depth of over 100 feet through sand and gravel without entering rock. In one case a depth of 145 feet was reached. At the east border of the valley, however, the wells in some cases penetrate 40 to 60 feet of clay before entering sand and gravel. One in sec. 6, T. 22, R. 4 W. penetrated 60 feet of clay, then 75 feet of fine sand, and obtained water in the gravel at bottom. Another in sec. 7 of the same township penetrated 62 feet of clay and 30 feet of sand, when a water-bearing gravel was struck. At Hopedale the railway well is 195 feet in depth without reaching rock. It was mainly thi'ough till to a depth of 160 feet, beneath which sand was encountered. A bed of black muck was passed tlu'ough between till sheets, but the precise depth was not noted. Between Hopedale and Armington, a well on the farm of Robert Pratt, 250 feet in depth, is thought to have struck rock at the bottom. The well mouth is about 650 feet above tide. At Mackinaw a boring 160 feet in depth was mainly through till to 140 feet, beneath which sand was entered which yields an inflammable gas. Wells at this village usually obtain water in sand and gravel between till sheets at a depth of 35 or 40 feet. The waterworks well is 65 feet deep, and is scarcely adequate to supply the village. In the vicinity of Cooper, on the crest of the inner strong ridge of the Bloomington morainic system, at an altitvide about 820 feet above tide, wells are frequently sunk to a depth of 150 feet, mainly through till. In some wells a black muck is found between tills nearly 150 feet below the surface. McLean county, general statement. McLean County is situated east of Tazewell, with Bloomington as the county seat. It is the largest county in the State, its ai-ea being 1,166 square miles. The northern half of the county is tributary to the Mackinaw River, with the exception of a few square miles in the northeast corner, whicli are drained northward to the Illinois-Vermilion. The southern half is drained by the Sangamon and its tributaries. The valleys are all small, within tlic limits of the county, and in many cases are mere ditches cut to WELLS OF MCLEAN COUNTY, ILLINOIS. 693 a depth of but a few feet. The greater part of the county is, however, sufficiently di-ained to need but Httle artificial ditching-. This is one of the most elevated counties in central Illinois, mu'^h of its surface being- more than 800 feet above tide and occasional points 900 feet. The northern border and also the southwest corner fall below 750 feet. A very small area in the southwest corner falls below 700 feet. The Bloomington inorainic system traverses the county neai-ly centrally in an east-west direction and occupies a Ijelt 6 to 10 miles in width. The Mfickinaw River drains its north border and the Sangamon and tributaries its south border. A small moraine, Cropsey Ridge, follows the north border of the Mackinaw River across the northeast part of the county, separating this drainage system from the Vermilion drainage system. The di-ift is of great depth, averaging probably over 200 feet. Records of ten deep borings were obtained which reach rock at an average of 155 feet, but twenty-one others have an average depth of 174 feet without entering rock. The drift is apparently thinnest in the northern part of the county, where rock is struck at about 100 feet. The drift in the central and southern portions has a depth of 200 to 250 feet. Buried soils are found at two or more horizons at depths usually of 100 feet or more, but on the plain outside the morainic system a soil occurs at 40 feet or less. The drift above the first buried soil is usually a soft blue till. At greater depths the till is frequently found to be very hard, as in the neighborino- counties to the north and northeast, already discussed. In some of the deep borings a large amount of sand and gravel is found in the lower part of the di-ift. Many wells have been sunk to a depth of 150 to 200 feet in order to reach the water-bearing beds beneath the blue till, there being only a small amount of water-bearing gravel interbedded with the blue till. INDIVIDUAL WELLS. At Chenoa, on the north border of the county, several strong wells have been obtained from depths of 100 to 150 feet near the surface of the Coal Measures sandstone. The public supply is from two wells 135 and 214 feet in depth.^ Rock is entered at this village at about 80 feet. Wells from the drift are usually weak compared with those from the rock. ' Manual of American Waterworks, 1897. 694 THE ILLINOIS GLACIAL LOBE. The Waterworks Manual reports that Lexington has its public svipj^ly from a well, but the depth is not given. At Colfax borings for coal entered rock at 100 to 125 feet, but wells are usually obtained at moderate depths, seldom exceeding 40 feet. The drift contains considerable sand in that vicinity. The record of a well about 4 miles west of Colfax shows scarcely any till in a depth of 115 feet, at rt'hich depth rock was entered. The city of Bloomington obtains its water supplv from a large well 60 feet in depth, located in the valley of Sugar Creek. The well penetrates about 33 feet of surface gravel, beneath which is blue clay and water- bearing gravel at 60 to 65 feet. Prospect borings show a belt of gravel about 2,000 feet in width leading down the creek valley from the vicinity of the waterworks. Except in seasons of extreme drought, such as that of 1894 and 1895, the waterworks well can be depended upon to furnish an adequate supply for the city. The coal shaft near the Cliicago and Alton Railway station, at an altitude of about 750 feet, entered rock at a depth of 161 feet, penetrating the following drift beds: Section of drift beds in a coal shaft in Bloomington, Illinois. ■Feet. Loam and gravel 20 Blue till \^9 T, J. • ^JTKj -A^> ^ J-J ••«**• ««rtvBa blue till, 12 feet; sand and gravel, 6 feet; hard. blue till, 40 feet; soft blue till, 56 feet. Sec. 9, T. 24, R. 4 E 775 95 Yellow till, 15 feet ; soft blue till, 65 feet : hard sandy blue till, 15 feet. Sec. 28, T. 24, R. 4 E. 850 198 Maiuly till, 136 feet; sand and gravel with gas, 62 feet; shale at bottom. Sec. 36, T. 24, R. 4 E 850 180 Mainly sand; probably rock at bottom. Sec 6 T 24 R. 4 E 800 230 Yellow till, 18 feet; bine till, 60 feet; white sand, KJ^\J9 Kff J^ • ■■ ''■J -■-Vt T. -*-* -•■• ABB« BBBH 80 feet; blue sand, .">0 feet; gravel, 7 feet; blue clay to bottom, 13 ieet. Sec. 21:1, T. 24, R. 1 W 725 256 Loess and yellow till, 12 feet ; blue clay with few pebbles, 244 feet; gas at 111 feet. Sec. 29, T. 24, R. 1 W 725 192 Loess and yellow till, 12 feet; blue clay, few jieb- bles, 95 feet; hard blue till, 83 feet; no rock. Sec. 34, T. 24, R. 1 W 725 200 Loess and yellow till, 18 feet ; soft blue till, 182 feet ; rook, perhaps a bowlder, at bottom. Sec 2 T.23,R.1W 725 217 Maiuly blue till; gravel at bottom. Blue till entered at 40 feet; black muck with wood Sec. 3, T. 23, R. 1 W 725 246 and leaves at about 200 feet. Mrs. Cowdon, at (iilleiii S20 116 Mainly blue till; gr.avel at bottom. WELLS OF VEEMILIOF COUNTY, ILLINOIS. Wells of McLean County — Continued. 697 Owuer or location. Altitude (above tide). Depth. Kemarks. Feet. Feet. E. McGraw, 1 mile east of Gil- 825 127 Mainly blue till ; gravel at bottom. lem. Southwest part T. 23, E. 4 E . . . 850 187 No rock struck. Sec. 7, T. 22, R. 4 E 800 176 Yellow silt and till, 15 feet; soft blue 1 ill, 24 feet; black muck with wood, 4 feet ; greenish clay, 10 feet; gray clay and sand, 8 feet; blue- gray till, 113 feet. J. Paiuter, 5 miles north of 825 190 No rock struck. Le Roy. H.Vert, 4 miles north of LeEoy 875 221 No rock struck. Leroy, coal boring 778 200 Mainly till, 56 feet; sand, 145 feet; no rock. Gas from drift at about 100 feet. Sec 3 T. 22, R 4 E 850 850 100 100 4 miles northeast of Ellsworth. Gas from drift at about 100 feet. VERMILION COUNTY. GENERAL, STATEMENT. Vermilion County is situated on the east border of the State, about midway of the east line, and has an area of 926 square miles, with Danville as the count V seat. 1 1 is drained naaiiily by Wabash- Vermilion River, whose North Fork leads through the northeastern part of the county, the Middle Fork through the northwestern, and Salt Fork through the western. The south border of the county is drained eastward through Little Vermilion River and the extreme northwest border is drained northward to the Iroquois River. The north-central portion of the county is occupied by the Blooming- ton morainic system, which is here differentiated into two belts, each of which in places presents a double ridge. The south border of the county is traversed by the Champaign morainic system, whose main ridge lies south of Little Vermilion River, but which has a minor ridge leading eastward across the county a few miles farther north than this stream. In the southern half of the county the drift is generally of shallow depth, rock being entered frequently at 30 or 40 feet, or even less. In the northern half of the county the thickness is much greater. The few bor- ings of which records were obtained indicate that it may averag'e not less 698 THE ILLINOIS GLACIAL LOBE. than 200 feet. The elevation of the northern portion is greater than tlie southern, but not so much as the difference in the thickness of drift, being- perhaps 50 or 75 feet g-reater. In the northern half, where the drift is thick, the sti-ucture is similar to that of Iroquois County, which borders it on the north; there being a soft blue till about 100 feet in thickness along the moraines, and of somewhat less depth on the narrow plains between them. Beneath this till tliere is frequently a black muck or soil, under which a harder till sheet sets in. In places the lower portion of the drift is sand or gravel instead of hard till. In the southei-n part of the county, where the drift is comparativelv thin, it consists of soft till similar to the surface portion in the district to the north. The older sheets of drift are apparently present only in thin deposits. Many flowing wells have been obtained in the valley of Middle Fork, near Potomac. J. M. Crayton, in a letter addi-essed to the Director, February 3, 1897, reported that within a square mile in the vicinity of Potomac there are over 200 flowing wells, varying in depth from 65 to 140 feet, each throwing a continuous and never-failing 2-incli stream of j^alatable water. The water is obtained from beds of sand below blue till, and there are tln-ee or more water-bearing beds, separated by thin beds of till or clay. The wells situated on low tracts between morainic ridges in this county have generally a strong hj^drostatic pressm-e, with head but a few feet lielow the surface. The absorbing area is, in all probability, on the neighboring- moraine. The sheets of drift are usually so arranged that water absorbed by a moraine may readily pass northward beneath the neighboring- till plain. In the southern portion of the county there is also some rise in tlie wells, especially if made on slopes north of the moraines. The wells there ai'e, however, shallower than in the northern portion of the county, and condi- tions are, on the whole, less favorable for obtaining flowing wells. INDIVIDUAL WELLS The ])ublic water supply of Hoopeston is from a well 350 feet in depth, which enters rock only 50 feet. The upper 30 feet of the drift is clay and sand, the remainder principally gravel. The well is only 8 inches in diameter, yet in 1895 it had an estimated capacity of 2,000,000 gallons a day. 'I'lie liead is about 20 feet Iw'low tlie surface. The water is inod- erately liard, and has a small amount of sulpliate of sodium and a still smaller amount of sulphate of magnesium, l)ut is very palatalilc The WELLS OF VERMILION COUNTY . ILLINOIS. 699 Manual of American Waterworks (1897) reports two 8-inch driven wells at the waterworks. Many wells are obtained in the vicinity of Hoopeston at depths of 80 to 100 feet, in sand or gravel below blue till. At East Lynn wells are usnally obtained at depths of 40 to 60 feet, in gravel or sand below a sheet of till. At Rossville a coal boring about 500 feet in depth entered hard rock at 190 feet. There is 125 feet of blue till forming- the upper part of the drift, beneath which is 60 feet of cemented material, called by the driller a soft sandstone, under which there is a water-bearing gravel resting on the rock. A similar cemented material was penetrated in a boring about 5 miles north of Rossville. It sets in under the blue till at a depth of 150 feet, and is underlaid by a yellow, pebbly clay, extending to the rock at 235 feet. The Manual of American Waterworks reports that the public supply at Rossville is from a deep well. The public water supply for the city of Danville is pumped from the North Fork of Vernjilion River. Wells in the city usually enter rock at a depth of about 15 feet and obtain water at a depth of 60 to 75 feet, which is near the level of the Vermilion River. A deep well sunk at Dan- ville Junction to a depth of 2,008 feet has the following section, reported by J. Gr. English, of Danville: ' Section of a well at Danville Junction, Illinois. Feet. Yellow till and gravel 20 Blue till 15 Hardpan 30 Blue till '. 15 Sandy loam 10 Clay, sand, and gravel 1 50 Muck bed -svitli wood • 8 Tough blue clay - 25 Sand and gravel 2 Coal Measures and Devonian strata 950 Hard gray limestone (probably Upper Silurian). 51 Soft gray limestone with H:S gas 10 Limestone, both dark and light colored 160 Soft white limestone with US gas 12 Limestone, both dark and light colored 342 AVhite sandstone (St. Peterf), and brackish water 35 Clay shale 110 Gray limestone 125 Blue limestone - 65 Blue shale 57 Eed rock 15 Total depth 2,008 700 THE ILLINOIS GLACIAL LOBE. A well near tlie waterworks in the Vermilion Valler penetrated to sup230sed Upper Silnrian limestone, which it enters at a deptli of 1,075 feet. Tlie thickness of drift at the Danville Junction well much exceeds that of other wells in the neighborhood, and indicates that a preglacial valley was entered by the boring. At Fithian, in the western part of the county, wells are usuallv obtained from sand or gravel associated with the till at depths of 50 feet or less, but one well was found to have a depth of 90 feet, of whicli the lower 15 feet is in rock. At Fairmount rock is entered, at slight depth, and wells usually are obtained at less than 50 feet. At Indianola wells are obtained from sand or gravel below till at a depth of about 30 feet, a strong supply of water being found at this depth. At the village of Ridge Farm the wells are usually obtained at a depth of 20 feet or less, in sand associated with till. The flowing- wells near Potomac, in the north part of the county, referred to above, usually penetrate the following- series of drift beds, the section being furnished by George Piatt, a well driller who has sunk sev- eral of the wells : Generalized section ofjioiriny irells near Potomac, Illinois. Feet. Yellow pebbly clay (Wisconsin) 10- 12 Blue clay, soft like putty, and containing few pebbles (^Wisconsin) 60- 70 Hard, stony clay, or ferruginous crust 1- 3 Sand and gravel, witb artesian water 6- 10 Hard, partially cemented, sandy clay 25- 30 Sand and gravel, with artesian water 5 1 lard, partialU' cemented, sandy clay •. 1.5- 20 Sand and gravel, with artesian water several feet Very few records of deep wells were obtained in this couutv outside the villages just discussed. The record of a farm well, made in sec. 31, T. 23, R. 13 W., shows 240 feet of drift, mainly till of a blue color, at the bottom of wliicli water was obtained in sand and gravel. A well in sec. 3G, in the same township, penetrated drift a deptli of 160 feet without reaching rock, and a well near Alviu a deptli of 173 feet. WELLS OF CHAMPAIGN COUNTY, ILLINOIS. ■ 701 CHAMPAIGN COUNTY. GENERAL STATEMENT. Champaign County is situated west of Vermilion, aiid has an area of 1,000 square miles, with Urbana as the county seat. The eastern and northeastern portions are tributary to the Vermilion River. The southern portion contains the headwaters of the Embarras and Kaskaskia rivers, and the northwestern portion is crossed by the Sangamon River. Much of the surface is so level that artificial ditching has been necessary to give good drainage. There are, however, two morainic systems crossing the county. The outer belt of the Bloomington system crosses the northeast corner, while the Champaign morainic system traverses the county in a southeast course, a little to the south of the center. The latter system consists of tlu-ee dis- tinct ridges in the southeast part of the county, which become united into a single ridge near Champaign, and continue united to southeastern McLean Countv, beyond which the morainic system is not traceable. The belt belonging to the Bloomington system has an ave:;ige relief of about 50 feet above the plain bordering it on the southwest. The Champaign morainic system has even less average relief above the bordering plains. In the portion of the county southeast from Urbana the drift has an average thickness of scarcely 100 feet, but throughout the remainder of the coiTuty its thickness is much greater. Records of 22 borings which did not reach rock show an average of 171 feet, and it is probable that the average for the county is not less than 200 feet. The drift to a depth of about 100 feet is, in the main, a soft blue till of Wisconsin age. On the moraines the depth is correspondingly greater. Prof C. W. Rolfe, of the University of Illinois, reports that throughout much of the county wells are found to pass through a buried soil immediately below the blue till, and then to enter a harder till. The writer found exposures, of which desci-iption has already been given (p. 216), of a peaty muck or soil along the bluffs of the Sangamon River in the western part of the county. Many wells have been sunk through the blue till into beds of sand or gravel associated with the underlying harder till, as shown in the discussion below. Throughout much of the county the wells have strong hydrostatic pressure, though they seldom overflow. 702 THE ILLINOIS GLACIAL LOBE. INDIVIDTAL ^VELLS. In the \acinity of Ludlow, in the north part of the countv, at an ahitude about 800 feet above tide, several wells have been sunk to a depth of 150 feet without reaching rock. They are largely through till. A well at F. Delaney's near Dickerson, in the northwest part of the countv, at an altitude about 750 feet above tide, reached a depth of 280 feet without encountering rock. In the vicinity of Rantoul the wells range from 80 to 200 feet in di-ift. The public water supply for this village is obtained from a well 135 feet in depth, mainly through blue till. A prosjDect boring for coal at this village, reported in the Geology of Illinois, is said to have reached rock at a depth of 80 feet. The report, however, is based upon rather imperfectly sup- ported data, the results of the boring having been kept secret for about twelve years before they were communicated to the Survey.^ Near Gilford, in the northeast part of the county, on the crest of the outer ridge of the Bloomington morainic system, a well is reported to have reached a depth of 260 feet and little or no rock was penetrated. No more definite record of the well was obtainable. In the vicinitv of ]\Iavview several wells have been obtained in sand and gravel below till at depths of 80 to 100 feet. A well at the residence of T. Hissong in Mayview reached a depth of 118 feet. The cities of Champaign and Urbana have a common public water supply obtained from seven wells sunk to depths of 157 to 162 feet in the glacial drift. The combined daily capacity of tlie wells is nearly a million gallons. The wells range in diameter from 5 to 8 inches. Two coal bor- ings at Urbana show a difterence of 165 feet in the distance to rock, one enteriny- rock at 100 feet, the other at 265 feet. The tbift section of the deeper one, furnished by Prof C W. Rolfe, appears on page 235. At Champaign a deep boring prospecting- for coal and gas, as indi- cated in the section on page 234, has penetrated a deposit of drift even thicker than in the deepest boring at Urbana, it being 300 feet, but the altitude is aljout 30 feet higher than at the Urbana boring, thus giving the rock surface nearh' tlie same altitude at l)()tli })laces. At .Sidne\' the duy wells are about 30 feet and bored wells 30 to 70 'Geology of Illinois. Vol. IV, p. 274. A¥ELLS OF PIATT COUNTY, ILLINOIS. 703 feet in depth, water being obtained in beds of sand and gravel associated with till. A prospect boring for coal at this village entered rock at 95 feet. The section of the drift penetrated appears on page 236. In the vicinity of Homer wells are usually obtained at about 30 feet, and rock is entered at 90 feet. South from Homer, near the southeast corner of the county, wells are usually obtained at 20 to 40 feet, but occa- sionally reach a depth of lOO feet without entering rock. At the village of Philo, which is situated on the crest of one of the ridges of the Champaign system, a well reached a depth of 171 feet with- out entering rock (see p. 235). Several wells in the vicinity of Philo reach a depth of 100 feet without entering rock. At Mahomet several wells obtain water at 45 to 50 feet. A well in this callage at D. McArtlmr's has the following section: Section of McArthur well at Mahomet, Illinois. Feet. Gravel <■ 7 Pebbleless clay 3 Browu mid gray till - 32 Black muck 2 Hard till 58 Total depth 100 A well at Jonas Lester's, a half mile south of Mahomet, passes tlu-ough a black soil below till at about 36 feet. The section of an exposure in the Sangamon bluff south from Mi-. Lester's appears on page 216. A well at George Frankenburgher's, 2 miles east of Mahomet, at an altitude 60 feet higher than the village, reached a depth of 200 feet with- out entering rock. About 4 miles southwest from Mahomet, on ground no higher than the village, records of three wells were obtained which penetrate over 200 feet of drift, mainly blue till, without entering- rock (see pp. 219-220). PIATT COUNTY. GENERAL STATEMENT. Piatt County is situated in the east-central part of the State, immedi- ately west of Champaign County, and has an area of 440 square miles, with Monticello as the county seat. The Sangamon River leads southwest- ward through the central portion of the county, and is the onl3^ stream of 704 ' THE ILLINOIS GLACIAL LOBE. importance within its limits. Mnch of the county has a very level surface which requires artificial di'ainage. Tlie few borhig-s of which records were obtained indicate that the county is covered with a very thick sheet of drift, averaging probably more than 200 feet. The greater part of the drift appears to be blue till. Shal- low wells of moderate streng'th are often obtained at depths of 25 to 40 feet, but tubular wells are usually sunk to depths of 100 feet or more and obtain stronger supplies than at shallow depths. INDIVIDUAL WELLS. At Monticello the public water supply, as noted on page 220, is from two wells 212 and 316 feet in depth, neither of which entei's rock. At Bement the public water supply is obtained from two wells, one 138 feet, in gravel below till, the other 225 feet, in rock the lower 3 feet. The shallower one obtains the larger supply of water. The Wabash Railway has a strong well at this village 152 feet in depth, from gravel below till. A well at the mill, 141 feet in depth, is also in gravel below till. Joseph Rodman sunk a well to a depth of 384 feet, which entered rock at 205 feet. A well at the Bement cemetery, 2 miles north of the village, at an altitude about 45 feet higher, reached a depth of 221 feet without entering rock, and a well one-half mile east of the cemetery, 222 feet in depth, did not reach rock. At Cerro Grordo several wells have been sunk to a depth of about 1^0 feet without reaching rock. The}^ are mainly through blue till, and in some cases are rather weak. A well near Mansfield, on the farm of Mrs. R. Carson, as noted on page 234, reached a depth of 200 feet without entering rock, mainly, through sand. DE^A^ITT COUNTY. GENERAL STATEMENT. Dewitt County is situated in the central part of the State, west of the northern portion of Piatt Countv, and south of McLean County. It has an area of 405 square miles, and Clinton is the county seat. Salt Creek, a tributary of the Sangamon River, leads westward through the central por- tion of the county, and is the main stream within its limits. The western WELLS OF DEWITT COUNTY, ILLINOIS. ' 705 part of the county is traversed by the outer moraine of the Wisconsin drift sheet, which here has a relief of nearly 100 feet above the plain to the west, but rises only a few feet above the plain to the east. The drift of this county, like that of the neighboring- counties, Piatt and McLean, is very heavy, averaging- probably more than 200 feet. The upper 100 feet is mainly a blue till, except on the plain outside the Wiscon- sin drift, where much sand and gravel occiu-s. The few deep wells sunk on the newer drift indicate that the sandy drift continues eastward under the Wisconsin drift sheet. In several places buried soils, or muck beds, have been found about the leVel of the base of the Wisconsin drift. There are also numerous instances of inflammable gas from beds of sand and gravel in the drift. INDIVIDUAL WELLS. But few records of wells have been obtained in this county, and these are of considerable depth. Wells are often obtained at moderate depths in sand or gravel associated with the blue till. At Farmer City the public water supply is from a well 176 feet in depth, which terminates in sand. The head is now a few feet below the surface, but when first made the well ovei-flowed. A prospect boring for coal at this town entered rock at a depth of 189 feet. The upper half of the drift is mainly till, the lower half largely sand and gravel. (See section on page 216.) A well one mile noi-th of Parnell, 200 feet in depth, did not enter the rock. At Clinton strong wells are obtained from sand and gravel below till at depths of 80 to 110 feet. The public water supply is obtained from several wells about 110 feet in depth. The following detailed record of the drift penetrated at Clinton, in a prospect boring for coal, made with a diamond di-ill, is taken from the Geology of Illuiois:^ Drift heds in a prospect boring for coal at Clinton, Illinois. Feet. Surface soil 5 Quicksand 15 Saud with gravel aud bowlders 17 Sand and clay mixed 53 Hardpan 12 Gravel '. 1 1 . Hardpan ...^ 4 > Vol. VIII, p. 34. MON XXSVIII 45 706 THE ILLINOIS GLACIAL LOBE. Feet. Clay and sand i Gravel and clay 7 Hardpan 3 Clay and sand 7 Clay and gravel 14 Clay 4 Hardpan 6 Clay and gravel 8 Quicksand 5 Sand and gravel 2 Coarse gravel 2 Clay 6 Gravelly hardpan 25 Quicksand 6 Sand and clay 7 Gravel 9 Sand 11 Gravel 9 Sand 9 Quicksand and gravel 101 Total depth (if drift 352 This boring' continued to a depth of 942 feet without reaching the bot- tom of the Coal Measures. A boring about one-half mile farther north was carried to a depth of 539 feet and penetrated only 270 feet of drift, or 70 feet less than that whose section is just given. The section of a gas well at James Barnett's, 8 miles west of Clinton, also reported in the Greology of Illinois, appears on page 205. It is stated that dry sand and pebbles were thrown out upon the surface by the pressure of the gas which was struck at the bottom of this well. In the -sacinity of Hallsville several gas wells have been obtained from beds of gravel between sheets of till at a depth of 117 to 127 feet. The gas is used in some cases to supply light and fuel for dwellings. At Kenney, on the low plain outside the Wisconsin drift sheet, at an altitude only 650 feet above tide, a boring was sunk to a dejstli of 291 feet, mainly through sand and gravel, without reaching the rock. At Waynesville, in the northwest comer of the count}-, on the outer slope of the moraine which marks the limit of the Wisconsin drift, the public water supply is obtained from wells 150 feet in depth.^ In the vicinity of Wapella wells seldom obtain a good supply of water at less than 65 feet, and several are 80 to 100 feet iu depth. They penetrate only 8 to 12 feet of surface silt and yellow till before entering blue till. ' See Manual of American Waterworks, 1897 WELLS OF LOGAN COUNTY, ILLINOIS. 707 The blue till extends to about 80 feet. At this depth a black mucky soil containing wood is found, which is underlain by a green clay, apparently a swamp subsoil. The muck and associated green clay are often several feet in thickness. They rest upon a harder till than that which overlies them. Occasionally gas is struck in sand near the level of the buried muck, but not in sufficient amount to be utilized for fuel. LOGAN COUNTY. GENERAL STATEMENT. Logan County is situated in the central part of the State, with Lincoln as the county seat, and has an area of 620 square miles. It is drained by Salt Creek and its tributaries, the principal tributaries being Sugar Creek, Kickapoo Creek, and Lake Fork. With the exception of the northeast corner, it lies outside the limits of the Wisconsin drift and its drainage sys- tems are much more mature than those on the Wisconsin di'ift to the east, though the elevation is about 100 feet lower than on neighboring portions of the Wisconsin drift. In addition to a better drainage system, there is a coating of loess, which absorbs the excess of rainfall much more rapidly than the till which forms the surface of much of the Wisconsin drift, and returns the moisture to the crops in seasons of drought to a larger extent than the till sheet. The thickness of di'ift is known only at a few points in the southwest part, where it is 60 to 100 feet. The thickness in the northern and eastern parts of the county apparently averages at least 150 feet, several wells having reached that depth without entering rock. The drift in the south- ern and eastern portions of the county is largely till, but in the northwestern part it apparently consists in the main of sand and gravel, thus resembling the diift of Mason County, which borders it on the west. Wells are usually obtained at depths of 20 or 30 feet, which have sufficient strength to supply stock as well as households. In a few cases, however, wells have been sunk to depths of 100 or even 200 feet. INDIVIDUAL WELLS. The village of Atlanta, which is situated on the outer moraine of the Wisconsin drift, obtains its supply for the waterworks from a well 151 feet in depth, a section of which appears on p. 206. In the vicinity of Atlanta 708 THE ILLINOIS GLACIAL LOBE. several wells reach a depth of 125 feet, and occasionally a well is sunk to a depth of fully 200 feet without entering rock. The well di-illers report that the upper 100 feet is a softer clay than the lower 100 feet. A buried soil is not uncommon at the base of the soft clay. It is probable that the soil immediately underlies the Wisconsin drift, though it may in some instances be at a lower horizon. At Lawndale, situated on the plain immediately outside the Wisconsin drift sheet, at an elevation about 115 feet lower than Atlanta, several wells have been sunk to depths of 65 to 80 feet, mainly through a hard till. Water is found beneath a cemented gravel in a loose gravel or sand. East from this village wells are in several instances 50 or 55 feet in depth, and enter gravel below till. At Hartsburg the public well is obtained in sand below till at a depth of 95 feet. Another well in the village is thought to have struck rock at about 100 feet. In the vicinity of Emden, on the plain outside the Wisconsin drift, in the north part of the county, tubular wells are 85 to 200 feet in depth with- out entering rock. They usually penetrate alternations of till with sand or gravel beds. Well drillers report that west from Emden the wells frequently penetrate a dry gravel to depths of 90 to 115 feet. Southwest from Emden a sand and blue silt frequently constitutes almost the entire section to a depth of at least 100 feet. A well at Mr. Hubbard's, in sec. 31, T. 21, R. 4 W., 196 feet in depth, has the following section: Section of the Hubhard well in Sec. 31, T. 31, R. 4, W. Feet. Yellow clay, mainly loess 16 Blue clay, nearly jtebbleless, called "blue mud" Ij50 Hard blue clay (till?) 30 Gravel at bottom. Total depth 199 At Lincoln a strong supply of water is obtained from sand at about 65 feet after penetrating beds of clay, sand, and gravel. The public water supply is mainly obtained by pumping from neighboring- creeks, though wells have been used. In the \acinity of Broadwell the drift is nininlv a blue till and is 60 or 70 feet in depth. Wells are frequently obtained above the blue clay at. depths of 15 or 20 feet. WELLS OF MENAKD COUNTY, ILLINOIS. 709 At Elkhart the drift is about 60 feet in depth, as follows: Generalized section of drift at Elkhart, Illinois. Feet. Loess aud slightly pebbly clay -- 12 Black soil containing wood ; 3-6 Yellow till . - - 5-10 Blue till 30-35 Records of several wells were obtained west from Elkhart which show a section similar to the above and enter rock at about 60 feet. At Mount Pulaski the public water supply is from a well about 80 feet in depth, which is mainly through a sandy drift. The villag'e stands on a knoll, about 40 feet above the bordering- plain. On the plain near Mount Pulaski a black mucky soil is penetrated below yellow clay at a depth of 16 or 18 feet, and wells are obtained at about 30 feet. A prospect boring for coal on the plain near this village penetrated 92 feet of drift. MENARD COUNTY. GENERAL STATEMENT. Menard County is situated in the central part of the State, immediately west of Logan County and south of Mason County. It has an area of only 320 square miles, and Petersburg is the county seat. The county is trav- ersed nearly centrally in a south-to-north direction by Sangamon River, and this stream also forms a portion of the north boundary of the county. The remainder of the north boundary is formed by Salt Creek, the princi- pal tributary of Sangamon River. The county is well drained by these streams and their tributaries, and has also a coating of loess which absorbs the rainfall rapidly and returns it to the crops in seasons of drought. The drift has about the same constitution as in southwestern Logan County, being largely a hard blue till. Its depth is seldom less than 60 feet, and probably averages at least 100 feet. Wells are usually obtained at about 35 feet, though a few have been sunk to greater depths. Borings for coal have tested the thickness of the drift at several points. INDIVIDUAL WELLS. The public water supply at Petersburg is obtained from four 8-inch wells sunk to depths of 35 to 60 feet in the glacial di-ift. A coal shaft in the Sangamon Valley, 2 miles north of this city and at about 65 feet lower elevation, entered rock at 46 feet. 710 THE ILLINOIS GLACIAL LOBE. In the vicinity of Greenview the drift is less than 100 feet in thickness. The loess has a depth of 12 to 16 feet, and is separated from the underlying till by a definite soil horizon. The record of a boring- at Sweetwater, published in the Geology of Illinois, is as follows: Section of a boring at Sweetwater, Illinois, Feet. Brown clay 40 Sand 11 Blue clay 59 Total drift 110 Black soil at bottom of drift. Another deep boring reported in the Geology of Illinois, is in a valley in sec. 2, T. 17, R. 6 W., which reached a depth of 86 feet without entering rock. Wood was found at 65 feet. Outcrops of rock occur in the west part of T. 18, R. 5 W., along ra^'ines at a level only 35 feet below the neighboring uplands, and wells east from there near the county line enter rock at about 70 feet. . CASS COUNTY. GENERAL STATEMENT. Cass County is situated on the east side of the Illinois River, immedi- ately south of the mouth of the Sangamon River, with Virginia as the county seat, and has an area of 360 square miles. It is drained by small streams tributary to the Sangamon and Illinois, and its drainage is much like that of Menard County, rainfall being disposed of by the loess as well as by a well-developed drainage system. There ai-e extensive bottom lands along the Sangamon and Illinois rivers, occupying about one-third the area of the countv. These bottoms have a sandy deposit, though usually their soil is productive. Wells at Beardstown indicate that the Illinois Valley has a filling of at least 100 feet, mainly sand and gravel. On the uplands the drift thickness is known to the writer at only two points — Ashland and Virginia — being 85 feet at the former and 187 at the latter vfllage. Wells are usually obtained at 25 to 50 feet, both on the bottom lands and on tlie upland. The shallower ones obtain their supply above tlie lilue till, but tlie deeper ones on the uplands enter that deposit n few feet. WELLS OF SCHTTYLEE COUNTY, ILLINOIS. 711 INDIVIDUAL WELLS. The public water supply at Beardstown is obtained from driven wells about 80 feet in depth. The wells show a gradation downward from sand through fine gravel to coarse gravel. Several artesian wells have been sunk at this city which penetrate about 100 feet of drift and reach depths of 1,050 to 1,100 feet. A flow of water is obtained f'om strata supposed to be Devonian at about 350 feet, and another flow with small amounts of gas and oil at 500 to 600 feet, and a third flow from near the bottom. The wells are estimated to have a capacity of about 175 gallons a minute. At Virginia wells are usually obtained at 25 to 50 feet from sand and gravel below clay. The beds of sand and gravel are not certain to occur, and only those wells which are so fortunate as to strike them obtain an abundant supply of water. Dr. J. F. Snyder, of Virginia, reports that during the drought of 1894 and 1895 about 70 per cent of the wells in the vicinity of Virginia became dry. The coal shaft at this village, 220 feet in depth, penetrated 187 feet of drift. It was mainly through till, but a black soil was passed through at 67 to 70 feet. This coal shaft is stated by Dr. Snyder to have afforded, during the drought referred to above, about 375 baiTels of water a day. A boring at Virginia 730 feet in depth obtained a water sti'ongly impregnated with sulphur and iron, which is considered unfit for general use. A remarkable thickness of peat was penetrated by a well at Mr. Oldi'idge's, in this village, of which an account appears on a previous page (p. 127). The section at Ashland has also been discussed (p. 127). SCHUYLER COUNTY. GENERAL STATEMENT. Schuyler County is situated on the west border of the Illinois River, northwest from Cass County, and has an area of 430 square miles, with Rushville as the county seat. Crooked Creek crosses its northwest corner and forms a portion of the western border. No other prominent sti-eam occurs in the county, but it has a somewhat mature drainage system, and portions of the county are very much broken by ravines. There is a loess coating, as in the counties east of the Illinois River, which adds to the ready disposition of the rainfall. The Illinois bottoms lay mainly east of the 712 THE ILLINOIS GLACIAL LOBE. river opposite this county, but extend about 2 miles into the county near the south border, above the mouth of Crooked Creek. The di-ift deposits appear to be much thinner than in the counties east of the Ilhnois, just discussed, rock being entered in many places at a de2:)th of about 30 feet. The wells are usually obtained above the rock at depths of 15 or 20 feet. INDIVIDUAL WELLS. At Rushville the present public supply is from impounded water fed by springs. From 1894 to 1896 a well 2,500 feet in depth supplied the waterworks. The quality of the water was found so unpleasant that its use was discontinued. The distance to rock varies 50 feet or more within the limits of this town. At the creamery rock was entered at only 20 feet, but at the northeast corner of the public square a well reached a depth of 70 feet without entering rock. A coal mine on the outskirts of the town enters rock at about 40 feet. The drift is mainly sand and gravel, while in the well at the public square it is mainly till. East from Rushville, in the vicinity of Pleasant View, wells are reported to enter a blue shale at de]3ths of 17 to 24 feet, but as some of them are also thought to enter gravel below this material it is probable that the material is till rather than shale. These wells enter limestone at about 60 feet, and this probably represents the thickness of the drift. In the interior of the county, northwest from Rushville, wells are found to enter rock at depths of 30 to 50 feet, though occasionally a greater depth is reached without encountering rock. BROWN COUNTY. GENERAL STATEMENT. Brown County is situated on the west border of the Illinois River, immediately south of Schuyler, and has an area of 300 square miles, with Mount Sterling as the county seat. Crooked Creek forms a portion of the northern border and receives the drainage of the northeast half of the county. McKee's Creek crosses the southern border of the county and drains its southwestern portion. In thickness and structm'e the drift in this county is similar to that of Schuyler. The surface also is generally much eroded and the drift is capped by a deposit of loess. The thickness of the WELLS OF ADAMS COUNTY, ILLINOIS. 713 loess is usually but 10 or 15 feet. On the borders of the Illmois, however, it attains iu one place a thickness of over 100 feet, a large part of the bluff being formed of that deposit. The Illinois bottoms occupy an average width of about two miles along the east border of the county, and the higher portions of the bottoms are sandy and gravelly, but the lower por- tions are covered with a deposit of muck. Although the drift is comparatively thin throughout much of the county, wells are usually obtained without entering the rock. The rock consists largely of a sandy shale, which often affords water in fair amount. INDIVIDUAL WELLS. At Mount Sterling the wells are usually obtained from sandy clay at depths of 16 to 25 feet. The Manual of American Waterworks states that the public supply is from an open well. In the vicinity of Mount Sterling shale is often struck at about 25 feet. The Illinoian drift embraces only about half this depth, there being 10 or 12 feet of loess at the surface. In the vicinity of Versailles wells are often sunk to a depth of 50 feet, and they are largely through loess. At Mound Station, in the northwest part of the county, a well at the lumber yard enters rock at 44 feet. The mounds or low hills immediately northwest of this station, which give it its name, are said to have a nucleus of rock which causes their relief of 50 feet or more above the plain. ADAMS COUNTY. GENERAL STATEMENT. Adams County borders the Mississippi River in the western part of the State, with Quincy as the county seat, and has an area of 830 square miles. The northern tliird of the county is drained westward tlu'ough Bear Creek, the southwestern part is drained westward through Mill Creek, and the southeastern part is drained eastward through McKee's Creek, a tributary of the Illinois River. In the western, central, and southern portions of the county there are several ridges of drift formed near the western border of the Illinoian drift sheet and trending in a general northwest-southeast direc- tion. These ridges are each a mile or less in averag-e width and rise 20 o to 60 feet above the bordering plains. Their distribution is shown on the 714 THE ILLINOIS GLAUIAL LOBE. glacial map, PI. VI. Aside from these few ridges, the drift has a plane surface and the drift filling is sufficient to nearly conceal preglacial valleys. With the exception of a narrow strip along the Illinois-Mississippi divide, in the central and northeastern parts of the county, the surface is generally much eroded. In the vicinity of the Mississippi bluffs there is a thick deposit of loess, in places reaching 50 or 60 feet, but within 5 or 6 miles back from the brow of the bluffs the thickness decreases to 10 feet or less. The loess affords quick absorption for the rainfall and supplies moisture to the crops in seasons of drought. The glacial drift is largely till. It is underlain in places by deposits of preglacial sand, first brought to notice by Worthen and later examined in more detail by Salisbury and the writer. The heaviest deposits noted are in the vicinity of Mendon, in the northwest part of the county, but deposits of considerable depth also occur along the Illinois-Mississippi divide in the southeast part of the county. In the former situation their elevation is 150 to 200 feet above the Mississippi River, and in the latter nearly 300 feet above that stream, or on about the highest rock surface known within the limits of the county. The thickness of the deposits and their relation to wells is set forth in the discussion below. The wells of this county are usually obtained at moderate depths in the drift. In nearly every township, however, several deep wells have been sunk. Records of 59 such wells were collected which show an average depth of about 63 feet. The rock was struck in 36 wells at an a%-erage depth of 61 feet. In the remaining 23 wells the average depth is 65 feet. From these wells it appears probable that the average thickness for the county is not less than 65 feet. None of the well records were obtained in the Mississippi bottoms, which occupy about 100 square miles of the county and in which the drift is probably more than 100 feet in average depth, for the valley floor of the preglacial river was cut to a level fully 100 feet below the present stream. INDIVIDUAL WELLS. The pulilic water supply for the city of Quincy is pumped from the Mississi])pi River, but there are numerous private wells in the city, ranging in depth from 90 to 200 feet. These wells are mainly through limestone. In parts of the city 30 feet or more of loess is peueti'ated before the lime- stone is entered. WELLS OF ADAMS GOUNTY, ILLINOIS. 715 At Mendon the public water supply is from a well 1,010 feet in depth, fi'om which water is pumped to a tank. This well passed through about 20 feet of loess and glacial drift, beneath which a deposit of orange- colored sand, presumably preglacial, was found, which extends to the lime- stone at 70 feet from the surface. Another well, at the public square, on ground 20 feet higher than the deep well, also penetrated a large amount of sand and entered limestone at a depth of 94 feet. Samples of this sand examined with acid are apparently free from calcareous material, thus differing markedly from the glacial sands of this region, which are com- posed largely of limestone fragments. The sand is also stained a deeper yellow than that associated with glacial drift. A well at W. W. Benton's, 1 mile west of Mendon, reached a depth of 400 feet, but the water supply is mainly from about 200 feet. The drift penetrated in this well is as follows, the determinations being made by the writer at the time the well was sunk: Section of Benton well near Mendon, Illinois. Feet. Loess 12 Gray gummy soil 2 Yellow sand 18 Gray gummy clay, apparently a soil 6 Gray sandy clay with few pebbles 35 Blue clay with, a few pebbles ; 10 Total 85 On ravines southeast of Mendon the following strata are exposed: . Section in a ravine southeast of Mendon. Peet. Loess 8 Black gummy soil-like clay _ 1_2 Sand .5_10 Gray sandy clay, resembling soil 1_2 Brownish clay or clayey sand with pebbles, of variable depth, and underlain by yellow sand, apparently preglacial 20-40 In the vicinity of Fowler, wells are usually obtained in the di-ift at depths of 20 to 40 feet, but a well at the mill was sunk to a depth of 262 feet and entered rock at 80 feet. At Coatsburg, a well at the mill reached a depth of 95 feet without entering rock. The drift is mainly till to a depth of 65 feet, beneath which there is a blue clay with sandy partings which is thought from the descrip- tion to be a water deposit. Waterworks recently constructed at this village 716 THE ILLINOIS GLACIAL LOBE. use a well for supply, but the depth is not ascertained. A coal shaft 1 mile east of Coatsburg, reported in the Geology of Illinois, passed through a clay similar to that at the mill in its lower portion, whicli was separated from the overlying- till bv a black soil, the following being the section, supplemented by notes taken bv the writer from the residents and from exposures near the coal shaft; it should be compared with the section given on page 62. Section in a boring for coal a mile east of Coatsburg, Illinois. Feet. Soil and yellow clay 6 Gray or ashy clay, resembling a soil *i Yellow till, becoming gray or blue near bottom 10-15 Bill -gray till 70-75 Black soil -- Si Strati tied clay 6 Tough blue clay 20 Total drift 118 At the Countv Infirmary near Coatsburg, a well entered rock at a depth of 165 feet. The upper 6.5 feet appears to be largely till, below which is a blue silt with sand partings, perhaps a water deposit. A boring at ]Mr. Henry's, near the infirmary, peneti-ated a similar section and entered rock at 160 feet. Another well on the infirmary farm is only 58 feet in depth. After penetrating about 40 feet of till it entered sand and gravel, which furnished the water. At Camp Point wells are usually obtained at 25 to 30 feet. A few have, however, been sunk to a depth of 45 or 50 feet, at which depth the first rock is struck. At Clayton rock is usually entered at a depth of 30 or 40 feet. The depth of wells supplying the waterworks has not been ascertained; the sys- tem was but recently introduced. At Liberty several deep wells have been sunk which show a range in thickness of drift from 47 feet to at least 90 feet. A well at Collins's mill, 90 feet in depth, has the following section: Section of a well at Collins's mill in Liherty, Illinois. Feet, Till, mainly of yellow color 50 Blue clay containing much wood, but with few pebbles 33 Sand with water 5 To ta 1 depth 90 A well in Liberty, at William Lytle's, after penetrating 52 feet of till, entered a sandv blue dav (•(int;iining wood. AVater was found in thi.s clay. WELLS OF ADAMS COUNTY, ILLINOIS. 717 A well at Mr. Grubb's, on ground 20 feet hig-her, entered Coal Measures shale at 47 feet. The drift is largely g-ravel. Mr. Grubb, who has had some experience as a well driller, reports that over an area of several square miles northwest from Libert}^ the till has a thickness of about .50 feet and is underlain bj a dark-blue clay similar to that of wells at Liberty and probably similar to that at the infirmary noted above. In a well exam- med by the writer while in process of excavation, a section of which appears on page 61, it was found that the dark-blue clay is a calcareous silt free from pebbles. In the vicinity of Burton wells are usually obtained at about 30 feet, near the base of the drift. Two wells southwest of the village reach a much greater depth and apparently strike into a preglacial valley. One at Mr. Dietreck's, on the east bluff of Mill Creek, has a depth of 200 feet and enters rock at 160 feet. A well at Mrs. Ihrig's, on the west bluff of Mill Creek, reached a depth of 155 feet without entering rock. It was mainlv through yellow clay to a depth of 105 feet, beneath which the clay is of blue color. Sand was struck near the bottom. In the vicinity of Newtown (Adams post-office) wells not infrequently reach a depth of 75 feet, there being a ridge of drift leading past the village in a northwest-southeast course, in which wells are sunk to a greater depth than on the bordering plains. The village well, 75 feet in depth, is reported to be mainly till with gravel at bottom. Another well on the ridge south- east of the Aallage, at the residence of Mrs. Wittemeyer, the section of which is given on page 59, passed through a gray muck or soil below till at 40 to 45 feet, which is about the level of the base of the ridge. Beneatli this soil was a sandy till grading into sand below, and water is obtained in this sand at 80 to 82 feet. At the village of Payson, which is located on a ridge of drift, rock is entered at a depth of about 90 feet, and the drift is largely of sandy consti- tution. A well at Mr. Barnard's, 1 mile west of this village, after penetrat- ing alternations of clay and gravel to a depth of 60 feet, passed into a reddish clay, apparently formed by the decomposition of limestone, which was 17 feet in thickness and extended to the rock. At Plainville the village well penetrates about 20 feet of clay contain- ing few pebbles, beneath which is ordinary till extending to the rock, which is entered at about 40 feet. The drift in that vicinity seldom exceeds 40 718 THE ILLINOIS GLACIAL LOBE. feet in depth, and wells are often sunk some distance into the underlying limestone. At Beverly the village well is 73 feet in dejjth, and apparently enters a preglacial sand in the lower 20 feet. This interpretation is made, how- ever, from the examination of a well in process of excavation about one- half mile east of the village, at the residence of J. Sykes, the section of ■vfhich appears on page. 60. Mr. Sykes's well penetrated an orange-colored quartz sand in its lower 15 feet, which is entirely free from calcareous material and is apparently much older than the glacial drift. It so happens that at this well there occurs at the base of the glacial drift a bed of gravel and sand which is highly calcareous, and is much fresher in appearance than the quartz sand just referred to, a feature which lends much support to the intei'pretation of the preglacial age of the orange-colored sand. Along the Illinois-Mississippi divide northwest from Beverly wells occasionally reach a depth of 90 feet without entering solid rock. They are reported to pass through an orange-colored sand in the lower part, which is probably similar to that examined in the well at Mr. Sykes's. Probably further study in the region would result in the discovery of natural expo- sures, for the ravines leading eastward from this divide are frequently cut to sufficient depth to reach the level of the orange-colored sand. PIKE COUNTY. GENERAL STATEMENT. Pike County is situated between the Mississippi and Illinois rivers, immediately south of Adams and Brown counties, and has an area of 795 square miles, with Pittsfield as its county seat. Fully three-foui"ths of the county is tributary to the Mississippi River. It is probable that a larger portion is now tributary to the Mississippi than in preglacial times. As noted on page 480, the headwater portion of Bay Creek leads southeast- ward, as if to join the Illinois, but a morainic ridge on its east border prevents its entering the Illinois, and it passes westward through a hilly region which probably once constituted the divide between the Mississippi and the Illinois, and thus becomes tributaiy to the Mississippi. The interior portion of the county is traversed by a series of drift ridges, which are the continuation of those noted in Adams County, and wliicli, like those of Adams Count\-, liave a noi-thwe.st-southeast trend. WELLS OF PIKE COUNTY, ILLmOlS. 719 Two of the ridg-es extend but little south of Pittsfield, but a third ridge, which, as noted above, follows the east border of Bay Creek, continues southeastward to the Illinois bluff, which it strikes between Montezuma and Bedford. These ridges constitute the highest land within the county, and reach in places an elevation of nearly 900 feet, and throughout much of their course are about 800 feet above tide. The rivers bordering- the county have an elevation of less than 450 feet above tide, or about 400 feet below the general level of these ridges. Much of the upland in the county stands nearly 300 feet above the bordering streams. Aside from the drift ridges justx mentioned, the drift of the county is a thin deposit, scarcely forming a continuous coating. But in the drift ridges a thickness of about 100 feet is in places attained, and the tliickness is seldom less than 50 feet. The di-ift in these ridges consists largely of a clay in which pebbles are less thoroughly intermixed than in typical till. The dumps of some wells examined, which reached the depth of 60 feet, show scarcely a handful of pebbles on their surface, while neighboring wells or natural exposures may contain a large amount of stony material. This imperfect intermingling of the stony and clayey material is probably due to the derivation of much of the drift from the immediate vicinity and the consequent short distance that it was transported. The loess forms a heavy deposit on the borders of the Illinois and Mississippi rivers, its usual thick- ness being 25 or 30 feet, but in the interior of the county its thickness decreases to scarcely 10 feet. On the higher portions of the drift ridges it is in places only 4 or 5 feet in depth. Along the drift ridges wells are often obtained without entering the rock, but elsewhere on the uplands strong wells are seldom obtained in the drift. In the valleys of the Mississippi and Illinois wells are usually obtained in sand and gravel at about the level of these streams. INDITIDTJAL WELLS. In the vicinity of Barry, in the northwest part of the county, the wells are usually obtained in rock at a depth of 60 to 85 feet. The loess and di'ift is 16 to 35 feet in depth. The public water supply is from a well 2,510 feet in depth, which has a head 135 feet below the surface, except when filled with surface water after an intermission from pumping. The water, unless diluted with surface water, is too salt for domestic use and the majority of the citizens depend upon private wells. 720 THE ILLINOIS GLACIAL LOBE. At the A-illag-e of Baylis, situated on the crest of the highest drift ridge in the county, a village well was sunk to a depth of 90 feet without enter- ing rock. The upper 30 feet is of a clayey constitution, the remainder a fine sand. Wells are obtained in this village at the top of this sand. In ra%'ines 1 to 2 miles southeast of Baylis there are exposures of drift about 50 feet in depth showing a brown surface clay with few pebbles, extending to a depth of 30 or 40 feet, beneath which there is a pebbh' brown clay, streaked with gray, exposed to a depth of 10 or 20 feet. On the west slope of the di-ift ridge, west and southwest from Baylis, the pebbly clay near the base of the ridge is more gravelly than on the eastern slope, perhaps because of the removal of the clayey material as an outwash from the ice sheet. The section of a well at the residence of A. Hill, 2 miles north of Baylis, appears on page 63. Along the county line northwest from Baylis the following section of drift deposits was found: Section at roadside on county line northicest of Baylis, Illinois. Feet. Loess or yellow silt 5 Ashy clay, probably soil 1-3 Yellowish-gray clay with few pebbles 40-50 Sand, gray or yellow, in thin beds 1- 2 Ash-colored clayey sand, resembling soil---. 2- 5 Cobble and gravel, with Canadian rocks 5-15 Total drift r 60-85 At New Salem a well near the railway station obtains water in a gi-avelly clay at a depth of 30 feet, but in the main part of the village wells usually enter rock at about 20 feet and obtam tvater at depths of 40 to 50 feet. In the vicinity of Griggsville the loess has a thickness of about 15 feet. Beneath it is a brown clay in which there are but few pebbles and which apparently extends to the rock. The village of Grig-gsAalle stands upon a slight elevation in which rock is nearly at the surface, but on the bordering plain rock is entered at greater depth, 25 to 35 feet. In tlie vicinity of Detroit and i\Iilton rock is occasionally entered at 30 feet, but wells along the drift ridge west and south from these villages are sunk to depths of 50 or 75 feet without entering the rock. A well at Marion Petty's, south of Milton, is reported to have passed through a black earth or soil containing wood at the base of the glacial drift, 30 to 35 feet from the surface. WELLS OF SOOTT COUNTY, ILLINOIS. 721 At Time the village well has a depth of 70 feet. For a distance of 50 feet it is tlirough a clay of brown color carrying few pebbles. The I'emain- der is through a blue clay of the consistency of putty. Eavines in that vicinity show about 20 feet of loess, beneath which is a slightly pebbly brown clay. A well at J. E. Dinsmore's, 2 miles south of Time, reached a depth of 60 feet, mainly through pebbly clay, and did not strike rock. Mr. Dinsmore made another well in a ravine at an elevation about 40 feet below the one at his residence which passed tlu-ough a black muck below brown clay at a depth of 40 to 45 feet and entered a red clay similar to the residuary clay formed from limestone in that vicinity It had not struck solid rock at a depth of 50 feet. At Pittsfield the public water supply is from a well 2,200 feet in depth, which is used for fire protection and street sprinkling only. Private wells are obtained at moderate depth in the rock, seldom more than 50 feet. On the drift ridges west from Pittsfield wells reach depths of 30 to 50 feet without entering rock, obtaining- their water from sandy drift associated with the clay. At Nebo, in the valley of Bay Creek, wells are obtained at only 15 or 20 feet in sandy beds at about the level of the creek. On the bordering uplands wells are sunk into rock to depths of 50 or even 100 feet. SCOTT COUNTY. GENERAL STATEMENT. Scott County has its west border on the Illinois River, opposite Pike County. Its area is but 250 square miles, and Winchester is the county seat. It is drained westward by tributaries of the Illinois, of which the principal ones are Mauvaise Terre and Big Sandy creeks. The Illinois bottoms occupy a strip about 3 miles in average width along the west border of the county. The uplands have a coating of loess, which is 25 to 50 feet in thickness on the border of the Illinois, but decreases eastward to scarcely more than 10 feet at the east line of the county. The drainage lines, together with the loess, dispose of the rainfall rapidly. In the Illinois River bottoms the sand is in places so light as to be barren in seasons of drought. The drift in portions of the county is very thick, there being along the Illinois bluffs wide stretches in which no rock is exposed, though the bluffs MON XXSVIII 46 722 IHE ILLINOIS GLACIAL LOBE. are over 100 feet in lieig-ht. But in portions of the county the drift is only 20 or 30 feet in deptli. The drift filHng is sufficient to greatly conceal the courses of preglacial tributaries of the Illinois. Till fonns the principal part of the drift, though in some parts of the Qounty wells pass through a large amount of gravel and sand. The wells are usually 20 to 40 feet in deptli and obtain water from the drift, very seldom entering the rock. INDIVIDUAL WELLS. In the vicinity of Winchester wells are usually obtained at a depth of 20 or 30 feet, but a well at the grist mill was sunk to a depth of 412 feet. It has a head 60 feet below the surface, or 470 feet above tide. In the vicinity of Manchester wells are obtained at a depth of 20 or 30 feet. A coal shaft enters rock at about 60 feet. In the vicinity of Alsey wells are obtained at about 40 feet. They penetrate 8 or 10 feet of loess, and then pass through till to the water- bearing bed at bottom. Near Glasgow, on the Illinois River bluff, wells usually pass through about 25 feet of loess, 20 feet of yellow till, and 30 feet or more of blue till before entering rock. In some cases they are obtained above the rock. MORGAN COUNTY. GENERAL STATEMENT. Morgan County is situated north and east of Scott County and touches the Illinois River for a few miles on its northwest border. It has an area of 680 square miles, and Jacksonville is the county seat. It is drained west- ward to the Illinois River through several creeks, of which Indian and Mauvaise Terre creeks are the largest. Like Scott County, this county has a heavy coating of loess on the border of the Illinois River, but only a thin deposit a few miles back from the Illinois The loess and drainage lines, as in Scott County, give excellent drainage. The drift is tliiii in the southeast portion of the county, rock being at depths of but 20 or 30 feet in many of the wells, but in the remainder of the county the thickness generally exceeds 50 feet and in places reaches at least 150 feet. It consists largely of till, but- gravel and sand beds are sufficiently abundant to supply water for most of tlie wells. The wells are sehhun sunk to de})ths of more than 40 or 60 feet. WELLS OF MORGAN COUNTY, ILLINOIS. 723 INDIVIDUAL WELLS. In the extreme northwest part of the county, on the llHnois bottoms, wells are obtained in sand at 30 to 50 feet, or at about the level of the Illinois River. On the bluffs they are sunk through 20 feet or more of loess before entering glacial drift. Rock is occasionally struck in that part of the county at about 40 feet, but wells usually obtain water above the rock. At Chapin the shafts or borings for coal pass through about 12 feet of loess, beneath which is a sheet of till extending- to the rock, which is entered at 40 to 50 feet. Wells in several instances have been sunk entirely throug-h the drift, but they usually obtain water at about 20 feet. At Jacksonville wells are usually obtained at 20 to 40 feet, but the public water supply is from two deep artesian wells, one of which is 2,373 and the other 3,028 feet in depth. The wells are situated on low ground, about 30 feet below the level of the Chicago and Alton depot, and water will rise a few feet above the surface. In the shallower well it is stated to rise 15 feet and in the deeper one 30 feet above the well mouth. Attention is here called to an error which appears in the present author's paper in the Seventeenth Annual Report, the head at the deep well being given as 30 feet below the surface, instead of 30 feet above. The drift at the artesian wells is about 140 feet in thickness and consists mainly of till. A boring for coal east of the city penetrated 154 feet of di-ift, mainly till, except about 10 feet of sand at the bottom. There is a series of drift knolls leading from Jacksonville southwest- ward 3 or 4 miles on which several wells have been obtained at dejDths of 40 to 50 feet. They are almost entirely through till, the lower half being a blue till. At Prentice a coal shaft penetrates 85 feet of drift, the greater part of which is a blue till. In the lower ten feet a sandy clay containing- a log was passed thi'ough. At Alexander wells are usually obtained at depths of 20 to 40 feet, but one at the elevator reached a dejDth of 95 feet and did not enter rock. Its section is as follows: Section oftoell at elevator in Alexander, lUinois. Peet. Loess 10 Yellow till 10 Blue till with thin saud beds 75 724 THE ILLINOIS GLACIAL LOBE. A well near Alexander, on the farm of Isaac Tyndall, was sunk to a depth of 1,000 feet without obtaining a flow. Another well was sunk to a depth of 320 feet. Each of the wells yields a small amount of gas, which is struck in Coal Measures strata. The drift at these wells is about 90 feet in depth, as follows : Section of drift in Tyndall well near Alexamder, Illinois. Feet. Soil and yellow clay - 25 Gray pebbly clay 26 Blue clay 25 Clays of variable color 15 Total drift 90 At "Waverly wells are 20 to 50 feet in depth, and the deeper ones enter rock near the bottom. The loess in that vicinity is only 6 feet in depth. The drift is mainly yellow till, though there is blue till near the base. In tlie vicinity of Franklin rock is usually entered at about 35 feet, but wells are often obtained above the rock. SANGAMON COUNTY. GENERAL STATEMENT. Sangamon County, situated near the center of the State, contains Springfield, the State capital, which is also the county seat. It has an area of 860 square miles. The northeastern portion of the county is traversed in a westward course by the Sangamon River, and this stream with its tributaries drains nearly all of the county. The drainage from the western and southern portions of the county is northeastward, there being a rapid descent in that direction. The county is well drained, and yet the valleys of most of the streams are very shallow. A coating of loess about 8 feet in average depth caps the glacial drift, and aids greatly in the ready absorption of the excess of rainfall. The drift is generally of moderate depth, the distance to rock being seldom more than 50 feet. Where it is mainly till, wells are frequently sunk into the underlying Coal Measures for Avater, the supph^ from the drift being weak. Tlie conspicuous development of Sangamon soil between the loess and till is discussed on preceding pages. WELLS OF CHEISTIAN COUlJTTY, ILLINOIS. 725 INDIVIDUAL WELLS. The jDiiblic water supply for the city of Springfield is obtained from infiltration wells sunk to a depth of about 25 feet on the banks of the Sangamon River. Private wells are largely discontinued, but may be obtained at depths of 25 feet or less. In the northwest part of the county, near Pleasant Plain, the drift is 60 to 80 feet in dejDth, as shown by coal shafts, but wells are usually obtained at 20 to 40 feet. In the northern part of the county the drift is 40 to 60 feet in depth, but wells are usually obtained without entering- the rock. In the eastern part several coal shafts and a few of the wells enter rock at about 60 feet. At Illiopolis rock is struck at 54 feet, and at Dawson at 60 feet. Southeast from Illiopolis, near the Sangamon River, records of two wells were obtained which penetrated about 80 feet of drift. In the southern part, near Lowder, although the altitude is the highest in the county, rock is frequently entered at about 20 feet. This area of thin drift is a continuation of that noted in southeastern Morgan County. In the western part of the county the distance to rock ranges from 20 to at least 75 feet. Near New Berlin the rock is entered at 40 or 50 feet. At Bates a well at the elevator, 70 feet in depth, did not reach rock. A well at the elevator in Curran also reached a dejDth of 70 feet without enter- ing rock, but within 2 or 3 miles south of Curran wells enter rock at 20 or 30 feet. CHRISTIAN COUNTY. GENERAL STATEMENT. Christian County is situated southeast of Sangamon and has an area of 710 square miles, with Taylorville as the county seat. It is drained chiefly by the South Fork of Sangamon River, which leads northwestward through the county. -The main Sangamon River forms the north border of the county. The character of the drainage and the coating of loess are similar to the same features in Sangamon Countj^ already discussed. The drift is seldom less than 60 feet, and in places is more than 100 feet in thickness, and consists largely of blue till. The occurrence of peat and muck at the base of the loess is quite common, as indicated on page 126. Tliroughout the county wells are usually obtained at depths of 20 to 30 726 THE ILLINOIS GLACIAL LOBE. feet. The data concerning' the distance to rock are obtained largely tlu'ough coal shafts and borings. INDIVIDUAL WELLS. At Mount Auburn, which is situated on a knoll in the north part of the county, wells penetrate a brown, sandy clay to a depth of about 30 feet before entering blue till. On the bordering plain blue till is found at 20 to 25 feet, but wells are usually obtained without entering it. The drift in that vicinity is at least 80 feet in depth. Near the center of the county, in the vicinity of Taylorville, wells are frequently found at depths of only 15 feet, in sandy beds at the base of the loess. In the city of Taylorville, however, they are usually sunk to depths of 20 to 40 feet. The public water supply is from an open well 30 feet in diameter and 30 feet in depth. The amount of water is so great in this vicinity that much difficulty is experienced in sinking coal shafts. The Taylorville coal shaft has the following section of diift: Section of drift in the Taylorville coal shaft. FeoL Surface clay 13 Sand and gravel 24 White clay 3 Black gummy clay 4 Bowlder clay 17 Sand aud gravel 15 Sand 15 Greenish clay 12 Clay and gravel 12 Sand aud gravel 11 Total drift 126 At Pana the coal shaft is reported by Worthen to have penetrated two buried soils, but the writer finds that his upper soil is simplv wood embed- ded in till. The lower is a black muck. The import of this section, together with similar sections at other points has already been discussed (p. 107 et seq.). The wells in this city range from 18 to about 50 feet in depth. The waterworks supply is from wells 45 to 48 feet deep, in part 3 inches and in part 6 inches in diameter. These wells afforded, during the season of drought ill 189,5, an average daily consumption of 215,000 gallons. A boring was sunk at this city to a depth of 2,507 feet, but found only a weak supply oi' brackish water after entering the rock. 9 WELLS OF MAOON COUNTY, ILLINOIS. 727 At Morrisonville the public water supply is obtained from large wells excavated to a depth of 25 or 30 feet. During the drought of 1894 and 1895 only about 300 ban-els a day could be obtained from this source, where fully twice that amount was needed. Mr. H. N. Herdman, chairman of the waterworks committee, estimates that private wells in the village have an average yield of about 10 barrels a day in seasons of drought. At Palmer a coal shaft penetrates 60 feet of drift, as follows : Section of coal shaft at Palmer, Illinois. Teet. Loess and yellow till 16 Hard gray till 22 Soft brown clay ^ Sand 10 Gravel 1 Pebbly clay 4 Total drift 60 At Miller Station rock is entered at about 60 feet, or at nearly the same elevation above tide as at Pana. The drift is largely gray till. MACON COUNTY. GENERAL STATEMENT. Macon County is situated in the central part of the State, with Decatur as the county seat, and has an area of 780 square miles. The Sangamon River traverses it nearly centrally from east to west, and there are no other large streams within the limits of the county. The greater portion of the county lies within the limits of the Wisconsin drift, the outer moraine formed at the Wisconsin stage of glaciation having a southward course through the western part of the county. The portion occupied by the Wisconsin drift stands about 100 feet above the plain on the west, but is far less perfectly drained. Not only are drainage lines less perfect, but the loess, which constitutes so important an absorbent for water in counties to the west, is absent or is represented only by a thin coating, probably drifted by the wind. The thickness of the drift is known at but a few points, and these, together with sections of deep wells which do not reach rock, indicate that the average thickness of the drift exceeds 100 feet. The Wisconsin drift consists largely of a soft blue till, readily distinguished from the harder t 728 THE ILLINOIS GLACIAL LOBE. gray or bine tills of the earlier sheets beneath it and Avhich extend over tlie country to the west. Tubidar wells are often sunk in the j^ortion of the county covered by the Wisconsin drift to a depth of 100 to 150 feet, and occasional! v to greater depths without reaching rock. A large number of wells, llowe^•er, are obtained from this drift sheet at depths of but 20 to 40 feet. On the jjlain outside the limits of the Wisconsin drift the wells are often obtained at but 12 to 15 feet, and tliey seldom exceed 25 feet in depth. INDIVIDUAL WELLS. At Niantic, on the plain in the western part of the county, wells are usually obtained in sand and gravel at a depth of 15 feet. A coal shaft at this village penetrates the following beds of drift : Section of drift beds in coed shaft of Niantic, Illinois. Feet. Soil and brown clay H Sand and gravel _ 4 Till of grayish color _ 25 Hard blue till 10 Soft clay 15 Hard gray till 10 Soft clay of brown color 7 Total drift ^2 At Hamstown, on the crest of the moraine east of Niantic and about 90 feet higher, several tubular wells have been sunk to depths ranging from 75 to 152 feet. The deepest, at the residence of Dr. John Connelly, has tlie following section : Feet. Yellow till 15 Soft blue till, about 100 Hard grayish-blue till 37 Gravel and water at bottom. Total 152 In several instances the wells near Harristown appear to obtain their supjily from the base of the Wisconsin drift, just below the soft blue till, at a depth of 100 to 110 feet. The few which are sunk deeper usually enter a harder till, as in the section just noted. East from Harristown, toward Decatur, the wells are often sunk to depths of 85 to 110 feet, mainlv through a soft blue till. The elevation is a few feet lower than on the crest of the moraine at Hamstown, and the wells probably reacli tlie bottom of the Wisconsin drift. WELLS OF MOULTEIE COUNTY, ILLINOIS. 729 The city of Decatur obtains its public water suppl}^ by pumping from the Sang-amon River. The city engineer reports that the wells of that city obtain their strongest supply of water at a depth of about 100 feet in beds of gravel below blue clay, and that the water from these -wells will rise within 20 feet of the top. He estimates the capacity of a good well to be about 20 barrels a day. Coal borings at Decatur, reported in the Geology of Illinois, enter rock in one instance at 110 feet and in another at 140 feet. The section of the air shaft, taken from the Geology of Illinois, which appears on page 204, indicates the variable structure of . the di-ift. .The shaft is located near the Sangamon River Ijluff. At Maroa, in the north part of the county, the strongest wells are about 100 feet in depth, in gravel below till. This village has waterworks, recently constructed, which obtains its supply from gravel at a depth of 85 to 100 feet. At the neighboring villag-e of Forsj^the several good wells are obtained at 35 to 45 feet. At Macon a well 120 feet in depth furnishes the public water supply. It terminates in gravel below a thick sheet of till, and the well is practically inexhaustible. Water rises within 60 feet of the surface, and it is stated by residents that the water rose to that level in less than five minutes after the water bed was struck. The well at Blue Mound from which the public water supply is pumped was sunk to a depth of 213 feet without reaching rock, mainly tln'ough a hard blue till. As this village stands on the plain outside the Wisconsin drift sheet, the great thickness of drift here ^jenetrated belongs to an earlier stage of glaciation. The principal part of the water is obtained within 40 feet of the surface, and wells in that vicinity are 15 to 40 feet deep. MOULTRIE COUNTY. GENERAL STATEMENT. Moultrie County is situated southeast of Macon, in the east-central part of the State, with Sullivan as the county seat, and has an area of 340 square miles. The Kaskaskia River crosses the southeastern part in a westward course, and most of the county is tributary to that stream. Much of the surface is flat and poorly drained, the county being situated within the limits of the Wisconsin drift, where drainage lines are generally immature. 730 THE ILLINOIS GLACIAL LOBE. The thickness of drift is known only at the village of Sullivan, where it is about 200 feet. Borings in neighboring counties also jDenetrate nearly as great an amount of drift. It therefore seems probable that the thickness at Sullivan is not much above the average for the county. Wells in this county enter a soft blue till at 10 or 15 feet, which, like that of the neigh- boring counties, Piatt and Macon, belongs to the Wisconsin drift. It prob- ably extends to the level of the plain outside the Wisconsin di-ift sheet, which is nearly 100 feet lower than the general elevation of this county. Few records of wells were obtained, though it was ascertained that wdiile wells are usually but 30 or 40 feet deep, not a few are sunk to depths of over 100 feet. INDIVIDUAL WELLS. At Sullivan the strongest wells are obtained at a depth of 100 to 125 feet in sand beds below till, and the waterworks are supplied from a well of this class. A coal boring at or near Sullivan, made by Mr. John Patterson, is reported to have struck a soft sandstone at about 200 feet, but a well boring at Sullivan, made by Mr. Patterson, is reported in the Geology of Illinois to have reached a depth of 210 feet without entering rock and to have terminated in sand below clay. Veins of water were struck at 15 feet, 105 feet, and 180 feet. The last vein struck has a head 15 feet below the surface. At Dalton there is a village well 110 feet in depth, which obtains its main supply from about 70 feet.^ Several wells in this vicinitv are 70 to 85 feet in depth and a few about 100 feet. They reach the base of the Wisconsin drift at about 65 feet, below which there is sandy material often associated with a black mucky soil. Beneath this sandv material is a harder till than the Wisconsin. The deepest wells in that vicinity are 150 feet, and none strike rock. At Bethany wells are often sunk to a depth of 70 feet before reaching a good supply of water. The Wisconsin drift here is only about 40 feet, beneath wliich there is a greenish clay associated with a black muck. This is underlain by a hard till, in which there are gravelly beds yielding water. The deepest wells are 140 feet and do not enter rock. 'The Manual of American WaterworUs (1897) reports that the public water supply at Dalton is obtained from a shallow well retiniriug a pump but 22 feet in length. This is evidently a mistake, since no wateiworks had been constructed or were contemplated at the time of my visit in June. 1897. WELLS OF DOUGLAS COUNTY, ILLINOIS. 731 DOUGLAS COUNTY. GENERAL STATEMENT. Douglas County is situated in the east-central part of the State, with Tuscola as the county seat, and it has an area of 410 square miles. Its western portion is crossed in a southward course by the Kaskaskia River, and the east-central portion by the Embarras River. The surface is gener- ally very level and imperfectly drained, except on the immediate borders of the streams just mentioned. A small drift ridge belonging to the Cham- paign system traverses the northeast part of the county, but it has a g-eneral relief of only 20 to 30 feet above the bordering plain. A similar. small ridge crosses the southeast corner of the county. The surface of these ridges is nearly as smooth as that of the bordering plains, and is imperfectly drained. The thickness of the drift in this county has been ascertained at but one point, Tuscola, where one well entered rock at 174 feet and another at 179 feet. But at Oakland, just across the county line, in Coles County, rock is entered at only 50 feet. The drift, like that of the counties to the west, just discussed, consists mainly of a soft blue till as far as wells have penetrated. Iia the wells at Tuscola the drift was in the main a blue till. Wells 60 to 75 feet in depth are common in this county, and a few have been sunk to depths of 100 feet or more. INDIVIDUAL WELLS. At Areola the public water supply is from wells about 50 feet in depth, and records of several wells were obtained in the vicinity of that village which have a similar depth. Two wells a few miles southeast of Areola are reported to have entered a swampy muck below blue till at about 50 feet, and beneath this a till was found harder than that above the muck. One well at Morris Bradford's reached a depth of 68 feet and one at E. Bradford's a depth of 75 feet. At Tuscola a deep well has been sunk with a view to obtaining artesian water for the waterworks, but at last reports the well was incomplete and waterworks had not been established.^ The wells in the vicinity of Tuscola are obtained at a depth of about 30 feet, but none are considered of suffi- cient strength to supply the waterworks. ' Manual of American Waterworks, 1897. 732 THE ILLINOIS GLACIAL LOBE. EDGAR COUNTY. GENERAL STATEMENT. Edo'ar Oountv is situated near the middle of the east boundarv of the State aud lias an area of 630 square miles, with Paris as the county .seat. It is crossed by no large streams, the di-ainage being entirely through small creeks. Those in the eastern part drain eastward to the Wabash, those in the western part are tril^utary to the Embarras, while the drainag-e of the southern portion is divided between the tributaries of the Embarras and small streams leading directly to the Wabash. The northern part of the county is occupied by the Champaign morainic system, while the southern portion is crossed by the Shelbvville morainic system. Between these morainic systems there is a verv flat area dotted with occasional low knolls or ridges of drift. South of the limits of the Wisconsin drift there is a low plain which touches the borders of this county and which is markedly more eroded than the more elevated plain north of the outer moraine, a feature which testifies to its long-er exposure to agencies of erosion. The drift of the moraines and the plain between them consists largelv of a soft blue till, thoug'h portions of the outer moraine have a gravelly constitution. The plain outside the outer moraine is underlain by a harder till than that forming the body of the moraine. It is also capped by a silt which is correlated with the loess, but the moraine and district to the north are nearly free from silt capping. The thickness of the drift along each of the moraines is 100 feet or more, but on the plain between the moraines rock is in places entered at 50 feet or less, the drift being much thinner than in counties to the west. The rock siii'face appears to be generally higher in Edgar County than in neigh- boring counties on the west. Wells are generally obtained in this county at depths of 20 to 40 feet and, so far as ascertained, A-ery few exceed 60 feet. Those which enter rock usually find water within a few feet. Tlie majority, however, obtain their supph^ above the rock. INDIVIDIAL WELLS. The public water supply at Paris is olnained from a well 60 feet deep, which terminates in gravel below till. The private wells in the city aud WELLS OF OLARK COUNTY, ILLINOIS. 733 vicinity are usually obtained at depths of 20 to 40 feet. A boring at Sanford, near the State line, east of Paris, whose section is given on page 201, entered rock at 147 feet. At Dudley wells are obtained at about 25 feet and are largely tln-ough a sandy drift. Between Dudley and Kansas and also to the north of the latter village wells are reported to have passed through a soil below till at 35 to 40 feet. At Kansas wells are usually 20 to 25 feet and occasionally 40 feet in depth. They are obtained in gravel below blue till. Good wells are esti- mated to yield about 30 barrels of water a day. Near Isabel wells occasionally reach a depth of 60 or 60 feet without entering rock. The majority of wells, however, are much shallower. A short distance east of Isabel rock is encountered at a depth of only 25 feet, and wells in the central and eastern parts of the county not infrequently enter rock at 25 feet or less. On the plain outside the Wisconsin drift wells are usually obtained at about 30 feet and seldom enter the rock. They are largely through a hard till. CLARK COUNTY. GENERAL STATEMENT. Clark County is situated on the eastern border of the State, immediately south of Edgar, a portion of its east border being formed by the Wabash River. It has an area of 510 square miles, with Marshall as its county seat. The eastern portion of the county drains directly to the Wabash, but the western half is drained southward through Hickory Creek, a tributary of the Embarras. The outer moraine of the Wisconsin drift covers a few square miles in the northwest corner of the county. Aside from this the drift of the county belongs to the earlier stages of glaciation. Although the surface was originally very level, drainage lines are sufficiently well developed to remove the surplus rainfall more rapidly than on the flat areas occupied by the Wisconsin drift. The drift has a capping of the compact phase of the loess, called white clay, whose depth is but 5 or 6 feet. As previously indicated, this clay is separated from the underlying till by a black soil. The drift of this county is largely a hard till which is brownish yellow at top, but changes to a greyish blue color at a depth of 15 or 20 feet. 734 THE ILLINOIS GLACIAL LOBE. Wells are usually of sufficient strength for household or farm use, but Mr. J. T. Lafferty, of Martinsville, an old i-esident of the county, states that the strongest wells seldom yield more than 10 barrels a day, and a large number will not afford more than one "barrel. Wells are us^ially obtained at a depth of 15 or 20 feet from pockets or thin beds of gravel or sand asso- ciated with the till. In portions of the county wells have been sunk to depths of 40 feet or more, and such wells usually obtain their supply from gravel below blue till. In the vicinity of Marshall, however, sandstone is entered at about 20 feet, and wells are obtained after penetrating it a few feet. INDIVIDUAL WELLS. The wells at Marshall which enter sandstone are estimated to yield, in some cases, 100 barrels a day, and many of them are but 25 feet in depth. In the vicinity of Martinsville a few wells have been sunk to a depth of 70 or 80 feet, but they are usually obtained at 15 or 20 feet. At Casey the deepest wells are about 100 feet, but the great majority are between 18 and 25 feet in depth. On the Wabash bottoms, in the southeast part of the county, wells are usually obtained at about the level of the river. On the higher terraces they need to be sunk 50 or 60 feet. They penetrate fine gravel or sand. COLES COUNTY. GENERAL STATEMENT. Coles County is situated in the east-central part of the State, with Charleston as the county seat, and has an area of 520 square miles. The Kaskaskia River passes southwestward across its northwest corner, and the Embarras River passes southward through the eastern part of the county. The greater part of the county is tributary to the latter stream, but is imperfectly drained, like the neighboring counties on the north and west already discussed. The Shelbyville morainic system crosses the southern part of the county in an east-to-west course, lea^'ing but a few square miles in the extreme southeast and southwest corners outside its limits. 'I'liis morainic system has a breadth of 5 or (> miles and a relief of 75 to 100 feet abo\n' the jjlain south of it. It stands only 30 to 50 feet above the plain on tlie north. WELLS OF COLES COUNTY, ILLINOIS. 735 The Wisconsin drift sheet in this county, as in neighboring counties already discussed, consists largely of a soft blue till, while the underlying sheet of drift is a harder till. Along the Embarras River there are expos- ures of the harder till beneath the Wisconsin drift, and this harder till is capped by a white clay, as in the disti-icts outside the limits of the Wisconsin di'ift. In the eastern portion of the county rock is occasionally entered at 45 to 50 feet, and is exposed extensively along the Embarras River in the southern part of the county. The thickness in the western half of the county is greater, being in places not less than 150 feet. Wells are usually obtained without entering the rock, .and in the western part of the county but few reach the bottom of the Wisconsin sheet of drift. INDIVIDUAL WELLS. At Oakland, in the northeast part of the county, the wells are usually about 20 feet in depth. But a well at the mill reached a depth of 120 feet, entering rock at 50 feet. Northwest from Fairgrange several wells have been sunk to depths of 60 to 120 feet without entering rock. They usually pass from a soft to a hard till at a depth of 50 or 60 feet. This is thought to be the depth of the Wisconsin drift sheet in that locality. At Charleston the waterworks are supplied b}^ pumping from the Embarras River. Wells are usually obtained from sand and gravel below till at a depth of 20 to 40 feet. A well in the northern part of this city reached a depth of 127 feet without entering rock, but a boring for oil made some years since is reported in the Geology of Illinois to enter rock at 55 feet. The section of drift is as follows : Section of boring at Charleston, Illinois. Feet. Soil and yellow clay 18 Sand and gravel 6 Blue clay 16 Bowlder clay 15 Total drift 55 At Mattoon the public water supply is obtained from sand and gravel below till at a depth of 60 to 70 feet. The private wells in this village are usually obtained at 15 to 30 feet. A coal boring is reported to enter rock at about 100 feet (see p. 202). 736 THE ILLIXOIS GLACIAL LOBE. At Lerna, which is situated on the crest of the outer moraine of the Wisconsin di'ift, wells have occasionally reached a depth of 100 feet with- out enterino- rock. One made by Mr. Todd, one-half mile northwest of the village, and another b}* Mr. Farris in section 11, each have a depth of 100 feet and are mainly through blue till. A well near Farmington, made by Mr. T. Allison, reached a depth of 132 feet without entering rock, mainly through blue till. East from this well, in the Embarras Valley, rock is exposed up to a level within 75 feet of that of the well mouth. At Diona, on the plain outside the Wisconsin drift sheet, wells are (jbtained at a depth of only 12 feet, and are mainly through gravel. CUMBERLAND COUNTY. GENERAL STATEMENT. Cumberland County is situated south of Coles, in the east-central part of the State, with Toledo as the county seat, and it has an area of 350 square miles. The Embarras River leads southward through the east- central part of the county and drains its eastern half. The western part is tributary to the Little Wabash River, which leads southward near the county line. This dounty is strikingly in contrast with Coles County on account of the absence of the Wisconsin di-ift sheet, which covers only a few square miles on its north border. Its surface is covered with the deposit of white clay which is so prevalent in southern Illinois outside the limits of the Wis- consin drift. This clay absorbs water so slowly on the interflu-sdal tracts of Cumberland County that most of the water not removed by the sti'eams is evaporated. The surface is very level, and this feature works to the disad- vantage of the development of drainage systems. There is, however, a much more mature system of drainage here than on the Wisconsin drift sheet in Coles County, a feature wliich points strongly to the comparative freshness of the latter sheet and recency of its deposition. The thickness of the drift is known at but a few points, and these are in the vicinity of the Embarras River. In places the rock occurs along this river at a level only 30 or 40 feet below the level of the uplands, but in other places Avells near the river show that the drift extends fully 50 feet below the bed of the stream, or over 100 feet below the level of the uplands. Beneath the white clay, which is usuall\' l>ut 4 or 6 feet in thickness, there is WELLS OF CUMBEELAND COUNTY, ILLINOIS. 737 a black soil formed at tlie surface of the till. The body of the di-ift appears to be generally a hard till oxidized to a yellowish color for a depth of about 12 to 15 feet, beneath which it has a blue-gray color. The wells in this county, like those in Clark County, on the east, are usually of sufficient capacity to siipply the needs of the residents, though they seldom yield more than 10 barrels a day. The till apparently has only local inclusions of sand and gravel, seldom of suiiicient amount to furnish strong wells. The depth of wells rarely exceeds 40 feet, and the majority are only 10 or 15 feet. It is probable that they are largely filled from the well mouth by water running into them from the surface of the ground during- rainy seasons. INDIVIDUAL WELLS. At Toledo the strongest wells are obtained at about 60 feet from gravel below till. At the bend of the Embarras River, about 5 miles northeast of this village, two wells situated on the terrace about 20 feet above the river are 67 and 71 feet in depth. They each penetrate about 20 feet of gravel, beneath which they are entirely in sand and do not strike rock. At the bluff of the river, east of these wells, the following section is exposed, which, it will be observed, is entirely different from the sections of the wells : Section of bluffs of Embarras River, near Toledo, Illinois. Feet. White clay 4 Soil and pale clayey snbsoil 5 Brown till 10 Gray till 30 At Greenup the wells are usually obtained near the base of the drift, at a depth of about 30 feet. The rock in the vicinity of Grreenup stands at an elevation nearly 50 feet above the Embarras River. At Neoga, on the west border of the county, wells are usually obtained at about 15 feet. A boring for coal is reported to have entered rock at less than 40 feet, there being- a bed of coal at that depth. SHELBY COUNTY. GENERAL STATEMENT. Shelby County is situated southeast of the center of the State, imme- diately west of Cumberland and Coles counties. It has an area of 776 MON XXXVIII 47 738 THE ILLINOIS GLACIAL LOBE. square miles, witli Shelbyville as the county seat. The Kaskaskia River traverses the county in a north-and-south direction and drains nearh" all its surface. A small area in the southeast part is tributary to the Little Wa'.jash, and the northwest corner of the county is tributary to the Sang-anion River. The Shelbyville moraine passes across the northeast part of the county making an abrupt turn at the city of Shelbyville from a westward to a northward course. The portion of the cormty outside the Shelb}'ville moraine is generally plane, but the west part of the county is dotted with knolls of drift, some of which reach a height of over 100 feet and many are at least 50 feet. In the portion of the county occupied by the Wisconsin drift there is a sheet of soft blue till 50 to 100 feet or more in depth, covering the harder till, which extends into the outlying districts. Exj^osures of the hard till beneath the Wisconsin drift are to be seen along the Kaskaskia River in the Adcinity of Shelbyville. There are also along the stream near Shelbyville exposm-es of the white clay which covers the hard till. The drift outside the Wisconsin sheet consists usually of till ; but some of the knolls and ridges contain a large amount of gravel or sand. Rock is often entered in tliis district at a depth of 50 feet or less, except on the drift knolls and ridges, where the distance to rock is usually increased by the measure of the height of the knoll or ridge. The wells are usually obtained without entering rock. Those on the Wisconsin drift are frequently sunk to depths of 75 or 100 feet, but those on the older sheet outside the limits of the Wisconsin drift seldom exceed 30 feet. INDIVIDUAL WELLS. At Moweaqua, on the plain outside the Wisconsin drift, in the north- west part of the county a coal shaft penetrates 65 feet of diift. The u})per 22 feet is a comparatively soft clay, but the remainder is a ver}- hard blue till. A well in jirocess of excavation at the time the writer was there exposed the following section: Section <>/' ircll at Moweaqua, lUiiwifi. • Feet. Lochs or pebbleleas yellow silt 8 Yellow cliiy witli a few fine pebbles 7 Deeply oxidizeil till, very i)obbly 9 Hani blue till at bottom. WELLS OF SHELBY COUNTY, ILLINOIS. 739 The Mauual of American Waterworks, 1897, reports that the public water supply at Moweaqua is obtained from wells, but the depth is not given. iVt Tower Hill a coal boring- enters rock at 60 feet. Drift knolls in 'to this \dllage rise about 60 or 75 feet above the level of the ground at the point where this boring- was made. The wells in the vicinit}' of Tower Hill are usually obtained at 20 feet or less, from beds of sandy clay over- lying a hard blue till. The public water supply at Shelbyville is pumped from the Kaskaskia River. Wells are usually obtained at depths of 30 to 50 feet from sand below till; in some cases they are obtained at the base of the Wisconsin drift. At Cowden, near the south border of the county, wells are usually obtained at about 20 feet, just above the hard blue till. Rock is struck at 40 or 50 feet An exposure on the Kaskaskia bluffs, near Cowden, has the following section: Section of bluffs of Kashashia River ^ near Cowden, Illinois. Feet. White clay 5 Yellow clay with a few pebbles 3 Reddish-brown sandy till 6-8 Yellow till, blue in places 10-15 Hard blue till 20 Coal Measures shale at base of blutf. Total drift 45 At Stewardson, in the southeast part of the county, wells are usually obtained at 20 to 40 feet without entering- rock, and similar conditions occur at Strasburg. At the village of Windsor, which is located on the Shelbyville moraine, the village well penetrates 90 feet of soft till, apparently belonging to the Wisconsin drift, beneath which there is a harder till with sandy matrix. Water was obtained in sand at a depth of 127 feet. Several prospect bor- ings have been made by Mr. Jerry Linn^dlle at this village, which have reached depths ranging from 120 to 170 feet without entering rock. Gas was found in sand at 115 to 120 feet, and beneath this at about 135 feet a black muck was penetrated. Whether this muck was formed in a valley bottom in a stage just before the Wisconsin drift was deposited or is sepa- rated from the Wisconsin by a glacial deposit of greater age is not made 740 THE ILLINOIS (ILAOIAL LOBE. clear by the records of these borings. There appears, however, to be a deposit of sand extending from the base of the Wisconsin till sheet down to the bed of muck. At the village of Findlay, in the north part of this county, several gas wells have been obtained at shallow depths, ranging from 45 feet to about 150 feet. One well only 45 feet in depth has furnished gas for a period of five years in sufficient amount to supply three stoves. Some of tlie wells pass through a thin bed of rock before obtaining gas, while others obtain it in the drift. The pressure is estimated to be about 12 pounds per square inch in the wells now in use, though in some cases a stronger pressure may be found since some have not been tested with a gauge. MONTGOMERY COUNTY. GENERAL STATEMENT. Montgomery County is situated in the south-central part of the State, with Hillsboro as the county seat, and has an area of 702 square miles. The drainage is mainly southward through the several headwater forks of Shoal Creek, a tributary of the Kaskaskia River. The extreme noi-th border of the county is tributary to the Sangamon River. There are narrow strips with flat, rather imperfectly drained surface on the divide between Shoal Creek and streams flowing north or west; but the greater part of the county has good drainage. The belts of knolls and ridges noted in southwestern Shelby County cross the eastern and central portions of Montgomery County, and also occur at a few places in the southern part of the county. The best defined belt is in the northeastern part, immediately east of Witt, Nokomis, and Ohlman. A ridge there rises to a height of nearly 100 feet above the bordering plains, and is maintained continuously for several miles. On the plane portions of the county a hard blue till is usually entered at 15 or 20 feet, after penetrating beds of loess and yellow till. Many of the wells are obtained above this blue till. On the knolls and ridges the distance to the l)lue till is apparently greater than on the plains. A few wells have entered it at about 40 feet, after penetrating a series of day, sand, and gravel beds of brown or yellow color. In a few places on the plain the drift has been found to have a thickness of more than 100 feet. On the prominent knolls and ridges it probably exceeds that amount. WELLS OP MONTGOMERY COUNTY, ILLINOIS. ' 741 Rock is often entered at 50 to 75 feet, and is exposed along- the streams at a similar level below the upland plain. Occasionally the thickness of the drift is but 10 or 20 feet, as at Harvel and Witt, noted below. INDIVIDUAL AA^ELLS. At Thomasville, in the extreme north part of the county, the wells enter rock at a depth of about 30 feet, but are usually obtained near the base' of the drift. At Harvel rock is entered at 14 to 20 feet. At Nokomis, in the eastern part of the county, the drift is about 100 feet in depth. The Manual of American Waterworks reports that the public water supply is obtained from di-iven wells, but the depth is not given. In the vicinity of Witt, a few miles south of Nokomis, rock is entered at about 10 feet, but wells are obtained without difficulty near the top of the rock. At Hillsboro the public water supply is obtained from springs. Wells are usually obtained at depths of 18 to 25 feet just above the blue till. They occasionally reach a depth of 60 feet. A coal boring made near this city shows a complex series of di'ift beds, as follows: Section of coal horing near Millshoi-o, Illinois. Feet. Pale silt and pebbly browu clay 14 Bluish-gray till ..- 23 Sand 1 Blue-graj' till 16 Yellow clay 7 Sand and gra vf 1 20 Blue till _ 26 Sand and gravel 16 Total drift ^is In the vicinit}" of Butler rock is struck at about 50 feet and the drift is mainly till. Wells are usually obtained at 20 feet or less. . The city of Litchfield obtains its public water supply from Shoal Creek. A coal boring at tins city penetrated 75 feet of drift. Wells are usually obtained at 25 to 40 feet. About 1^ miles southeast of Litchfield several deep wells have been drilled for oil, a small quantity of oil being- obtained at about 675 feet. The drift at these wells is 52 to 60 feet, and mainly a hard blue till. . On the plane tracts in the southeastern part of the county wells are usually obtained at about 15 feet just above the blue till. On neighboring 742 THE ILLINOIS GLACIAL LOBE. knolls they are often sunk to depths of 40 feet or more without encoimter- ing blue till. A well on a drift ridge in the east part of the county in sec. 17, T. 10, R. 1 W., reached a depth of 97 feet without entering rock and was mainly through a hard clay of yellowish brown color. Beds of dry sand and cob- blestone were also penetrated. A well on a neighboring section (sec. 20) obtained water in cobble below brown till at a depth of 40 to 47 feet. MACOUPIN COUNTY. GENERAL STATEMENT. Macoupin County is situated southwest of the center of the State, imniediately south of Sangamon and west of Montgomery County. It has an area of 864 square miles, with Carlinville as the county seat. The county is traversed nearly centi'ally from east to west by Macoupin Creek, which is the only stream of importance found within its limits. The south- east part is drained southward through Silver, Cahokia, and Piasa creeks and Wood River. The northwest portion of the county drains westward through Apjjle Creek. Narrow strips of imperfectly drained land occur along the divide between Macoupin Creek and streams flowing southward, but the greater portion of the county is well drained. It has a thin deposit of silt somewhat less porous than typical loess, yet it absorbs the excess of rainfall more rapidly than the white clay districts to the east. The drift sxirface is generally plane, though occasional knolls 20 to 30 or even 50 feet in height occur. The largest ones noted are about 5 miles easi of Carlinville, on the borders of Macoupin Creek. The thickness of the drift is apparently less on the water partings in the north and south parts of the county than near Macoupin Creek in the central portion. It is probable as noted above that this stream follows approximately tlie line of a preglacial A'alle}'. '^i'he wells are usually found at depths of 2.5 to 50 feet, many of them obtaining their supply above blue till, but others in sand and gravel beneath it. 'I"'he wells and natm-al exposures indicate that a sheet of hard blue till is generally ])resent in this county as in Montgomery County, setting in at about 20 feet and extending to the rock. WELLS OF MACOUPIN COUNTY, ILLINOIS. 743 INDIVIDUAL WELLS. At Virdeii, in the iKirth part of the county, wells are usually obtained at 15 to 25 feet from sandstone, the drift being very thin in the vicinity of that village. The best wells are estimated to yield 50 barrels per day, but usually a well will afford only a small fraction of that amount. During the di'ought of 1894-95 so many of the wells became dry that fears of a water famine arose. At Modesto, also near the north border of the county, rock is entered at 25 or 30 feet, but wells are usually obtained near the base of the drift. In the vicinity of Scottville, in the northwest part of the county, the' drift is about 50 feet in depth and usually affords abundance of water for wells. At Girard and Nilwood, in the northeastern part of the county, the coal shafts enter rock at about 70 feet. Wells are usually obtained from thin beds of sand at about 20 feet. The drift is mainly a blue till. At Carlinville the public water supply is pumped from Macoupin Creek. A coal shaft enters rock at about 75 feet. In the Geology of Illinois an instance of the penetration of a thick sheet of drift near this city is noted. A boring- in Macoupin Creek Valley, made by T. L. Loomis, reached a depth of 160 feet without entering rock. It was mainlv through blue till. At Medora a coal boring- is reported in the Geology of Illinois to have the following section: Feet. Yellow till 24 Bine till 30 Gravel 20 Total drift 74 In the vicinity of Brighton, in the southwest part of the county, rock is struck at about 30 feet, but wells are usuall}^ found in the drift. At Bunker Hill wells are usually obtained at 20 to 30 feet in sand below till. They are estimated to have an average daily yield of about 5 ban-els. A coal shaft in this village is reported in the Geology of Illinois to enter rock at 28 feet. At Staunton the public water supply is obtained by impounding water 744 THE ILLINOIS GLACIAL LOBE. Oil tributaries of Cahokia Creek. Private wells are obtained usually at 16 to 20 feet. Coal shafts penetrate 90 to 110 feet of drift, mainly blue till. The drift is much thinner northwest from Staunton than at this village, rock Ijeing exposed along Cahokia Creek at a level only 25 feet below the bordering uplands. At the villages of Gillespie and Dorchester rock is entered at 25 to 40 feet, or at a higher elevation than the surface of the ground in Staunton, the altitude of the railway station at Gillespie being 60 feet and at Dorchester 45 feet above Staunton. GREENE COUNTY. GENERAL STATEMENT. Greene County is situated on the east side of the Illinois River, a short distance above its mouth, and has an area of 544 square miles, with Carroll- ton as the county seat. It is drained westward principalh' by Apple Creek and Macoupin Creek, the former leading throug'h the north-central and the latter through the southern portion of the county. Each of these streams flows in a trough-like depression, which probably was the line of a pre- glacial stream. The divides on either side of these depressions rise 50 or 75 feet above the level of the drift surface on the borders of the creeks, and they apparently have a thinner coating of drift than the trough- like depres- sions. Wells, however, are seldom sufficiently deep to test the thickness of the drift. The county is well drained by streams and has also a coating of loess which absorbs the rainfall rapidly. There are a few drift knolls in the western half of the county, the largest of which rise about 50 feet above bordering plane tracts. There are not such well-defined ridges in this county as in Pike and Adams coun- ties, but it is thought that these knolls in Greene County mark the continu- ation of the belt of drift ridges noted in those counties. The drift of Greene County consists largely of blue till, as in counties to the north and east. The feAv borings which haxe reached rock penetrate about 50 feet of drift, and this is probably about the average for the county. Preglacial valleys may ])erhaps materinlly increase the average. The wells are usually obtainc^l before entering blue till at a de])th of l)ut 15 or 20 feet. In the Illinois bottoms they are often sunk to a dejith of 40 feet, mainly tlirough fine sand. WELLS OP GREENE COUNTY, ILLINOIS. 745 INDIVIDUAL AVBLLS. At Roodhouse, in the north part of the county, at an altitude about 650 feet above tide, wells obtain water at 15 to 25 feet in a gravel below clay. A coal boring is reported in the Greology of Illinois to have penetrated 75 feet of drift, but one near the mill entered rock at 35 feet after penetrating the following beds : Section of drift in a well at the Roodhouse mill. Feet. Loess : 10 Yellow till 15 Blue till 10 Total 35 At Whitehall, 4 miles south of Roodhouse and at 75 feet lower eleva- tion, the drift is shown by several wells to have a thickness of about 50 feet. In parts of the village strong wells are obtained at 20 feet, but in other parts they are sunk to the rock. At Carrollton the public water supply is from a well 1,330 feet in depth, which terminates in the St. Peter sandstone. It has a head 50 feet below the surface, or 565 feet above tide. A peculiar series of beds were penetrated before the rock was entered, there being a black muck about 32 feet in depth immediately below the loess, and under this beds of yellow and red clay extending to the rock, no typical till being found. Rock was entered at about 60 feet. At Greenfield the wells are 18 to 30 feet in depth and obtain their supply from gravel or from clay. The usual depth is about 20 feet. CALHOUN COUNTY. GENERAL STATEMENT. Calhoun County occupies the narrow strip of land between the Illinois and Mississippi rivers just above their junction. It has an area of 260 square miles, and Hardin is the county seat. The elevation is in places 350 feet above the neighboring streams, and as the neck of land between the streams is scarcely 6 miles in average width, the topography is very rugged com- pared with the general topography of Illinois. Glacial drift is found only in a small portion of the county, and it is thought by Professor Salisbury, 746 THE ILLINOIS GLACIAL LOBE. who has examined the couuty in sdme detail, that the greater part of it has never been glaciated.' The upland portion of this county is sparsely settled, and in conse- quence iew wells have been made. Cistern water furnishes those who have not the money to sink deep wells. In the Illinois and Mississippi bottoms there are rich farms, and the wells obtain water at depths of 30 to 60 feet in the sand of the river bottoms. JERSEY COUNTY. GENERAL STATEMENT. Jersey County is situated on the east side of the Illinois River, extend- mg to the mouth of tha,t stream and a few miles down the Mississippi. It has an area of 360 square miles, with Jerseyville as the county seat. The northern part of the county is tributarj^ to Macoupin Creek. The central portion drains westward through Otter Creek to the Illinois River. The southeastern portion drains southward through Piasa Creek to the Missis- sippi River. These streams afford good drainage. There is also a coating of loess which absorbs the rainfall rapidl}^ Along the southern border of the county an elevated ridge formed by an upheaval of the rock strata rises in places to an altitude of 400 feet above the Illinois and Mississippi rivers, that flow along its base, and nearly 200 feet above the portion of the county to the north. Aside from this ridge the features of Jersey County are quite similar to those of Greene County. The northern portion slopes to the trough-like depres- sion occupied by Macoupin Creek. A low ridge having rock at sHght depth leads westward past Jerseyville, separating the drainage basin of Macoupin Creek from the basins of Otter and Piasa creeks. A few drift knolls and ridges occur in the western and southern parts of the county, the highest of which rise perhaps 75 feet above bordering- jjlains, and whicli are a continuation of the belt in western Greene County, noted above. The belt of knolls is traceable nearly to the Mississippi bluffs south of Newberii, in the southern ]);irt of the ccnmty. 'i'lic drift, as in counties to the north and east, consists mainly of till. Itsthi{;kness riuiges tVoin 20 feet or less up to fully 100 feet. Records of eight borings which reach rock show an average of 30 feet, but preglacial ' I'roc. Am. Assoc. Adv. Sri., W:i«liiiiKtoM iiici'l ins. ISill. pp. L'.">l-2riS. WELLS OF JERSEY COUNTY, ILLINOIS. 747 valleys are liable to increase the average much beyond this amonnt. The drift is sufficient to greatly obscure the preglacial valleys and ridges. Wells are ordinarily but 20 or 30 feet in depth, being obtained usually before entering the blue till. On the bottoms of the Illinois and Mississippi they are obtained at about 30 feet in sand and gravel. INDIVIDUAL WELLS. At Fieldon, in the western part of the countv, rock is strack in wells at about 25 or 30 feet, and the best wells are obtained from this source at depths of 40 to 60 feet. At Otterville the wells are from 14 to 3-5 feet in depth, and iisually obtain water without entering rock. A section on Otter Creek bluff, near this village, reported in the Geology of Illinois, is as follows: Section of blifff' of Otter GreeJc, near Otterville, Illinoifs. Feet. Yellowish broivn clay (mainly loess) 16 Sand and gravel with bowlders 30 Blue clay 15 Total 61 The writer found a similar section on a ravine southwest from Fieldon, and there the blue clay at the base is a typical till. At Beatty's Mound, between Otterville and Jerseyville, a well reached a depth of 65 feet without entering rock. The mound or drift krioll stands about 40 feet above the bordering plain. Wells on the plain north of the mound enter rock at about 30 feet. At Jerse}^'ille the public water supply is obtained from a well 2,003 feet in depth, which obtains most of its supply from the St. Peter sand- stone at 1,400 to 1,600 feet. The water rises within 100 feet of the sur- face, or to 562 feet above tide, and the well will ^nield by pumping 200 gallons per minute from a 3-inch hole. An analvsis of the water is pre- sented in the Seventeenth Annual Report of this Survey (Part II, p. 827). It contains about 86 grains of salt per gallon, but is considered a palatable water. Rock is entered in that vicinity at about 20 feet, and wells are obtained either near the base of the drift or the top of the rock. At Fidelity, in the eastern part of the county, wells are usually obtained at about 25 feet near the base of the drift, but a few pass into the underlying rock. In the eastern and southeastern parts of the county the drift is 20 to 35 feet in depth, and wells not infrequently enter the rock. 748 THE ILLINOIS GLACIAL LOBE. MADISON COUNTY. GENERAL STATEMENT. Madison County borders the portion of the Mississippi River between Alton and East St. Louis and extends a short distance northwest of the former city. It has an area of 740 square miles, with Edwardsyille as the county seat. The eastern part of the county drains southward thi'ough Silver Creek, a tributary of the Kaskaskia. The northwestei'n portion is drained southwestward to the Mississippi through Cahokia Creek and Wood River. The drainage is generally sufficiently well developed to carry off the surplus rainfall rapidly, but there are small tracts in the eastern part of the county where di'ainage lines are not well developed, and the white clay which covers that region will not absorb the rainfall. The western half of the county is covered with a liorous loess which absorbs water rapidly. The southeastern part of the county is traversed in a southwestward course by a belt of drift ridges and knolls, which rise in places to a height of 50 or 75 feet above the bordering plain. A few knolls occur in the northeastern part of the county, Avhich reach heights of 30 to 50 feet. In the western part of the county the surface is generally plane, though a knoll about 4 miles northwest of Edwardsville has a height of 30 or 40 feet, and knolls 10 to 15 feet in height are not rare. The drift of this county, like that of Macoupin County, which joins it on the north, consists largely of a compact till. This till has been noted along the bluffs of the Mississippi as well as farther east, and the entire county appears to have been heavily glaciated. Stria; have been found in several places in and north of Alton, within 1 or 2 miles of the Mississippi River. The average thickness of drift in fifteen borings which reach the rock is found to be 40 feet. As this does not include borings which have been made in ])reglacial valleys, the average for the county probably is somewhat greater than 40 feet. Wells are often obtained at depths of 20 to 25 feet without entering a blue till, and they very seldom need to be carried into tlie rock. Wells furnishing 20 barrels per day ma)' usually be obtained from the drift, both at shallow and greater depths. Wells are often sunk below the first water vein in order to guard against contamination, for the porous loess of the WELLS OF MADISON COUNTY, ILLINOIS. 749 western part of the county offers a medium for ready transmission of impurities. INDIVIDUAL WELLS. At Godfrey, in the northwest part of the county, a deep well has recently been sunk to the St. Peter sandstone and this supjjlies the Monti- cello Seminary. Wells at the railway station reach a depth of about 30 feet without entering- rock. At Alton the public water supply is pumped from the Mississippi River. Wells on the uplands in the north part of the city penetrate 30 to 40 feet of drift, and frequently obtain water without entering the rock. At Upper Alton the wells on the upland are usually obtained at 30 to 40 feet, near the base of the drift. The loess in this village has a thickness of 20 feet or more, but is underlain by typical till, exposures of which may be seen near Wyman Institute. The village contemplates putting- in watei'- works, which will be supplied from, wells in the Mississippi Valley. In the vicinity of Fosterburg, in the northern part of the county, wells are obtained at about 25 feet. The loess in that locality is only about 8 feet in depth. At Edwardsville the wells range in depth from 20 to 80 feet, the shallower ones being obtained just below the loess, while the deeper ones pass tlrrough a large amount of till and enter rock near the bottom. This city is also contemplating waterworks, but the source of supply has not been ascertained. At Collinsville the public water supply is from two wells 575 and 600 feet in depth. The wells are located on the Mississippi River bluff, 100 feet above the railway station, and water will rise to a level 120 feet below the surface. The wells have a combined capacity of not more than 50,000 gallons per day. The water is slightly saline, but can be drank by most people without discomfort. The supply is probably either from the Coal Measures or Lower Carboniferous sandstone. The drift and loess at these wells is about 90 feet in depth, but probably not less than 40 feet is loess. Attention is here called to an error in the altitude of the well mouth given in the writer's paper in the Seventeenth Annual Report (p. 811), the altitude being 565 feet instead of 465 feet as there given. 750 THE ILLINOIS GLACIAL LOBE. In the viciuity of Troy wells are obtained at about 30 feet. The loess at this villag-e is 12 or 15 feet in depth. In the vicinity of St. Jacobs wells occasionally enter rock at depths of 40 or 50 feet if on low ground between the drift ridges. The drift is prob- ably much thicker on the drift ridges, though no records of deep wells were obtained. At Highland the wells on low ground among the drift ridges enter rock at 25 to 50 feet, but many are obtained without reaching the rock. North and east of Highland wells usually obtain water at about 20 feet without' entering rock. At Grrant Fork rock occurs at a level only 20 feet below the upland plain, and several wells west of this village have been drilled into the rock a few feet. No data were obtained concerning the depth of wells in the northeast fourth of the county. BOND COUNTY. GENERAL STATEMENT. Bond County is situated east of Madison, in the south-central part of the State, and has an area of 380 square miles, with Greenville as its county seat. The greater part of the county is di-ained southward through Shoal Creek, a tributary to Kaskaskia River. The Kaskaskia touches the south- east corner of the county. The streams aftbrd rather imperfect di-ainage, and the white clay which covers the glacial drift is a slow absorbent of rain- fall. The excess of rainfall is therefore largely disposed of by evaporation except on the immediate border of di-ainage lines. A system of drift ridges leads across the county from northeast to southwest. There are also scattering knolls over all of the county. These knolls and ridges rise in some cases 50 or even 75 feet above the bordering plains, The thickness of the drift is known at but few points. Six borings which have reached rock show an average thickness of 85 feet, which is probably not far from the average for the county. The upper 20 feet con- sist of yellow or ash-colored clays, which in places assume a sand}' structure and supply water for the majority of wells. The deeper portion of the drift consists usually of l)lue till, but a boring at Greenville shows a large amount of sand and gravel. WELLS OF BOND COUNTY, ILLINOIS. 751 INDIVIDUAL WELLS. Wells ill the viciuitA' of Soreuto, in the northwest part of the county, often reach a depth of 30 feet and penetrate the following beds: Generalized section of wells in northwestern Bond County, Illinois. I'eet. White clay 5 Yellow till 12-15 Blue till 10-15 Near Old Ripley the drift is about 50 feet iu depth, but only a few wells reach the rock. Its structure is like that at Sorento. At Greenville wells are usually obtained at 35 feet in sand and gravel below clay. The public water supply is from a well 22 by 35 feet, in the bottom of which several tubular wells have been sunk to depths of 10 or 20 feet. There are also two 6-inch wells sunk near the large well, which reach a depth of 45 feet. A coal boring at Greenville, reported in' the Geology of Illinois, penetrated 204 feet of drift, as follows: Section of coal boring at Greenville, Illinois. Peet. Soil anil clay 10 Sand anil clay 20 Coarse sand 10 Gravel - 20 Cemented gravel (possibly till) 90 Clay and saud 20 Sand 8 Light clay and sand - 8 Dark clay and sand 18 Total drift 204 A well in the valley of Shoal Creek, 3 miles above Greenville, is reported to have reached rock at 87 feet and to have been sunk entirely through blue clay. Wells on a drift ridge in the city of Greenville in some cases reach a depth of 80 or 90 feet, in which the upper 20 feet is largely clay and the remainder sand and gravel. At Smithboro a coal boring reported in the Geology of Illinois pene- trated 95 feet of drift, as follows : Section of coal boring at Smithboro, Illinois. Peet. Soi 1 and clay 15 Hardpan (probably till) 60 Bine clay 10 Hardpan 10 Total drift 95 752 THE ILLINOIS GLACIAL LOBE. lu the ^^cinity of Wobuni wells on low drift ridges reach a depth of 40 feet and are largelv through gravel. On the plain east of Woburn wells are usually obtained at about 25 feet and are mainly tlu-ough till. In the east part of the county, near Pleasant Mound, wells are usually obtained at 25 or 30 feet withou.t entering rock. A well on a knoll 1^ miles southeast from Pleasant Mound entered rock at 48 feet, which is about the level of the base of the knoll. FAYETTE COUNTY. GENERAL STATEMENT. Fayette County is sitiiated in the south-central part of the State, and has an area of 720 square miles. Vandalia is the county seat. The Kas- kaskia River leads nearly centrally from northeast to southwest through the county and has broad bottoms averaging probably 3 or 4 miles in width. No large tributaries enter within the limits of this county. Like Bond Count)' a portion of Fayette has imperfect drainage, due in part to the poor development of drainage lines and in part to the compact wliite clay which caps the sui-face. A system of prominent drift ridges is found in the southwestern part of the county. The most prominent belt leads from Vera past Vandalia to Pleasant Mound in Bond County. It stands in some places 100 feet above the bordering plains and presents a complex series of ridges and knolls with an average breadth of 2 miles. The remainder of the county has a neai'ly plane surface. No records of wells have been obtained by the writer in this county except at Vandalia, and the thickness of the drift is known at but few places, where outcrops of rock occur. There is apparently a filling of about 100 feet along the Kaskaskia River and its preglacial tributaries, but on the uplands the thickness is only 20 to 40 feet. INDIVIDUAL WELLS. Wells on the drift ridges in the vicinity of Vandalia frequently reach a depth of 75 feet and are mainly through a gravelly drift. The Manual of American Waterworks (1897) reports that a waterworks system is about to be constructed which will obtain its supply from the Kaskaskia River. WELLS OP EFFINGHAM COUNTY, ILLINOIS. 753 A boring for coal made at this city reached a depth of 574 feet. It entered rock at about 95 feet, after penetrating a complex series of drift beds. From the report in the Geology of Illinois (Vol. VI) the following' information concerning- wells is obtained. In the north part of the county the wells are 12 to 18 feet, with weak veins of water. A well near Ramsey was dug 100 feet through clay and gravel to solid rock. Wells about a mile south of Vandalia are reported to reach a depth of 60 or 65 feet on the drift ridges and about 30 feet on the bordering plane tracts. The wells usually pass through a small amount of clay at the top, beneath which they are largely through sand. EFFINGHAM COUNTY. GENERAL STATEMENT. Effingham County is situated in the south-central part of the State, immediately east of Fayette County, with Effingham as the county seat, and has an area of 490 square miles. The greater part of the county is tribixtary to Little Wabash River, which has a southward course through its central portion. From the western border of the county the drainage is westward to the Kaskaskia. The divides in this county are poorly drained as in neighboring counties, and there is a coating of white clay over the entire upland surface which absorbs water very slowly. The drift surface is generally plane, there being no prominent ndges or knolls, such as occur in the neighboring counties on the north and west. Rock is exposed along the Little Wabash and its tributaries and also along tributaries of the Kaskaskia at levels only 20 to 40 feet below the border- ing uplands. The tliickest section of drift obtained within the county is only 60 feet. The upper part of the drift to a depth of 25 feet or more is composed of clays of yellow or brown color which usually afford water for the wells. Under these clays is a hard blue till extending frequently to the rock. INDIVIDUAL WELLS. At Altamont a well at the Boyer House penetrated about 15 feet of white and yellow clays with few pebbles, beneath which a hard brown till was entered, and below that, at a depth of a few feet, a blue till. The well terminated in this blue till at a depth of 47 feet. Other wells in the village obtain water without entering the blue till. Within a few miles southwest MON xxxviii 48 754 THE ILLINOIS GLACIAL LOBE. of Altamont, on the divide between the Little Wabash and Kaskaskia, wells enter rock at about 30 feet and obtain water at 40 or 50 feet. In the vicinity of Moccasin and Beecher wells occasionally enter rock at 30 to 40 feet, but are usually obtained at 20 or 30 feet from drift beds of sandy structure. In the vicinity of Effingham wells are obtained at 18 to 20 feet in sandy beds below till. Rock is entered at 25 or 30 feet. The supply for waterworks is pumped from Little Wabash River. In the vicinity of Edgewood and Mason, in the southern part of the county, rock is usually entered at 20 to 25 feet, but most of the wells obtain their supply from near the base of the drift. A coal boring near Edge- wood is reported, in the Geology of Illinois, to have penetrated 59 feet of drift. JASPER COUNTY. GENERAL STATEMENT. Jasper County is situated east of Effingham, with Newton as the countv seat, and has an area of 506 square miles. The Embarras River runs south- eastward through the central portion of the county. Its tributaries are mainly on the northeast, leaving the western and southern portions of the county outside its drainage basin and tributary to the Little Wabash. TJie valley of the Embarras is neai-ly 2 miles in average width and has sandy bottoms. The uplands in this county, as in tlie neighboring counties on the north and west, are covei'ed with a white clay, which absorbs rainfall very slowly. The drift, like that of Effingham County, is composed mainly of till of moderate depth, seldom more than 50 feet. Along the Embarras River, however, the depth is greater and may exceed 100 feet. Tributaries of the preglacial Embarras have been filled so completely that their courses can scarcely be traced. The wells are usually obtained at depths of only 20 or 30 feet. But few records have been procured, the conditions for wells being somewhat uniform throughout the county. INDIVIDUAL WELLS. In the vicinity of Newton wells are usually about 20 feet deep, and in a few instances they reach rock at that depth. The waterworks suppl}' is ])nini)(ul from the Embarras River. WELLS OF CRAWFORD COUNTY, ILLINOIS. 7o5 At St. Marie a well at Mr. Picquet's did uot enter rock at a depth of 30 feet, but other wells iu the village strike rock at only 16 feet. West from St. Marie, along the divide between Embarras and Little Wabash rivers, wells are about 20 feet in depth and do not enter rock. Wells along the Embarras River in the southeast part of the county are 30 to 45 feet in depth without entering rock. After penetrating a few feet of sand they are lai-gely tlu-ough blue till. CRAWFORD COUNTY. GENERAL STATEMENT. Crawford County is situated on the eastern border of the State imme- diately south of Clark County and east of Jasper. It has an area of 462 square miles, with Robinson as the county seat. The eastern border is fol- lowed by the Wabash River, which receives the di-ainage of a narrow strip along its west bluff. The western half of the county is tributary to the Embarras River, but that stream touches only the extreme southwest corner of the county. This county, like those on the north and west, is covered with white clay which absorbs rainfall slowly, although not so impervious to water as the white clay in the south-central part of the State. The drift is apparently of slight depth on the uplands, rock being entered in wells at many points within 10 or 15 feet of the surface. There may, however, be deeply filled preglacial valleys tributary to the Wabash and Emban-as, whose courses are concealed by the drift. Where wells do not enter rock they usually obtain water at a depth of 20 feet or less, and thus do not test the tliickness of the drift in its deeper portions. Wells which enter rock obtain water without penetrating to great depth, there being few wells more than 100 feet in depth. INDIVIDUAL WELLS. In the northern part of the county wells are usually obtained in sind- stone at a depth of 35 feet or less. The drift is often not more than 15 feet in depth. In the vicinity of Trimble the rock is in places scarcely 10 feet below the surface and wells are obtained at moderate depths in sandstone. At Robinson wells are 20 to 25 feet in depth and usually enter sand- stone a few feet. The mayor, Mr. Aldridge Walters, estimates that good wells will yield 40 or 50 barrels per day. 756 THE ILLINOIS GLACIAL LOBE. In the vicinity of Duncanville wells are obtained in sand below clay at a depth of 18 (ir 20 feet. On the higher parts of the upland rock is entered at 10 or 15 feet. In the vicinity of Flat Rock, also, the drift is but 10 or 15 feet in depth. In the west part of the county, in the vicinity of Oblong, wells art- usually obtained at about 16 feet without entering rock. LAWRENCE COUNTY. GENERAL STATEMENT. Lawrence County is situated south of Crawford, on the east border of the State, and has an area of 360 square miles, with Lawrenceville as the county seat. The Wabash River forms the eastern border of the county and Embarras River traverses it nearly ceiiti'ally. Both streams have broad sandy bottoms several miles in width. The lowlands connected with these bottoms are poorly drained, but uplands are hilly and well drained. The liigher portions of the county have a capping of white clay, but the lowlands and river bottoms are usually covered with sand. The drift on the uplands is very thin, rock usually being found within 10 or 15 feet of the surface. Wells are, however, obtained at moderate depths, there being few which have failed to obtain water within 50 feet of the surface. On the lowlands the drift is probably thick, though wells are obtained without reaching the underlying rock. A well across the Wabash, at Vincennes, Indiana, reached a level about 60 feet below the river before entering rock. INDIVIDUAL WELLS. At Lawrenceville the best wells are obtained from sandstone at a depth of about 60 feet. Rock is entered at only 10 to 15 feet. In the vicinity of Sumner strong wells are obtained at about 20 feet from sand and gravel below clay. At St. Francisville the wells average only 15 feet in depth, mainly througli sand. RICHLAND COUNTY. GENERAL S'I'ATEMENT. Richland County is situated inunediately west of Lawrence, with Olney as the county seat, and has an area of 361 square miles. The eastern por- tion of tlic county- (lr;iins southward to IVmpas River and the western WELLS OF CLAY COUNTY, ILLINOIS. 757 tliroug-h Fox River, a tributary to the Little Wabash. This county, like those to the north and west, has a coating of white clay which is very slowly pervious to water. The excess of rainfall escapes largel)^ through evapora- tion. Along the streams and in lowlands there is usually a black mucky soil, much richer than the white clay of the uplands and more readily per- vious to water. On the uplands the drift is generally very thin, the rock often being entered at only 10 or 15 feet. On the lowlands the thickness is much greater, and wells are obtained at 20 feet or less without entering the rock. INDIVIDUAL WELLS. At the city of Olney private wells usually obtain water at a depth of 10 or 12 feet from a gi-avelly bed resting on the rock. The waterworks supply, which is chiefly for fire protection and lawns, is pumped from Fox River. A boring 2,000 feet in depth was made at this city for the purpose of obtaining an artesian well. A salt water was sti'uck which does not over- flow, and no use is made of the well. South of Olney, near Parkersburg, a well is reported to have struck wood in clay at 20 feet. In the north part of the county, near Dundas, rock is usually entered at 12 to 18 feet, though wells are sometimes of less depth. CLAY COUNTY. GENERAL STATEMENT. Clay County is situated west of Richland and south of Effingham County. It has an area of 470 square miles, with Louisville as the county seat. The county is traversed by the Little Wabash River neai'ly centrally in a northwest to southeast course. The greater portion is directly tributary to this stream, but a nari'ow strip on the western border is tributarv to Skillett Fork, a stream which enters the Little Wabash near its mouth. This county, like the neighboring counties just discussed, has a coating of wliite clay several feet in depth, wliich is very slowly pervious to water. The streams, however, are bordered by broad bottoms with looser and more fertile soil. The drift on the uplands is usually^ but 15 to 30 feet in depth. Wells are in many cases obtained in the di'ift, but a large number penetrate the imderlying rock a few feet. The drift along the streams is probably of 758 THE ILLINOIS GLACIAL LOBE. greater depth than on the uplands, but no well records have been obtained to demonstrate this greater thickness. INDIVIDUAL WELLS. In the vicinit}^ of lola, in the northwest part of the county, wells obtain water at 12 to 15 feet without entering rock. They are mainly through a yellow clay. At Louisville rock is entered at about 27 feet, but wells frequenth' obtain water in the lower part of the drift. An exposiire on the bluff of Little Wabash River in this village shows the following beds: Section of bluff of Little Wabash River near Louisville, Illinois. Feet. Brown silt with few pebbles 6 Brown sandy gravel 5 Brown leached till 4 Gray calcareous till 12 Coal Measures shale 10 Total drift 27 On the uplands west and south from Louisville rock is usually entered at 15 to 20 feet, though at elevations a few feet higher than the site of the village. At Flora rock is usually strack at 15 or 20 feet and wells are obtained at 30 to 50 feet. In the vicinity of Xenia rock is entered at about 15 feet and wells obtain Avater at slight depth in the underlying sandstone or sandy shale. MARION COUNTY. GENERAL STATEMENT. Marion County is situated west of Clay County and south of Fayette, about midway between the Wabash and Mississippi rivers. It has an area of 580 square miles, with Salem as the county seat. The divide between the Mississippi and Wabash rivers passes tlu'ough the eastern part of the county. The greater part of the count}^ drains westward through small creeks into the Kaskaskia. The eastern part drains southward through Skillett Fork, a tributar)- of Little Wabash River. The streams afford imperfect drainage, and the sheet of white clay that covers the county absorbs rainfall very slowly. The excess of rainfall is therefore disposed of by evaporation. WELLS OF MARION COUNTY, ILLINOIS. 759 Throughout much of the county rock is entered in wells and coal shafts at depths of only 20 or 30 feet, but borings at Salem, Odin, and Sandoval penetrate over 100 feet of drift, apparently striking the line of a preglacial valley. Where the drift exceeds 20 feet in depth its lower por- tion is usually a blue till, but where less than 20 feet the till is of a yellow or brown color. Wells are usually obtained at only 15 to 30 feet, and the majority do not enter rock. INDIVIDUAL WELLS. At Patoka, in the northwest part of the county, a well at the railway station is reported in the Geology of Illmois to have struck rock at a depth of 60 feet. It penetrated the following beds: Section of well at Patoka., Illinois. Feet. Soil, clay, etc 15 Hardpan 15 Blue pebbly clay vrith fragmentB of coal and wood 30 Fossiliferons limestone 2 Soft shale 30 'I'otal depth 92 The wells in that vicinity ordinarily obtain water without entering rock. At Kinmundy, in the north part of the county, rock is entered at 12 to 20 feet, and wells often penetrate it a few feet to obtain water. At Salem wells are usually obtained at about 20 feet from sandy beds in the drift. A coal boring reported in the Geology of Illinois penetrated 126 feet of drift, as follows : Section of coal boring at Salem, Illinois. Feet. Soil 2 Ferruginous crust of clay ■ 3 Yellow till 9 Yellow till and sand 10 Blue till 50 Brown clay, containing wood 30 Blue clay, sand, and wood 12 Black soil 1 Blue mud and sand - 9 Total drift 126 At Odin a coal boring penetrated 100 feet of drift, and at Sandoval 128 feet. Wells at Sandoval obtain water at 14 to 18 feet from a sandy clay. A good well is estimated to yield 35 barrels a day. 760 THE ILLINOIS GLACIAL LOBE. At Centralia wells obtain water at 14 to 30 feet from clay or gravel. The public supply is from impounded water. CLINTON COUNTY. GENERAL, STATEMENT. Clinton County is situated west of Marion County, in the southwestern part of the State, with Carlyle as the county seat, and has an area of 494 square miles. The Kaskaskia River leads southward through the eastern part of the county and there turns westward, forming the south boundary. Shoal Creek, its largest ti'ibutary, traverses the west-central part of the county and enters the Kaskaskia about 8 miles from the west border of the county. Crooked Creek, an eastern tributary, forms a part of the south boundary of the county. The streams have channels sunk but a few feet below the level of the bordering plains and drainage lines are not well developed. The compact white clay which covers the county absorbs the rainfall slowly, thus leaving much of it to be disposed of by evaporation. Occasional drift ridges and knolls break the monotony of the plain. The highest reach elevations of 50 to 75 feet or more above the plain, and the majority have a height of fully 30 feet. The best developed system of ridges appears along the Kaskaskia River, east and southeast of Carlvle. There is a nearly continuous chain of knolls about 5 miles in length, which crosses the Baltimore and Ohio Railway in north to south direction ab(iut 3 miles east of Carlyle. These knolls and ridges connect on the north with those in Bond and Fayette counties already discussed. The thickness of the di'ift in this county seldom exceeds 50 feet, and not a few wells enter rock at 15 to 30 feet. A few drift sections are reported in the Geology of Illinois which penetrate 70 feet of drift. In its thicker portions the di-ift includes a hard blue till near its base, but it usualh' has a yellow color to a depth of at least 20 feet. The wells are obtained either in the sandy portions of the yellow till or at slight depth in th6 underlying rock. The blue till is apparently very compact and a poor medium for su])plying water. INDIVIDUAL WELLS. At Carlyle wells are usually obtained at about 25 feet without entering rock. The waterworks are supplied from the Kaskaskia River. WELLS OF CLINTON COUNTY, ILLINOIS. 761 A well on one of the di-ift knolls southeast from Carlyle in sec. 14, T. 1 N., R. 2 W., was mainly through sand and gravel to a depth of 46 feet. It is thought by the residents that most of these knolls and ridges contain much sand and gravel. The following table of well borings is compiled from data furnished in the Geology of Illinois (Vol. Ill): WelLi in Clinton County. Owner or location. Altitude (above tide). Depth. Remarks. Sec. 5, T. 3, R. 2 W . . . Feet. 500 500 475 475 475 450 490 Feet. 40 36 50 70 70 52 27 Sec. 6, T. 3, R. 2 W Beaver Prairie, T. 3, R. 3 W. . . . Drift knolls, T. 1, R. 3 W Sec. 34, T. 2, R. 4 W No rock ; several wells. Several wells ; drift about 70 feet. On knoll, mainly saml. ST. CLAIR COUNTY. GENERAL STATEMENT. St. Clair County is situated in the .southwestern jjart of the State and borders the Mississippi River for a few miles opposite the city of St. Louis. It has an area of 680 square miles, with Belleville as the county seat. The Kaskaskia River crosses its southeastern corner, and the greater part of the county is tributary to that river tlii-ough Silver and Richland creeks, there being only a narrow strip along the bottoms and east bluff of the Missis- sippi which is not tributary to it. This strip along the Mississippi bluffs is largely underlain by St. Louis limestone, in which subterranean drainage is developed through caverns and sink holes. The western portion of the county is covered with a deposit of porous loess, which extends as far east as the meridian of Belleville. The eastern portion is largely covered by a white clay, though scarcely so compact as that found in counties to the east. A belt of prominent drift ridges leads southward through the eastern half of the county, passing between Lebanon and O'Fallon, and just east of the city of Belleville. These ridges rise in places to a height of fully 762 THE ILLINOIS GLACIAL LOBE. 100 feet above tlie bordering- plain, and are a foutinuation of the belt which crosses southeastern Madison County, noted above. East of this belt there are a few isolated knolls or groups of knolls which stand 30 to 50 feet or more above the border plains. In the elevated limestone district on the west border of the county there is but little glacial drift beneath the loess, but eastward from the belt of drift ridges just noted the county is coated so heavily that wells seldom reach the rock. The extreme southeast part of the county, however, has a thin coating of drift, and wells often enter the rock. The drift ridges are composed in part of till and in part of sand and gravel. A blue till is found near the base, but the upper 30 or 40 feet is usually of brown or yellow color. INDIVIDUAL WELLS. At East tSt. Louis, in the extreme northwest comer of the county, on the low bottom of the Mississippi River, borings and bridge foundations have penetrated 120 to 140 feet of fine sand, reaching a level about 100 feet below the low- water mark of the river before entering rock. Private wells are obtained at a depth of about 35 feet. The public water supply is pumped from the Mississippi River. At East Carondelet, also in the Mississippi bottoms, about 6 miles below East St. Louis, wells are usually obtained at a depth of about 40 feet, but Mr. H. L. Pugh has driven several wells to a depth of 60 feet. The upper 40 feet is a fine sand, but the lower 20 feet is a fine gravel or coarse sand. Piles driven at the foundation of the Meier Iron Works are thought to have struck solid rock at a depth of 90 feet, or a level nearly 60 feet below the low-water mark of the river. On the Mississippi bluff" in the northwest part of the county the loess ranges in thickness from 20 to about 50 feet, and the few wells which are made in that region are usually sunk some distance into the underlying rock. The residents usually depend upon cistern water. At Millstadt the best wells are obtained in rock at a depth of 25 to 40 feet. A test boring made at this village reached a depth of 620 feet. The water has a head 75 feet below the surface and there is only a small amount, estimated at about 4 gallons per minute. WELLS OF ST. GLAIE COUNTY, ILLINOIS. 763 At Belleville the waterworks is supplied in part from a well diilled in the valley of Richland Creek and in part by impounded water from Rich- land Creek and a tributary. The well entered rock at a depth of 42 feet after penetrating the following series of drift beds : Section of well at Belleville, Illinois. Feet. Yellow till 25 Black muck, resembling soil 2 Yellow clay 6 Blue clay 9 Total drift 42 Several prospect borings for the waterworks have been made along Richland Creek Valley, between Belleville and O'Fallon, wliich penetrate in some instances 80 feet of drift, mainlj^ till. The amount of water is scarcely sufficient to fm'nish a supply for water works, hence the use of impounded water is continued. A M^ell at the Star Bi'ewery, in the northern part of Belleville, reached a depth of 503 feet and obtained a slightly saline water, with head 80 feet below the surface. The depth of the drift is 87 feet. Coal shafts near the Louisville and Nashville depot, in the north- ern part of Belleville, penetrate mainly blue till and enter rock at depths of 40 to 80 feet, the rock surface being somewhat uneven. A coal shaft just south of Belleville enters rock at 30 feet, and there are exposures of rock within the city limits. At the village of Lebanon, in the northeast part of the county, shallow wells obtain water from gravel below clay at a depth of 30 or 40 feet. Considerable wood is found in some of the wells. There are also several deep wells in the village obtaining water from limestone at 150 to 200 feet. On a drift ridge 2 miles north of the village a well made by D. Bitzer reached a depth of 86 feet without encountering rock. The lower 46 feet was a hai-d blue till containing fragments of wood. The upper 40 feet con- sisted of alternations of clay with gravel. The altitude at this well is fully 60 feet above the railway station at Lebanon. At Summerfield rock is entered at about 35 feet, but on the plain north of this village the wells usually penetrate 50 feet of drift before entering rock. 764 THE ILLINOIS GLACIAL LOBE. A coal shaft at Mascoutah is reported in tlie Geology of Illinois to penetrate the following beds of drift: Section of coal shaft at Mascoutah^ Illinois. Feef. Soil and day -0 Sand fl Blue, gray, and red clay 50 Coarse eand with wood 6 Total drift 82 At Rentchler wells enter rock at about 40 feet, but on the drift ridges between that place and Wilderman two wells are reported to have reached a depth of 85 feet without entering' rock. The following section of thick drift is reported in the Geology of Illinois. The boring was made in sec. 20, T. 1 S., R. 6 W. : Section of a horinrjin sec. 30, T. 1 S., R. 6 W. Feet. Soil and yellow clay 14 Eeddish brown gravel and sand 28 Blue clay 83 Total drift 125 111 the vicinity of Freeburg and Smithtou rock is entered in the deeper wells at about 25 to 30 feet. The upper 5 or 10 feet is a loess or pebble- less silt, and the remainder is a brown clay containing few pebbles. There appears to be but little typical till in this locality or, for that matter, in any part of the county west and south from Belleville. At Lementon a coal boring reported in the Geology of Illinois has the following section of drift: Section of drift beds in a coal borinf/ at Lementon, Illinois. Feet. Soil 3 Yellow clay 14 Sand and gravel 1 Blue clay 20 Clay resembling soil 1 Blue and yellow clay 11 Red and yellow sand 1 Total ilrilt 51 On a di'ift ridge southwest of Lementon a well made by Mr. L. Her- mann reached a dejith of 65 feet without entering rock. The upper 23 feet was mainly till; the remainder sand and gravel. WELLS OF MONEOE COUNTY, ILLINOIS. 765 Near New Athens coal shafts and borings enter rock at depths ranging from 37 to 75 feet. A well at J. Hardy's, south of New Athens, reached a depth of 90 feet without entering rock, and several wells in that vicinity are 50 feet in depth. Southeast from New Athens rock is usually entered within 30 feet of the surface. Some of the highest points have rock at surface. MONROE COUNTY. GENERAL STATEMENT. Monroe County borders the Mississippi River below St. Clair County, and has an area of 380 square miles, with Waterloo as the county seat. The western part of the county is largely occupied by the St. Louis limestone, and is characterized by subterranean drainage through sink holes and caverns. The limestone is covered with a deposit of loess, but there is very little gla- cial drift. In the northern end of the county, near Columbia, there is a lowland occupied by Coal Measures, in which di-ift 40 feet or more in depth has been deposited. The eastern part of the county is occupied by Coal Measures and its drainage is tributary to the Kaskaskia, that stream being the eastern border of the county. The belt of drift ridges which have been traced southward tln-ough St. Clair County cross the eastern border of Monroe County, following nearly the west bluff of the Kaskaskia River. The drift on this ridg-ed belt has been penetrated in one instance 115 feet and in several instances 60 to 75 feet without reaching the rock. It is found to be partly sand and partly till. West from this ridged belt the drift is thin, seldom exceeding 20 feet. Wells are usually obtained from the rock, except along the belt of ridged drift and in the Mississippi bottoms. Strong wells are seldom obtained in the rock at less than 50 feet, and not infrequently they are 80 feet in depth. The wells in the Mississippi Valley are only 40 or 50 feet in depth, and are largely through fine sand. The wells along the belt of ridged drift vary greatly in depth, some being obtained at about 30 feet, while others are sunk to twice or thi'ice that depth. INDIVinUAL WELLS. At Columbia the wells are 20 to 45 feet in depth, the deeper ones being from the rock. A prospect boring for artesian water was sunk to a depth of 1,010 feet. It has a head 10 or 15 feet below the surface. No use is 766 THE ILLINOIS GLACIAL LOBE. made of the well at present. Exposures iu the ravines near Columbia show a deposit of loess about 12 feet in depth, beneath which there are yellow and blue clays containing a few pebbles and an occasional bowlder as well as numerous fragments of wood. The rock fragments are far less numerous than in typical till. At Waterloo the wells range in depth from 20 to 80 feet, and nearly all are from limestone. One at the mill, however, 20 feet in depth, was obtained without entering rock. A well at the electric light plant is reported to have entered rock at about 30 feet. The Manual of American Water- works (1897) reports that an impounding reservoir has been constnicted with a view to obtaining a public water supply. In the vicinity of Burksville wells occasionally reach a depth of 30 or 40 feet before entering rock. They are mainly through a nearly pebbleless clay, yellow at top and blue in its deeper portion. In the vicinity of Glasgow (Renault post-office) wells are often sunk to a depth of 50 feet. The distance to rock ranges from 10 feet to fully 50 feet, but a large amount of the clay above the rock is apparently residuary, there being very little g'lacial drift in this locality. The clay has the deep reddish brown color characteristic of clay formed from the St. Louis lime- stone. About 3 miles east of Glasgow, on a plain perhaps 75 feet lower than, the village, the drift consists of a clay with few pebbles and occasional bowlders, similar to the deposits at Columbia noted above. The depth to rock is about 20 feet. The following records of deep wells are from the drift ridges in the eastern part of the county: At W. M. Bartol's, 2 miles east of Hecker post-office, a well 60 feet ill depth is through till in the upper half and sand in the lower. A well at a schoolhouse in sec. 11, T. 3 S., R. 8 W., 60 feet in depth, was mainly through till, and one at a farmhouse a half mile farther south, 75 feet in depth, is also largely till, with wood at 72 feet. A well made by F. Yoss, in sec. 36 of this township, reached a deptli of 115 feet, and is mainly through sand. In the vicinity of Hecker, on the plain west of this ridge and about 30 feet lower elevation, wells enter rock at only 20 feet. They penetrate a brf)wn clay containing a few small pebbles. Water is usually obtained at jibout 30 feet. WELLS OF EANDOLPH COUNTY, ILLINOIS. 767 RANDOLPH COUNTY. GENERAL STATEMENT. ' Randolph County is situated on the east border of the Mississippi River, immediately below Monroe County, and has an area of ."iSO square miles, with Chester as the county seat. The Kaskaskia River leads south- ward through its western portion and drains the western half of the county. The eastern part of the county is ti'ibutary to Marys River, which enters the Mississippi just below Chester. The portion of the county on the immediate border of the Mississippi Valley stands higher than the more remote portions of the county, there being a gradual descent from the Chester to the Coal Measures formations, notwithstanding the fact that the former passes beneath the latter. The elevated tracts near the Mississippi are capped with a porous loess, but the lower tracts to the north have a silt nearly as compact as the white clay into which it graduates toward the north. The belt of ridged drift which has been traced southward through St. Clair and eastern Monroe counties crosses the Kaskaskia in northern Randolph County and passes southeast- ward through the central portion of the county just south of the villages of Sparta and Steeleville. The belt in this county has a width of scarcely a mile and has less relief than in the districts farther north, its crest being seldom more than 50 feet, and usually but 25 or 30 feet above the border tracts. On the elevated portion of the county outside the drift ridge just men- tioned there is less drift than in the lower districts to the north, and typical till is seldom found. The valleys are filled with a clayey deposit, in which there are a few pebbles and an occasional bowlder. The uplands have scarcely a trace of drift. Along the belt of ridged drift and in the district to the north typical till is quite prevalent. The thickness of drift in the northern portion of the county varies greatly because of inequalities of the underlying rock. Within the limits of the village of Sparta the thickness varies fully 100 feet. Wells frequently obtain water without entering rock at depths of 15 to 30 feet. In the elevated portion of the county the resi- dents depend largely upon cistern water, though it appears that wells may be obtained at depths of only 50 to 75 feet. 768 THE ILLINOIS GLACIAL LOBE. INDIVIDUAL WELLS!. At Red Bud, iu the northwest corner of the county, wells usually obtain water at about 40 feet, and rock is entered at 12 to 20 feet. Three deep wells have been sunk at this village, one being 1,350 feet, another 580, and a third 300 feet in depth. The deepest well is sunk on ground standing about 450 feet above tide, and water rises only to a level 20 feet below the surface. The well 580 feet in depth is on ground 30 feet lower and has an overflow. The main supply of water appears to be from the Chester sandstone, which is struck in the deepest well at 230 to 290 feet, and in other wells at corresponding depths, allowing for difference in sur- face elevatioi In the vicinity of Ruma wells obtain water from rock at about 30 feet, there being onl}^ 15 or 20 feet of loess and glacial drift. Along the belt of ridged drift in the northwest part of the county the following sections of wells were obtained: Well aections in drift in northirestem Randolph County, Illinois. Feet. H. Mehring, sec. 6, T. 4 S.,R. 7 W.; mainly till 60 H. Eabauack, sec. 6, T. 4 S.,R. 7 W.; mainly sandy till 40 P. Ackermann, sec. 1, T. 4 S., E. 8 W. ; bine till near bottom 30 John Hoy, sec. 12. T. 4 8., R. 8 W. ; sand below till 45 F. Smith, 2 miles north o'f Wheaton ; no rock, on drift ridge 100 C. Klepper, near Wheaton ; no rock, on plain 65 H. Gnebert, near Wheaton ; wood and coal in blue till 47 F. Heitzemann, sec. 13, T. 4 S., R. 8 W. ; bine till in Iciwerpart 50 G.Buck.sec. 19, T.4 S.,R.7 W.; sand below till 30 F. Rehmer, soc. 19, T. 4 S.,E. 7 W.; blue ti-ll at bottom .30 F. W. Rehnier, sec. 20, T. 4 S., R. 7 "W. ; entered blue till at 20 feet 65 D. Liddy, sec. 19, T. 4 S., R. 7 W.; mainly clay 60 E. Eggerdiiig, sec. 20, T. 4 S.,R. 7 W. ; mainly bine clay 70 Mr. Minch, sec. 28, T. 4 S., R. 7 W. ; rock at 23 feet 50 C. O'Hara, sec. 27, T. 4 S., R. 7 W. ; mainly blue clay 75 S. H. Mann, sec. 34, T. 4 S., R. 7 W. ; shale near bottom 60 J.Corseu, sec. 1, T. 5 S., R. 7 W. ; bowlders near bottom 40 J. A. Mann, sec. 1, T. 5 S., R. 7 W. ; no rock 46 Mr. Ore, sec. 5, T. 5 S., R. 6 W.; uo rock 60 .T.Steele, soc. 5, T. 5 S., K. 6 W.; no rock; blue till entered at 20 feet 75 J. Hare, sec. 4, T. 5 S.,R.6 W. ; rock at 30 feet 60 At a creamery in Houston a well 60 feet in depth does not reach rock. It enters a blue clay containing wood at about 30 feet. A well near Hous- ton, at W. McManis's, entered rock at about 57 feet. The lower 15 feet WELLS OF EANDOLPH COUNTY, ILLINOIS. 769 was blue till. A well at J. Porch's, 35 feet in depth, is mainly through till, the lower part being of blue color. A well on a knoll in sec. 10, T. 4 S., R. 6 W., obtains water in gravel at 25 feet. A well near the base of the knoll at 15 feet lower elevation enters rock at 20 feet. At Coulterville wells enter shale at 20 to 25 feet and obtain water at about 30 feet. A boring 1,117 feet in depth obtained brackish water from the Chester sandstone, of which no use is made at present. A complete record of strata penetrated is published in the Final Report of Illinois Board of World's Fair Commissioners. At Sparta the wells are seldom more than 30 feet in depth and obtain their supply from the drift. A boring 480 feet in depth made at this village furnishes water suitable for laundry purposes, but not for drinking. Several deep borings at this village obtain a supply of gas from the base of the. Chester limestone at 840 to 864 feet. The drift at these borings ranges from 34 feet to 116 feet, the thickest being on the lowest ground (J. M. Nickles). A coal shaft near Eden Station penetrated a complicated series of drift beds, a section of which appears on page 117 At Steeleville wells are usually obtained at 18 to 22 feet from sandy beds in the drift. An artesian well 312 feet in depth enters rock at 60 feet and furnishes water of good quality for drinking. The well overflows at the rate of about 2 gallons per minute. A complete section of the strata penetrated by this well is published by Professor Nickles in the report of the Illinois Board of "World's Fair Commissioners. Wells along the drift ridge both north and south from Steeleville have been sunk to depths of 40 or 50 feet without entering rock. They are mainly through till. At Shiloh Hill, wMch stands on the outer border of the belt of ridged drift, wells have been sunk to a depth of 35 feet, in some cases penetrating wood near the bottom below till. At Wine Hill, on a prominent point in the southern part of the county, a well is reported to have been sunk to a depth of 36 feet without entering rock, but rock is exposed in that vicinity at depths of 20 to 30 feet. 3ION XXXVTII 49 770 THE ILLINOIS GLACIAL LOBE. WASHINGTON COUNTY. GENERAL STATEIMENT. Washington County is situated northeast of Randolph and east of St. Clair County, with Nashville as the county seat, and has an area of 540 square miles. The Kaskaskia River forms a poi-tion of the north border and receives the di-ainage of the greater part of the county. The southeast part of the county drains southward through Beaucoup Creek, a tributary of the Big Muddy River. The uplands are coated with white clay scarcely as compact as that which is found in counties north and east. The drift masks the preglacial ridges and hills without entirely concealing them. The drainage lines are probably in large part along preglacial courses, but at levels above the old rock floor. On the uplands or preglacial ridges the drift is only 10 or 20 feet in depth, but along the main preglacial valleys it probably exceeds 100 feet. Wells usually enter rock a few feet on the uplands, but on the lowlands and along valleys they obtain water from the drift. The depth rarely exceeds 40 feet. INDIVIDUAL WELLS. At Nashville the wells range in depth from 14 to 45 feet and usu- ally enter rock a few feet. The strongest ones are estimated to have a capacity of 100 barrels a day, but many will yield not more than 10 barrels. In the vicinity of Hoyleton the drift is 15 to 30 feet in depth and many wells are sunk into the underlying rock, obtaining water at about 40 feet. They are largely thi-ough till of brownish yellow color. In the vicinity of Ashley wells range in depth from 8 feet to about 40 feet. Rock is entered at 15 or 20 feet, and the drift is mainly a brown till. In the southern part of the county the distance to rock is usually but 12 to 20 feet and wells not infrequently penetrate it a few feet. A few knolls southwest of Oakdale appear to have no rock nucleus, but informa- tion concerning them is unsatisfactory. In the northwest part of the county, on the borders of the Kaskaskia, wells are obtained without entering rock, at depths of 20 or 30 feet. WELLS OF PERRY COUNTY, ILLINOIS. 771 PERRY COUNTY. GENERAL STATEMENT. Peny County is situated south of Washing-ton and east of Randolph County, with Pinckneyville as the county seat, and has an area of 440 square miles. The greater portion of the county is tributary to the Big- Muddy River through Beaucoup Creek, which traverses the central part of the county in a north-to-south course. The Little Muddy forms the east border of the county south from the Jefferson County line. A few square miles in the west part of the county drain southwestward through Marys River to the Mississippi. The uplands are coated with compact white clay, but the valleys have a more porous deposit, forming a rich black soil. The features of this county are very similar to those of Washington, the preglacial ridges being but partially concealed by the drift and having a coating only 10 to 20 feet thick on the highest portion, while the valleys are filled more deeply so that wells seldom enter the rock. Water is usually obtained at less than 40 feet, either from the drift or rock. INDIVIDUAL WELLS. The public water supply at Pinckneyville is obtained from an artesian well around the mouth of which a large well is excavated which receives the water. The well is reported by the Manual of American Waterworks to have a depth of 2,000 feet, and to be used principally for fire protection and street sprinkling. Private wells in that vicinity are obtained at about 30 feet. Rock is occasionally entered at less than 20 feet. In the northwest part of the county, near Swanwick, wells usually obtain water at slight depth in the rock, the drift being often not more than 10 or 12 feet in depth. In the southwest part of the county wells in several instances have encountered a blue mud carrying a large amount of wood. This appar- ently underlies the pebbly clays of the drift, but whether it in turn is under- laid by a till sheet is not ascertained. In the vicinity of Duquoin wells range in depth from 15 to 40 feet, the usual depth being about 25 feet. They very seldom reach the rock. Coal shafts in that vicinity usually penetrate 30 to 45 feet of drift. The Manual of American Waterworks (1897) reports that waterworks are under construction. 772 THE ILLINOIS GLACIAL LOBE. lu the spring of 1897 a boring was begun at St. Johns by the IlHnois Central Coal and Salt Company wliich at last reports had reached a depth of more than 3,600 feet, and the drilling was still in progress. So far as the writer is aware, it is not exceeded in depth by any other boring in Illinois. The detailed record to a depth of 2,275 feet, which is given below, was furnished by John Forester, superintendent of the company, in July, 1898. Since then Mr. Forester has communicated the general results from time to time. A limestone formation forms the lower part of the sec- tion below the point where the detailed record ends. Mr. Forester states that a good quality of fresh water was found at a depth of 311 feet, but in such limited quantity that it was soon exhausted by a pump of 15-gallon per minute capacity. -At 520 feet water was encountered which showed 15 per cent salt. Below this depth the sahnity gradually increased until at 980 feet it reached 34 per cent. This water was cased out at 1,000 feet, and A^ery little more was encountei'ed until a depth of 1,604 feet was reached, when a vein of water with 38 per cent salt was struck. The well continued to yield this water until a bed of "fii-e clay" was reached at 1,949 feet. After passing through 20 feet of fire clay another yield of water with 38 per cent salt was found, which continued to a bed of shale at 2,026 feet. No more water was found until a depth of 2,271 feet was reached, when a vein of the same salinity was sti'uck. At this depth there was apparently a crevice in the rock lined with crystals of calcite. As yet no identifications of the geological formations have been made. Temperature tests were made by Mr. Forester, in March, 1899, when the boring had reached a depth of 3,600 feet. After an exposure of two hours the thermometer registered 93*^ F., and after an exposure of twenty-four hours 101° F. Log of deep boring at St. Johnu, Illmoia. Glacial drift . . . Lime rock Sandy shale . - . Shale and co.al Sandy shale . . . Clay shale Sandy shale . , .Sand lock Thick- Feel. 42 3 16 10 25 30 80 15 Septl ■ Feet. 1 0- 42 42- 45 45- 61 61- 71 1 71- 96 1 96- 126 126- 206 206- 221 Sandy shale Fire clay and shale Shale with partings Sand rock, frt'sli water Lime rock Sand rock, 15 per cent salt.. Saudy shale Sand rock Thick- 11 ess. Depth. Feet. 23 12 55 178 31 15 28 15 1 Feet. 221- 244 244- 256 256- 311 311- 489 489- 520 520- 535 535- 563 563- 578 WELLS OF JEFFERSON COUNTY, ILLINOIS. Lofi of deep horing at St. Johns., Illinois — Continued. 773 Saudy shale. Lime rock . . . SaBdrock... Shale Saud rock... Lime rock... Sand rook.. . Clay shale . . Sandy shale - Mixed shale - Lime rock . . . Shale Lime rock.. . Clay shale . . Lime rook Sandy shale . Clay shale . . Sandy shale . Lime rock . . . Sand rock . . . Lime rock . . . Sandy shale . Sand rock... Sandy shale . Lime rock Eed marl . . . . Saud rock... Sandy shale . Sand rock... Soft shale . . . Sand rock . . . Blue lime . . . Sand rock .. . Thick- ness. Feet. 32 8 25 13 10 3 10 30 35 35 16 20 25 15 5 15 40 67 20 20 10 22 13 ■ 20 20 4 39 40 90 10 10 Depth Feet. 578- 610 610- 618 618- 643 643- 656 656- 666 666- 669 669- 679 679- 709 709- 744 744- 779 779- 795 795- 815 815- 840 840- 855 855- 860 860- 875 875- 915 915- 982 982-1, 002 1, 002-1 1, 022-1 1, 032-1 1, 054-1 1, 067-1 1, 087-1 1, 107-1 1, 111-1 1, 150-1 1, 190-1 1, 280-1 1, 290-1, 1, 300-1 1, 305-1 022 032 054 067 087 107 111 150 190 280 290 300 305 310 Shale Sand rock Shale Eed marl Shale Lime rook Shale Sand rock Lime rock Sand rock Lime rock Shale with partings Lime rock Shale Sand rock Shale, mixed Lime rock Sandy shale Lime rock Shale Lime rock, 38 per cent .*alt.. Shale Lime rock, 38 per cent salt . . Fire clay or shale Lime rock with partings Shale Lime rock with partings Sandy lime rock Light gray lime rock Spar, calcite crystals Light gray lime rock, hard . . Light gray lime rock, soft . . Mainly limestone to 3,600 feet Thick- Feet. 10 10 14 4 4 16 7 14 10 15 6 20 35 23 20 19 4 8 40 15 92 3 250 20 57 10 102 160 63 4 498 227 600 Depth. Feet. 1, 310-1, 320 1, 320-1, 330 1, 330-1, 344 1, 344-1, 348 1, 348-1, 352 1, 352-1, 368 1, 368-1, 375 1, 37.5-1, 389 1, 389-1, 399 1, 399-1, 414 1, 414-1. 420 1, 420-1, 440 1, 440-1, 475 1, 47.5-1, 498 1, 498-1, 518 1, 518-1, 537 1, 537-1, 541 1, 541-1, 549 1, 549-1, 589 1, 589-1, 604 1, 604-1, 696 1, 696-1, 699 1,699-1,949 1, 949-1, 969 1, 969-2, 026 2, 026-2, 036 2, 036-2, 148 2, 148-2, 208 2, 208-2, 271 2, 271-2, 275 2, 275-2, 773 2, 773-3, 000 3, 000-3, 600 Altitude of well mouth, 463 feet above tide. JEFFERSON COUNTY. GENERAL STATEMENT. Jefferson Countj is situated east of Washington and Perry counties, about midway between the Mississippi and Wabash rivers, with Mount Vernon as the county seat, and has an area of 580 square miles. The 774 THE ILLINOIS GLACIAL LOBE. di-ainage is mainly soutliward tkrough the Big Muddy River. A small area in the northeast part is tributary to Skillett Fork, which flows southeast to the Little Wabash. The uplands are coated with white clay, which furnishes a slow absorbent for the rainfall. The portions of the county remote from the main drainage lines have imperfect drainage, the excess of rainfall being disposed of largely by evaporation. The glacial deposits are generally thin and but partially conceal the preglacial ridges and valleys. They consist cliiefly of a brownish yellow till. Throughout much of the county wells are reported to penetrate rock a few feet for the best supply, but weak wells are often supplied fi-om the diift. No attempt was made to collect well records in the county. The Manual of American Watei-works reports that at Mount Vernon the public water supply is from impounded water. The drift in the vicinity of that city is only 10 or 15 feet in depth. WAYNE COUNTY. GENERAL STATEMENT. Wayne County is situated in the southeast part of the State, with Fairfield as the county seat, and has an area of 720 square miles. The Little Wabash River leads southward near the eastern border of the county and Skillett Fork leads southeastward thi'ough the southwestern portion. The uplands are covered with a silt deposit, but as the}" are more hilly than the counties to the north and west the water is drained to the lowlands readily, and a more compact deposit is found on the lowlands than on the hills or uplands. The drift is generally a thin coating averaging scarcel}'' 15 feet in depth on the higher parts of the county. In the lowlands and along val- ley's there is probably a greater depth. The thickness, however, has not been tested by well borings, the wells being obtained at comparatively slight depth from sandy beds in the drift. The di-ift consists usually of a brown till, which sets in below the white clay or surface silt at a depth of 6 or 8 feet. INDIVIDUAL WELLS. In the northwest part of the county, in the vicinity of Rinard, Blue Point, and Johnsonville, a large percentage of the wells enter rock at about 10 feet and obtain water at 30 to 40 feet or less. WELLS OF EDWARDS AND WABASH COUNTIES, ILLINOIS. 775 In the vicinity of Cisne the drift has a thickness of 20 feet or more. Between Cisne and Fairfield, however, rock is often entered at 10 or 12 feet. The drift is also thin from Fairfield westward to Wayne City. In the city of Faii-field the drift ranges in thickness from 8 to about 20 feet. Wells usually obtain water from rock at 25 feet or less. A few are drilled to a depth of 50 or even 70 feet. East from Fairfield, in the vicinity of Meriam, wells enter rock at 10 feet or less. At Grolden Gate Station, which stands on a low hill in the Little Wabash Valley, rock is struck at 16 to 20 feet. EDWARDS AND WABASH COUNTIES. GENERAL STATEMENT. These two counties, with a combined area of but 440 square miles, are situated east of Wayne County and border the Wabash River. Albion is the county seat of Edwards, and Mount Carmel tlie county seat of Wabash County, The Bonpf^s River forms the dividing line between the counties and flows through a broad bottom deeply filled with drift or allu- vium. This stream receives the drainage of much of both counties and carries it southward to the Wabash. The western portion of Edwards County drains into the Little Wabash River and the eastern portion of Wabash County into the main Wabash River. Both counties are covered thinly with diift excejit in lowlands or valleys, and the preglacial ridges and hills stand 50 to 100 feet or more above the neighboring lowlands. There is a silt covering these hills and ridges, but it is more porous than the white clay. On the lowlands and flat areas within these counties the white clay apjDears in its compact phase. Wells are usually obtained on the loAvIands at a depth of 20 feet or less without entering rock. On the uplands few wells are obtained without penetrating rock. The depth, however, is moderate, seldom exceeding 50 feet. INDIVIDUAL WELLS. Near Ellery, in western Edwards County, at the base of the east blufl" of the Little Wabash, rock is usually entered at 10 to 20 feet, and wells obtain water at about 30 feet. On the bluif east of Ellery, at an altitude 60 feet above the station, wells enter rock at about 10 feet and obtain water at 40 or 50 feet. 776 THE ILLINOIS GLACIAL LOBE. At the villag'e of Albion, whicli is situated ou the divide between the Bonpas and Little Wabash, at an altitude about 150 feet above the streams, rock outcrops in numerous places, and the g'eneral thickness of the drift coating scarcelj" exceeds 5 feet. "Wells are obtained at deoths of 40 or 50 feet, but the residents depend mainh- upon cisterns. In the valley of Bonpas River, near Brown Station, a well reached a depth of 61 feet without entering- rock. It is reported to be mainly tlii'ough sand with few if any pebbles. At West Salem rock is visually entered in wells at 20 feet or less, and water is obtained at 30 or 40 feet. At Mount Carmel the supply for the waterworks is obtained from a well in the Wabash Valley, which obtains Avater at the surface of the rock at a depth of 25 feet. Wells on the uijlands in the cit}" obtain water fi'om the rock at depths of 25 to 40 feet, those on the lowlands near the Wabash obtain water from di-ift at a deptli of 15 to 25 feet. West from Mount Carmel, in the vicinity of Maud and Belmont stations, wells in some cases obtain water in drift at 15 to 25 feet, but often enter the rock a few feet. At Friendsville rock is struck at 12 to 15 feet and wells obtain water at about 30 feet. In a lowland tract 2 miles northeast of Friends\-ille, known as Crawfish Flats, wells 40 feet in depth do not reach rock, and logs are sometimes struck near the bottom. WHITE COUNTY. GENERAL STATEMENT. White County is situated on the west border of the Wabash River, in the southeast part of the State, immediately below Edwards County, and has an area of 500 square miles, with Carmi as the county seat. The Little Wabash River traverses the county from north to south nearly centrally, and Skillett Fork, the main tributary of Little Wabash, lead.s southeast- ward across the northwestern part of the county and enters the Little Wabash just above the town of Carmi. In this county the streams are bordered by Ijroiid lowlands, filled apparently to considerable de})th with glacial or alluvial deposits. The uplands are hilly and carry a very thin coating of di'ift, rock usually being entered within 10 feet of tlie surface. The entire countA' appears to have been covered by the ice sheet, for drift is found in the vicinity of the Wabash River both to the east and south of WELLS OF WHITE COUNTY, ILLINOIS. 777 the county limit in Posej^ County, Indiana, and Gallatin County, Illinois. The drift is mainly a brown till on which there is a coating of silt 6 or 8 feet in depth, which is probably the southward extension^ ot the white clay, though a more porous deposit. Wells are obtained on the uplands at moderate depths in the rock. On the lowlands they are shallow, seldom exceeding 30 feet, and obtain water from gravel or sand. Along the Wabash there is an extensive bottom underlain by fine gravel which affords water at about the level of the river. INDIVIDUAL WELLS. The jxiblic water supply at Carmi is pumped from the Little Wabash River. On the hills bordering the city wells enter rock at about 1 feet and water is obtained at '26 to 40 feet. ■ These conditions prevail southwestward to the limits of the county. In the south part of the county, in Heralds Prairie Township, there is considerable lowland, and wells occasionally reach a depth of 40 feet without entering rock; they are mainly through till. In the Wabash bottoms, in the vicinity of Concord, (Emma post-office) the wells range in depth from 15 to 40 feet and are mainh^ through sand. About 3 miles east, of this village wells obtain water in gravel at a depth of biit 12 to 20 feet. In the vicinity of Crossville and Phillipstown, northeast from Carmi, wells obtain water at about 25 feet in sand. A section near Phillipstown is noted in the Greology of Illinois, which exposes loess with fossils, 20 or 30 feet, beneath which is drift with pebbles and small granite bowlders, 35 feet. At Grrayville, in the northeast corner of the county, the loess has a thickness of 16 or more feet and is underlain by a thin sheet of till. Wells usually enter the rock, obtaining water at 30 to 40 feet. The waterworks obtains its supply from the Wabash River. ^ HAMILTON COUNTY. GENERAL STATEMENT. Hamilton County is situated west of White County, in the southeastern portion of the State and has an area of 440 square miles, with McLeans- boro as the county seat. Its southeast portion is drained by the north fork ' Manual of Anierioau Waterworks. 1S97. 778 THE ILLINOIS GLACIAL LOBE. of Saline River and the northern portion is tributary to Skillett Fork of Little Wabash River. The lowlands are filled to considerable depth with drift, but the uplands, like those of White and the neighboring counties on the north and east, have a very thin drift coating, averaging scarcely 10 feet. The surface of the uplands is uneven, the preglacial ridges and hills being concealed but little by drift. A coating of silt covers the county, but it is much more porous than that of the more level counties on the northwest. WELLS. The wells of this county, as in neighboring counties, obtain water at depths of but 20 to 40 feet or even less, those on the uplands being gener- ally into rock a few feet, while these on the lowlands are obtained without reaching the rock. No records of individual wells were collected. The village of McLeansboro has a fire protection in cisterns distributed around the public square. There are also four tubular wells in the village, Avhich, the mayor reports, have hard water, unfit for domestic use. The greater part of the citizens depend upon cistern water. FRANKLIN COUNTY. GENERAL STATEMENT. Franklin County is situated south of Jefterson, about midway between the Wabash and Mississippi rivers, with Benton as the county seat, and has an area of 430 square miles. It is drained southwestward by the Big Muddv River, which crosses the west-central portion of the county. Its topography and general characteristics are so similar to Hamilton County that further description is scarcely necessary. The wells on the uplands usually enter rock at a slight depth and penetrate it a few feet. If a good quality of water is not obtained cistern water is substituted. In the flats of the Big Muddy Valley, in tlie south- west part of the county, wells may be obtained without entering the rock. JACKSON COUNTY. GENERAL STATEMENT. Jackson County is situated on the east border of the Mississippi River below Randolph County, with Murpliysboro as the county seat, and has an WELLS OF JACKSON COUNTY, ILLINOIS. 779 area of 580 square miles. Big- Muddy River traverses its southern portion and Beaucoup Creek divides the northern portion nearly centrally. This county, like Randolph, has an elevated limestone tract along the Mississippi bluffs, from which there is a descent northeastward to the plains underlain by the Coal Measures. The elevated portion of this county has such a broken surface that it is but sparsely settled. At the south it extends beyond the glacial boundary and preserves all the ruggedness of the preg-lacial topography. The western portion appears to have been covered by the ice sheet, but the drift only partially fills the preglacial valleys. The belt of ridged drift which has been traced southeastward across Randolph County to the border of this county is represented by occasional low ridges and knolls along the north border of the elevated tract just dis- cussed as far east as the plain bordering Beaucoup Creek. The best development is found 1 to 4 miles southeast of Ava, along the turnpike leading from Ava to Murphysboro. The belt has not been identified in the eastern portion of the county. Northeast from this ridged belt there is generally present a sheet of typical till 20 to 40 feet or more in depth, and a similar deposit is found in the lowlands of the northeastern part of the county. The wells often penetrate a bed of blue silt containing wood at depths of 30 feet or more, beneath the pebbly glacial clays. Several instances are noted in the Geology of Illinois, and other instances came to the writer's notice, but no exposures of the silt were found b}^ the writer. On the elevated and hilly portions of the county the residents depend largely upon cistern water, but a few wells have been obtained at moderate depth. In the lower portions of the county wells are obtained at 20 to 50 feet, often without entering rock. Those in the Mississippi Valley are 30 to 40 feet in depth and mainly through a fine sand. INDIVIDUAL WELLS. The wells at Campbell Hill, in the northwest part of the county, have in a few instances been sunk into rock, which is reached at a depth of about 40 feet. The majority, however, obtain water from the glacial drift. Records of wells near this village appear in the Greology of Illinois, in which a blue mud containino- wood is struck below the g-lacial di-ift at depths of 30 to 35 feet. 780 THE ILLINOIS GLACIAL LOBE. At Ava a coal boring- is thought to have struck rock at 57 feet, but the deepest Avells at this village are about 60 feet and do not enter rock. They are mainly through a pebbly clay witli which thin sand beds are associate;!. A well at D. R. Wills's, on the crest of the drift ridg-e, 3 miles southeast of Ava, reached a depth of 65 feet without entering rock. Its altitude is fully 300 feet above the Mississippi River. Within 2 miles east from this well rock is struck at only 15 to 25 feet, on gi-ound fully as elevated as the drift ridge. Immediately outside the drift ridge there is scarcely any drift covering the rock. At Murphysboro wells are usually obtained at 15 to 30 feet from sand below clay. Coal borings and the well at the Murphysboro brewery pene- trate considerable sand and seldom reach rock at less than 100 feet. The boring at the brewery penetrated 132 feet of drift. An artesian well was sunk at this city many years ago which reached a depth of 1,800 feet. A flow of salt water was struck at about 1,300 feet. The waterworks obtains its supply from Big Muddy River. At Carbondale the wells are usually obtained at 15 to 20 feet in a sandy clay near the base of the drift. A well at the Newell House entered rock at 22 feet and reached a depth of 50 feet. A well at the electric light plant is reported to have penetrated 44 feet of di-ift, mainh^ a clay with few pebbles. At Elkville, in the northeast part of the county, wells are obtained at about 20 feet from sandy beds associated with the till. A coal boring at this village, reported in the Geology of Illinois, entered rock at 34 feet. WILLIAMSON COUNTY. GENERAL STATEMENT. Williamson County is situated east of Jackson, with Marion as the county seat, and has an area of 440 square miles. The western half of the county is tributary to Big Muddy River and the eastern to Saline River. With the exception of the south border, which is hilly and unglaciated, this county is a low plain covered to a moderate depth with glacial drift. The thickness of the drift apjiears to be slightly greater than in counties to the north, l)ut it is not often more than 40 feet. The average is probably 25 feet. A capping of silt nearly as compact as the white clay covers the WELLS OP WILLIAMSOS^ COUNTY, ILLIISrOIS. 781 glacial di-ift. Where drainage lines are not well developed, tlie excess of rainfall is largely disposed of by evaporation. The poorest drainage is found in the northwest part of the county, where there is an extensive plain standing but a few feet above the level of Big Muddy River. In this portion of the county wells usually obtain water without entering rock, but in the eastern and southern portions the majority enter rock. INDIVIDFAL WELLS. In the vicinity of Marion wells are obtained in sand below till at about 20 feet. They penetrate 6 or 6 feet of white clay, then enter a yellow till which extends to the water-bearing sand. In a few cases blue till is entered at about 20 feet. These conditions prevail over the portion of the county north and west from Marion. In the portion of the county south and west from Marion low hills with rock nucleus rise above the level of the drift filling, but the plain tracts among these hills are filled to a depth of 50 to 75 feet or more with glacial drift. A well near Cottage Home, in the southwest township of the county, within 3 miles of the glacial boundary, j^enetrated 68 feet of drift, mainly blue till, and obtained water without entering rock. Several wells in that vicinity are 30 to 40 feet in depth without entering rock. In the eastern part of the county there are low hills with rock nucleus on which the drift coating is only a few feet in depth, but among these hills the wells often reach a depth of 30 feet without entering rock and are largely tln-ough a brown till. In the unglaciated portion on the south border of the county there are few residents, and these depend chiefly upon cistern water or springs. SALINE COUNTY. GENERAL STATEMENT. Saline County is situated east of Williamson and has an area of 380 square miles, with Harrisburg as the county seat. It is drained by Saline River, whose south fork passes eastward across the southern j)ortion of the county and whose north fork crosses the northeast corner. The portion of the county south of the south fork is an elevated and hilly region, largely unglaciated ; the remainder of the county is a low district with small hills 782 THE ILLINOIS GLACIAL LOBE. and ridges having I'ock nuclei, but which rise only 25 to 50 feet above the bordering lowlands. The streams are generally bordered b}' broad low- lands, poi'tious of which are thinly covered with drift, as are also the low hills and ridges just mentioned. There are probablv filled valleys travers- ing these lowlands, in which the thickness of drift is greater than on the remainder of the county. In tliis county, as in the neighboring counties on the north and west, the drift is covered with a pebbleless silt several feet in depth. On the hills and ridges this is less compact than the white clay in districts to the north, and the lowland tracts also have usually a more porous silt than the typical white clay. The glacial di-ift consists mainly of a brown till, but where it reaches a dejDth of 30 feet a blue till is usually found at bottom. The wells are often sunk into the rock a short distance, and few strong wells were found which obtain a supply from the drift. Their depth seldom exceeds 40 feet. INDIVIDUAL AVELLS. At Texas City, in the northeast part of the county, a well sunk by T. W. Overton reached a depth of 302 feet. Water rises within 8 feet of the sui'face. An inflammable gas was struck at about 240 feet, which is estimated to have a pressure of 75 pounds to the square inch. At Eldorado wells enter rock at about 20 feet after penetrating a few feet of surface silt and a shghtly pebbly clay. "Water is usually obtained within 30 or 40 feet. A well at Louis Pettinger's, 2 miles east of Eldo- rad(j, on a low drift knoll, reached a depth of 46 feet without entering rock. The lower part was through a blue clay, probabl}' till. A well made by D. Westbrook, on a low drift knoll 2 miles northeast of Eldorado, reached a depth of 40 feet without entering rock, and a similar depth was reached on a knoll 1 mile north of Eldorado in a well made by L. Lyson. These knolls stand only 10 to 20 feet above the bordering plane tracts. In the vicinity of Raleigh the shallower wells obtain water in ih-ift, but a few wells have been sunk into rock, which is entered at about 30 feet. In the })ortion of the county west from the meridian of Raleigh there are numerous low hills with rock nuclei, and wells visually enter rock within 10 or 15 feet of the surface. These conditions continue southward past HamsVjurg to the elevated ridge on the border t»f the ct)imty. On this ridge the residents depend largely upon cisterns and springs. WELLS OF GALLATIN COUNTY, ILLINOIS 783 GALLATIN COUNTY. GENERAL STATEMENT. Gallatin County is situated on the soxitheast border of the State, a portion of its east boundary being- the Wabash and a portion the Ohio River. It has an area of 349 square miles, with Shawneetown as the county seat. The eastern third of the county is so low as to be extensively covered with the sands brought down by the Wabash and Ohio rivers. The northwestern portion Avhich is drained b}^ the north fork of Saline Eiver is largely a low district only 10 to 20 feet higher than the Wabash and Ohio bottoms. There are, however, a few hills with rocky nuclei which, rise to a height of 50 feet or more above the bordering lowlands. The southwest corner of the county is occupied by a high and hilly unglaciated tract, the continuation of that noted in southern Saline County. There is a group of hills near Shawneetown Avliich stand 100 to 150 feet above the Ohio River that are entu-ely surrounded by the low bottoms of the Wabash and Ohio rivers. With the exception of the hilly district in the southwest part of the county and the group of hills near Shawneetown, just noted, the county is covered with glacial or alluvial deposits. It is probable that the glacial boundary lies a few miles west of the Ohio and Wabash rivers, except at the extreme north border of the county, where it apparently crosses the Wabash. The drift on the lowlands bordering the Wabash and Ohio bot- toms is mainly sand, and it is difficult to determine whether it is of dii-ect glacial deposition. There are in places low knolls and ridges which are composed of sand; they may be largely the product of the wind. INDIVIDUAL WELLS. In the vicinity of Omaha, in the northwest part of the county, the drift consists of a typical till. Wells on the low hills and ridges usually enter rock at 15 or 20 feet, but those on the lowlands have penetrated 35 or 40 feet of drift without entering rock. Not infrequently a black muck is found below till on these lowlands at a depth of 20 to 35 feet. Wells near the station in Omaha strike it at about 35 feet, but farther east it is entered at less depth. Between Omaha and Ridgway a well was driven to a depth of 98 feet without reaching rock, mainly through sand. Wells east and northeast of 784 . THE ILLIiSrOIS GLACIAL LOBE. Hidg'way are in several instances sunk to a depth of over 50 feet, mainly througli sand. Wells west and northwest from this village are usually sunlv through till, and one well 3 miles west is reported to have reached a depth of 75 feet without entering rock, mainly through till. A blue till was entered at about 25 feet. Near Cottonwood rock is entered at only 20 feet and the drift is largely sand. Rock is found at slight depth between Cottonwood and New Haven. At Shawneetown wells usuall}^ obtain- water at 25 to 40 feet in a sandy gravel An oil boring entered rock at 112 feet. A well at the fair grounds 86 feet in depth did not reach the rock. THE UNGLACIATED COUNTIES OF SOUTHERN ILLINOIS. CiENEKAL STATEMENT. There are seven counties in the southern end of the State — Hardin, Polk, Johnson, Union, Alexander, Pulaski, and Massac — which are situated outside the limits of the glacial boundary. The four first named are trav- ersed by an elevated ridge, known as the "Ozark uplift," which passes nearly east to west from the Ohio River just below Shawneetown to the Mississippi River at Grand Tower. The crest of this ridge is generally about 400 feet above the Ohio and Mississippi rivers, but occasional knobs alonPT it reach an elevation of 500 and even 600 feet above the river. The most rugged portion of the ridge is found in the northern 6 or 8 miles of these counties and extends slightlj^ into the counties on the north — Jackson, Williamson, Saline, and Grallatin, as noted above. South from this elevated and rugged portion of the ridge there is a somewhat hilly tract with lower altitude, which extends to the lowlands covered by Tertiary gravel, which occupy much of the three southern coun- ties of the State — Alexander, Pulaski, and Massac. Although not covered by the ice sheet, this district has received deposits of glacial age which aflPect to some extent the condition of drainage and the character of the soil. The Ohio and Mississippi valleys have been filled with deposits of sand and fine gravel to a depth ]irol)ably not less than 100 feet. There are also alluvial de})Osits outside the line of the present Ohio which were jji-obably made at the time of the filling of the main valleys. A broad valley, known WELLS OP SOUTHERN ILLINOIS. 785 as the Cache, now largely a cypress swamp, leads westward from north- western Massac County across northern Pulaski and then turns south into the Ohio along the line of Alexander and Pulaski counties. From the head of this swamp there is a well-defined connection with the Ohio River in a low plain leading southeast to Metropolis, across the central portion of Massac County. This plain has been built to a level about 70 to 75 feet above the Ohio River, or 20 to 25 feet above the highest present flood stages of the stream. Its freshness of topography is decidedly in contrast with that of the bordering Tertiary formations, in which there has been great erosion. As noted above (p. 528), this channel was probably silted up either at the lUinoian or the lowan stage of g'laciation. In addition to the alluvial deposits found in the valleys and lowlands there is a coating of loess found on all except the most rugged portions of the uplands. This loess has a general thickness of about 12 feet on the border of the Ohio and fully twice that amount on the border of the Mis- sissippi, while in the interior portions, as on the glaciated districts to the north, its thickness is only 5 or 6 feet. Whether the loess originally cov- ered the highest and most rugged parts of this ridge is not known. If originally present it has now been largely removed. A more critical study may perhaps develop decisive evidence on this point. INDIVIDUAL WELLS. On the most rugged portions of the ridge there are very few residents and these depend chiefly upon cistern water. On the lower tract, between the crest of the ridge and the Cache, there is a limestone district in which wells are usually obtained at 40 to 60 feet or less. In the district covered by Tertiary deposits wells are usually found at moderate depth, seldom exceeding 40 feet. The wells on the lowland connecting the Ohio with the Cache near Metropolis have in several instances reached a depth of 60 to 75 feet, but in the neighborhood of the Cache they obtain water at much shallower depth, often being but 15 to 20 feet deep. Along the Mis- sissippi Valley the wells are usually driven to a depth of 30 or 40 feet. It is reported that Mr. Bolin Sublette, an early settler in Union County,, dug a well near "Wolf Lake Station to a depth of about 80 feet, reaching a level at least 50 feet below the low water of the Mississippi River. It is MON XXXVIII- 50 786 THE ILLI^^TOIS GLACIAL LOBE. also reported that a log was fouud near the bottom. This well iudicates that the present stream is flowing- at a level considerably higher than the preglacial rock floor. At Anna the wells are 20 to 60 feet in depth, the majority being about 40 feet, and obtain water in limestone. The city authorities are considering the advisability' of constructing waterworks. The best wells are estimated to have a capacity of about 100,000 gallons a day. The source for the piiblic water supply naight therefore be found in these wells. At Vienna wells are ol^tained at 25 to 60 feet in limestone, tlie usual depth being about 50 feet. An average well is estimated to yield about 12 baiTels of water a day. The village of Thebes stands in a portion of the Mississippi Valley which is postglacial, and wells obtain water at the top of the rock at a depth of only 20 feet. The residents depend larg-eh' ujion cistern water. At Cairo the watej-works are supplied from the Ohio River. Excavated wells are not allowed witliin the city limits. Driven wells have been sunk to depths of 70 to 200 feet. No solid rock is reached at the latter depth. The city engineer reports that good Avater is obtained at about 70 feet. The following section of a boring for a bridge, by the Illinois Central Rail- road Company, was furnished by the city engineer. The surface elevation is 45 feet above low water at the mouth of the Ohio. The boring therefore reaches a level 80 feet below the low-water mark: Section of boring for hridtie of lUinois Central Railroad at Cairo, Illinois. Feet. Muil and sand 15 Fine sand 40 Coarse sand and gravel 30 Coarse sand, gravel, and fragments of sand rock 15 Fine sand and gravel 10 Fine wbite sand : 15 Total depth 125 This boring sliould l)e compared with borings made by tlie United States Army Engineers at ]ioiuts between Cairo and Vicksburg.' At Metropolis tlie pulilic water supply is pumped from the Ohio River, but there are numerous wells about 40 feet in depth. These wells • See reports of the Chief of Engineers, United States .\ruiy, for 1877, 1878, and 1879; also Kei)ort of Mississippi Kiver Commission, 1881, pp. 171-239. WELLS OF SOUTHERN ILLINOIS. 787 are through a sUt or clay for a few feet in their upper portion, but the greater part of the section is sand. Gravel is entered near the bottom, which is probably Tertiary. As noted above, wells on the low plain leading from Metropolis northwest to the Cache are occasionally sunk to a depth of 75 feet. They are largelj?^ through a fine sand, but enter gravel at bottom, probably Tertiary. At Olmsted wells obtain water in some cases at 35 feet, but a Avell on a low hill northeast of the station, standing 140 feet above the Ohio, reached a depth of 81 feet. The lower 60 feet was entirely a Tertiary gravel. At Brooklyn (Pellonia post-office) the river bank is about 45 feet above low water of the Ohio and there is Tertiaiy gravel to within 15 feet of the top. Wells obtain water in this gravel near the river level. In the vicinity of Rosebud, in Pope County, where the altitude is nearly 260 feet above the river, there is a heavy deposit of Tertiary gravel in which wells have occasionally reached a depth of 100 feet without enter- ing rock, but on neighboring farms at similar altitude rock may be entered at 25 or 50 feet. At Grolconda wells are usually obtained in the Ohio bottoms at a depth of 30 to 40 feet. A well made by Mr. George Boos, at a level probably 65 feet above low water in the Ohio, reached a depth of 136 feet without entering rock. The best water vein was at about 40 feet. Wells on the bluff also reach water at only 30 or 40 feet, in sandstone. CHAPTER XV. SOILS. SOURCES OF SOir, MATERIAL. The principal sources from which the soils of the region under discus- sion are derived are the glacial drift and the loess, with its associated silts of glacial age. The underlying rocks are indirectly a source of much material, since their decomposed surface ^lortions were incorporated in the di-ift, but they constitute a minor source so far as direct contribution is con- cerned. Lakes and streams attending the melting of the ice sheet have deposited material in considerable amount, and it is thought that the wind also has been influential in distributing- fine material over portions of the surface of the region. The present streams are also a source for soil in the districts over which they spread in their flood stages. . The preceding discussion has shown that portions of the surface of this region date from the lowan stage of glaciation, namely, the portions cov- ered by the lowan loess and associated silts, and the portion in which the lowan till sheet forms the surface. These deposits form the surface of con- siderably more than one-half the region. In the remainder of the region the Wisconsin drift constitutes the main part of the surface, though small areas have been occupied by lakes and streams since the withdrawal of the Wisconsin ice sheet. The area covered by Lake Chicago is the most con- spicuous illustration. CLASSES OF SOIL. Inasmuch as soils are largely comjDosed of fragments of rock material, they are naturally dependent to a certain degree upon the character of the rock from which they are chiefly derived. This is especially true in ungla- ciated regions, but in glaciated regions also the soil is found to depend upon the character of the underlying deposits. There are several modes of classi- fication in use, based usually upon either chemical constitution or physical texture or characteristics. The classification which seems to best serve our purpose is based mainly upon physical characteristics. This classification also sets fortli what appear to be the characteristics of chief importance. The elaborate investigations made by Prof Milton Whitney, of the United 788 SOILS OF ILLINOIS. 789 States Department of Agriculture, on the Mar3^1and soils indicate that the texture and physical conditions of the soils are of even more importance than the chemical composition. On this matter Professor Whitney has written as follows:^ The prevailing ideas of plant nutrition bave been based mainly upon the chemical coiiiijositioii of soils. When it was found that the chemical composition of a soil and plant did not show what was lacking in the soil for a large crop, it was held that only a small iiart of the plant food in the soil is at any one time in a form of combination which is available to plants; that the available plant food never accumulates as such in the soil, but quickly reverts to more insoluble forms, which are unavailable to plants. Accordiug to this idea the exhaustion of soils by continued cropping is due to the actual loss of available plant food removed by the crop or converted into an unavailable form by chemical changes in the soil. The chief use of fertilizers is to supply the plant with food which the soil fails to furnish. The reason certain plants do better ou certain kinds of soil is assumed to be due to the fact that plants vary greatly in their powers of gathering their food from the soil and air, and that thus a rye plant would do well on a soil too poor to give a good yield of wheat. Our investigations on the Maryland soils seem to show, however, that the texture and the physical conditions of the soil are of more importance than the chemical composition. It appears that under favorable conditions of moisture and temperature plants can readily gather sufficient food material from nearly all soils; but if these conditions of moisture and heat are changed, the development of the plant will be greatly changed and it will take up more or less food Irom the soil. Soils differ greatly in their texture — that is, in the amount of sand and clay which they contain — and, as we have seen, this controls very largely the supply of moisture which they can maintain for the crop with a given amount of rainfall. If there are 4 inches of rainfall a month, the coarse sandy soil will allow most of this to run through very quickly, so that there may not be more than 5 or G per cent of water held in the soil for the crop, or, say, about 100 tons of water per acre 1 foot deep; and when this water is used up, the soil has comparatively little power to draw up more water from below for the use of the crops. With a compact clay soil, on the other hand, the water passes downward very slowly, and the soil will maintain about 18 or 20 per cent of its weight of water for the crop, or about 100 or 500 tons of water per acre 1 foot deep. In the dry season, also, the clay soil has more power of drawing up water from below and maintaining this supply. If a florist should give a plant four times as much water as he gives another plant of the same kind, the two plants would develop very differently, and he uses this constantly to produce any kind of develop- ment he desires. If it is desired to have the plant flower or fruit, the soil is kept rather dry and cool. If it is desired to i)roduce large leafy plants, the soil is kept much wetter and warmer. To have equal success with different kinds of plants the amount of water must be carefully regulated according to the needs of the plant. Some plants require a mucli more abundant sui)ply of water than others. This con- trol of moisture and temperature is far more important than the mere chemical com- position of the soil. ' Kept. Illinois Board of WorlcTs Fair Coramissioners, 1893, pp. 94-96. 790 THE ILLINOIS GLACIAL LOBE. The texture of our various soils being diflereut, they are enabled to maintain a variety of conditions of moisture, and they partake somewhat of these artificial con- ditions in a greenhouse, the conditions in each of the soils being best suited to the needs of certain classes of plants. The amount of moisture which a soil can maintain for a crop, under given cli- matic conditions, will depend mainly, (1) upon the amount of space in the soil in which water can enter; (2) upon the extent of subdivision of this space — that is, upon the number of grains of sand and clay there is in a given volume of soil; (3) upon the arrangement of these grains, for, as already remarked, if the grains are symmetrically arranged, so that the spaces shall all be of uniform size, water will move through the soil much slower than if the spaces are of very unequal sizes; (4) upon the amount and condition of the organic matter in the soils. The grains of clay are so exceedingly small that their number vastly exceeds the number of the grains of sand and silt, so that the percentage of clay practically determines the extent of subdivision of the space, and it is thus the most important ingredient of the soil. Ill Illinois and adjacent districts the following- classes of soil are repre- sented: (1) residuary soils, or soils formed from the underlying rock; (2) stony, or glacial clays; (3) gravelly soils; (4) sandy soils; (5) loess, or silt rapidly pervious to water; (6) silt slowly pervious to water; (7) fine silts nearly impervious to water; (8) peaty or organic material. A tabular statement is here presented which shows the origin or mode of deposition and the areal distribution in Illinois of the several classes of soil:^ Table of soils of Illinois. Variety. Origin or iiiode of deposition. Areal distribution. Eesidnary Decay of the untlerly- i Driftless portion of the State wherever the loess ing rocks. as well as the glacial drift is absent. Glacial ; Mainly in the northeastern quarter of the State, where loess and silts are generally absent. The ] Shelbyville moriiine forms tlie southern liound- ary and chiefly the western boundary, but in niirtherii Illinois glacial clays form the soil on the lowau drift area between the Shelbyville moraine and the loess of the Mississippi Valley. (iravi-llv streams, lakes. the State, and along strciims leading away from tlic Shelbyville and later moraines. This variety of soil includes gravel knolls and ridges, over wash gravel jilaius, terraces, and beaches. ' This table wjis published by the writer in the Report of Illinois Board of World'.s I'air Com- missioners, 1895. SOILS OF ILLINOIS. Table of soils of Illinois — Con tinned. 791 "Variety, Sandy . Origin or mode of depositien. Areal distribution. Glacial drainage, streams, lakes, winds. Mainly in basins along the Kankakee, Green, and lower Illinois rivers ; old lake bottom and raised beaches near Chicago; also on bottom lands, and fringing' in many places the low blnflFs of streams, and locally developed on areas of gla- cial formations. Silts pervious to water In part by slowly flow- (chiefly the typical ing waters ; probably loess). in part by wind. Along the Mississippi, lower Illinois, lower Wa- bash, and lower Ohio rivers ; also between the Illinois and the Mississippi from the Green River Basin south to the latitude of Peoria, and in the basin of the Big Bureau Creek, in Bureau County. Silts slowly pervious to In part by slowly ilow- water. ing waters ; probably in part by wind. Mainly in west-central Illinois, west of a line con- necting Alton, Litchfield, Pana, Decatur, and Peoria; also on the eastern border of the Mis- sissippi Valley loess belt, in the northern part of the State. Silts nearly impervious to water. (Two kinds, namely, white clays and gumbo ) Nearly still waters; per- haps wind in part. White clays cover much of southern Illinois south of the Shelbyvilie moraine, as far west as the Mississippi loess, east to the Wabash loess and south to the Ohio River loess. Gumbo is found on soms bottom lands along the main rivers. Peatyand marly ' Vegetal accumulations and shell deposits. Locally over the greater part of the State wher- ever drainage is imperfect. Peat is rare south of the latitude of Springfield, but it abounds in the northeastern quarter of the State, in bogs. Marl deposits are less extensive than peat, but are fully as widespread. RBSIDTJAET SOILS. The residuary soils show variations which correspond in a rude way with variations in the structure of the rocks from which they are derived, there being in regions underlain by shale or limestone a more compact and adhesive soil than in sandstone regions. Each class of limestone has its own peculiar soil, and soils derived from shales range from stiif clay to a sandy material. A complete analysis of the nature of the differences dis- played by the several classes of residuary soils has not been made. With proper rotation of crops these soils are usually fertile, but otherwise they become exhausted sooner than soils formed on glacial drift. 792 THE ILLINOIS GLACIAL LOBE. BOWLDEK-CLAT SOILS. The soils formed on tlie bowlder clay are usually very productive, being composed of a varied rock material, a large percentage of which is in a sufficiently fine state of division to be available for plant food. Several mechanical analyses of this class of soil were made under the direction of Prof Milton Whitney, the results of which are given on a preceding page (p. 163). Professor Whitney has made the following statements regarding the bowlder-clay soils of Illinois:' The texture of the bowlder-clay lauds, as shown by mechanical analysis, corre- sponds very closely with the wheat and grass lands of Maryland, although none of the samples are so rich in clay as the limestone soils of that State. There is this to be considered, however, that there is a larger amount of volatile matter in the Illinois soils, showing that they contain probablj^ twice as much organic matter as the Mary- land soils. This would tend to make them more productive than soils otherwise similar in texture. As to the actual tests of the bowlder-clay soils it may be said tliat, in general, all classes of grains and fruits suitable to the latitude will flourish; especially where the surface is rolling or well drained. On the flat tracts corn and g-rass are exceptionally productive. GRAVELLY SOILS. Grravelly soils are varied in their method of deposition, occurring in lake beaches and along streams, in drift knolls and ridges, and beneath plains not now occupied by sti-eams. In the last-named situation the plains are usually so related to the drift ridges as to show that the_y were occupied bv glacial waters. The beaches have generally a poor soil, but the gravel terraces along streams, especially those of glacial age, have as a rule a capping of loam several feet thick, which renders them productive. The same is often true of gravelly knolls and ridges. On the whole the soils underlain by gravel possess more fertility than do sandy soils. This supe- riority is, however, due to the capping of loam which constitutes the soil, or, as in the drift knolls and ridges, to an admixture of clay or earthy material witli the surface portion of the gravel. The coarse fragments in the gravel can furnish but little sustenance to crops, although, by weathering, the stones may yield rich material to the soils and furnish a greater variety of. plant food than could be obtained from siliceous sand. Report (if lIliiHiis lioaid of World's Fair Coiiimissionors, p. 100. SOILS OF ILLINOIS. 793 SANDY SOILS. The sandy soils, though apparently much alike in structure, are varied in their methods of deposit. They occur in the beaches along the bor- ders of Lake Michigan, in the valley bottoms of the main streams, on the bluffs and along the borders of the streams which lead away from the newer drift district, in basins within the newer drift district, (as the Kankakee and Illinois- Vermilion), and to a limited extent in the moraines. There is also an extensive development of sand in northwestern Illinois, in the Green River Basin and the bordering districts, as far north as northern Whiteside County. Where the sand is of medium to coarse grade it is usually rather barren, but where fine, as in the eastern portion of the sandy belt bordering the Illinois in Tazewell and Mason counties, it is productive. Within the sand-covered districts there are more or less extensive tracts of wet, mucky land between sand ridges. This, where artificially di-ained, has often proA^ed very productiA^e. There are districts where the loess assumes a. sandy phase, but in these places the sand is very fine, so fine that individual grains can scarcely be detected by the eye, and the feitility Is about as great as in the typical loess. BLUFF LOESS SOILS. The very porous phase of the loess within the region under discussion is confined mainly to the borders of the Mississippi, Illinois, Ohio, and Wabash rivers, extending back usually but a few miles from the streams. It may therefore properly be called the "bluff loess." There is, however, a porous loess along the south border of the Green River Basin, and in general the loess between the Mississippi and Illinois rivers is more porous than on uplands to the west or east. In southern Illinois the loess becomes a compact white clay within a few miles back from the Mississippi, Ohio, and Wabash rivers, but in western Illinois it changes to the slowly per- vious silt which is more productive than the white clay. The very porous loess which borders the main streams will permit roots to penetrate readily to a great depth, there being observations of penetration to 25 or 30 feet. It is, however, usually of such a texture that water rises in it by capil- larity in dry seasons and adequately supplies the crops. The mechanical analyses of specimens of the bluff loess made under the direction of Professor Whitne)^ have been presented in tabular form in 794 THE ILLINOIS GLACIAL LOBE. connection with the discussion of the loess (p. KU). Concerning- these samples Professor Whitney remarks:^ , Tliey are lighter in texture than the best wheat lands of Maryland, although they have rather more organic matter to balance the low percentage of clay. They are more like our fruit and tobacco lands, although the higher percentage of volatile matters indicate that they are rather more retentive of moisture. The loess differs markedly from the agricultural lands of Maryland in the relative amounts of clay in the soil and subsoil. It is the rule of the Maryland agricultural lands to present a larger amount of clay in the sub- soil than in the soil, but in the loess the reverse appears to be the case, as the following table indicates: Percentage of clay in noil and subsoil of Illinois loess. Soil (per cent j Subsoil (per Locality. of clay). I cent of clay). Virginia City, No. 1 - : 15.34 Virginia City, No. 2 15-15 Carrollton - 23. 65 Eoclc Island , 12-08 Gladstone . 6.75 7.10 12.52 8.31 The bluff loess vields fair crops of all kinds, but is especially valuable for fruit, both orchard and small fruits. Its superiority in fertility over the white clav^ and finer silts seems due to the physical condition of porosity. Nothing has been found to indicate that it contains a better supply of plant food. ]\Ioreover, the fertility of the latter is made certain by the rich growth of such crops as will flourish in a compact soil. SILTS SLOWLY PERVIOUS TO WATER. The silts slowh- pervious to water embrace the rich black soil district ()f the western portion of Illinois. The southern boundary lies near a line connecting Alton, Litchtield, and Pana. The eastern boundary of the main district may be })laced at the border of the newer or \Msconsin drift. The northern boundary is near the south border of the Green River Basin, while the western lioundary is found in the loess that borders the Mississippi. Through this district there passes the belt of i)orous loess I Report of Illinois r.o.ird of Worlds F;iir Coinraissioners, p. 101. SOILS OF ILLINOIS. 795 which borders the Ilhnois, a belt several miles in width. Aside from this main district, there is considerable silt of this class between the Rock and Mississippi rivers, in northern Illinois, capping the earlier or Illinoiau drift sheet. On the newer (Wisconsin) drift, as stated above, silts slowly pervious to water cover large districts in central and eastern Illinois to a depth of several feet. In northeastern Illinois such a silt capping is not a common feature. Wherever silts of this class (iccur the vegetation is usually prairie grass, and there is a blackening of the soil hj humus to a depth of several inches, often 2 feet or more. This class of silts affords a highly productive soil, one which will yield fair returns even under most careless methods of farming. Corn and grass are the staple products, but other crops have a fair yield. FINE SILTS NEARLY IMPERVIOUS TO WATER. The fine silts nearly impervious to water are of two classes — white clay and "gumbo." The first class covers the uplands of much of southern Illinois. The second is common in portions of modern river valleys, remote from the current and subject to o^^erflow only in periods of extreme high water, and has great extent along the Illinois and Mississippi river bottoms. A less compact silt, found in river bottoms, is known as potato land. The white clay is a pale-colored deposit, scarcely at all blackened by humus. It covers the greater part of Illinois south from a line running- eastward from Litchfield, Illinois, to the Wabash Valley, near Terre Haute, Indiana. It also covers much of Clay, Vigo, and Sullivan counties, Indiana. It is so poorly drained that much of the water stands on the surface until removed by evaporation, while in seasons of drought scarcely enough wafer rises from below to supply the loss from evaporation. In the southeastern portion of Illinois and southwestern part of Indiana there is, however, a looser soil, less easily influenced either by excess or deficiency of rainfall. In those districts the surface is hilly and the white clay is much more eroded than in flat tracts. The drift is so thin, also, that the rock, in many places, comes sufficiently near the surface to have become uncovered by erosion and thus to give character to the soil. There are extensive districts in south-central Illinois with very flat sur- face where the white clay soil is underlain at a depth of a few inches hj a 796 THE ILLINOIS GLACIAL LOBE. ferruginous crust or ocliery clay, which is exceedingly refractory, g'iving very slow access to air or water. With this exception, however, the crust is either absent or is so low down that it does not seriously aflfect the soil. Aside from corn, which is liable to be injured by autunni droughts, the lead- ing crops of the State do fairly well. Wheat yields as well as anywhere in the State, wliile orchards and small fruits bring very })rofitable returns. The soil needs careful attention, but there is every indication that where properly cared for it will become as profitable for agriculture as the soils which now enjoy a better reputation. Concerning the analvses of the samples of white clay and also of the more porous upland loess (see \). 162) Professor Whitney remarks:^ Of the upland loess there are two types — those which are pervious to water and which are valuable agricultural lauds; those which are comj)act and almost imper- vious to water, locally known as white clays, which are so very retentive of moisture as to be always wet and of less agricultural value. The mechanical analysis shows that these two types of land are almost identical in texture, and that the white clays (1321, 1342, 1343, and 1345) have no more clay than the other samples of upland loess, which are considered very fertile lauds. The wetness of these white clay lands, therefore, is not due to the fact that they contain more clay, but it must be ascribed to some other cause. They contain no more organic matter, so that it can not be due to an excessive amount of this material. It must be due, therefore, to one of two causes — either that there is a hard pan or a layer of impervious clay underlying these lands which retards the descent of the water and prevents the excess of raiufall being carried down, or it may be due to a diiierence in the arrangement in the grains. Our laboratory experiments do not seem to indicate that there is any material difference in the arrangement of the grains in these two classes of soils, but this can only be determined with certainty by investigation of the soils in their natural position in the field. If the pervious character of the white clays is due to a difference in the arrange- ment of the grains, the lands ought to be underdraiued so that the excess o( water may be artificially removed, or the trouble may be greatly alleviated by liming the land, which will tend to make it more loamy and less retentive of moisture. The effect of kainit and of some of the jjhosphates would probably have a similar effect on the land if applied regularly for a number of years. If the soils are impervious because of a hard pan or a layer of impervious clay 3 or 4 feet below the surface, then fertilizers will do very little to correct the evil unless the lands are systematically luiderdrained. VBATY AND OBOANIC SOILS. The })eat>' and organic soils occur in basins or in poorly drained tracts where rank vegetation becomes submerged at certain seasons and is thus prevented from atmospheric decay. This class of soils is much more ' Keiiorli 1)1' Illinois Hoard of World's Fair Commissioners, pii. Ull-102 SOILS OF ILLINOIS. 797 abundant in the northern part of tlie region than the southern. Peat bogs occur, however, south of the center of the State of Illinois. Manv bogs are underlain by shell marl as well as by peat. The marl is seldom suflficieiatly pure or abundant to be used in the manufacture of lime. The marl beds are especially abundant on the south and east borders of Lake Michigan In many instances the bogs when drained, the peat })eing given time to ripen and become warm, yield large crops of potatoes and other garden truck. Wheat or other crops requiring mineral food in the ripening of tbeir grains can scarcely be expected to grow on such soil until it becomes charged with earthy material by natural or artificial processes. INDEX. ^5l. Page. Abingdon, 111., "wella at .* 678 Adair, 111., wrll at G86 Adams County, 111., altitude of 10 gf neral features of ll'^l]^ ridges in 58-59 section of well in 59 wells in 713-718 Adeline, 111., wells at 605 Adeline or Leaf Kiver esker, altitudes and course of. 76-78 composition of 77-78 .^olian loess dei»osits 183-184 Aftonian soil and weathered zone 20 Albertiin drift sheet 20,21,22 Albion, 111., well at 776 Alden, 111., well at 576 Alden, W. C., traces of Tolleston beach found by 448 Aledo, 111., wells at 622 Alexander, 111., wells at 723-724 Alexander County, 111., altitude of 11 Algoucj uin, III., wells at 578 Allejian, Mich., sections near 359,360 well at 359 Allegan County, Mich., moraine in 348-349 section of well in 402 th icliuess of drift in 355 wells in 362, 363, 304 Aljiha, 111., wells at 625 Alpine, 111. wells near 590 Alsey, 111., wells near 722 Altii, III., wells at and near 207, 674-675 Altaniont, III., wells at 753-754 Altitudes of drift surface and rock floor, table show- ing 9-11 of Bbelbyville moraine 194-195 Alton, 111 , glacial strife at 86-87 jaw of mastdduD found above 166 loess at 183 wells at 749 Alvin.lU .well at 700 Am boy. 111., wells at 610 Analyses, blufl' loess 161 bowlder clays 163 clays of Pleistocene age 411 Itiess 164 upland loess 162 Andover, 111., wells at 625 Andrews, Edmund, cited on bar north of Evanston . 445 cited on beacbes of Lake Chicago 418-419 cited on pockets of dry sand in lake tunnel 408 cited on the present beach of Lake Michigan . . . 453 estimates of extent of beacb of Lake Michigan, made by 454-456, 459 on the emergence of Lake Chicago 440 Anna, III., wells at 786 Page. Areola, 111., wells at and near 222,731 Argo, 111., well at 613 Arlington Heights, III., wells at 587 Artesian wslls in the Mississippi Valley 56 Artingstall, Samuel G-., cited on thickness of drift in Chicago , 406 drift-buried valley first noted by 583 Apple Creek, watershed of 522 Apple River, effect of glaciation upon 477 Ash Grove, drift sheets at 142 wells near GGl Ashkum, 111., wells near G57 Ashland, 111., section of drift beds in coal shaft; at.. 127 Ashley, George H., quoted on changes in Pigeon Creek drainage basin 98 Ashley, III., wells near 770 Ashton, 111., wells at 600 Astoria, III., wells at 688 Atlanta, 111. , section of well at . . . ^- - . 206 wells at 707-708 Augusta, III., wells at 683 Aurora, III., wells at 599 Au Sable Creek, watershed of 508 Austin, H. "W"., information furnished by 360 Ava, 111., wells at 780 A sis of upheaval 15 Kailey, Ind., section of well at 396 Bain, H. F., aid by 147, li8, 187 cited on loess deposition. 182 cited on sub-Aftoniau and Kansan ice sbeets 23 examination of Warsaw exposures 04-95 reference to 44.46 Baker, M. N., cited on sources of city water supply.. 557 Bald Mound 299 Bannister, H. M., cited on section of coal shaft at ■ Bloomington, 111 108 cited on southwestward outlet from Lake Michi- gan Basin 418 Barringtou, 111., wells at 581 Barry, 111., wells near 719 Bartlett, 111., well at 585 Base lines defined 4-6 Basseron Creek, course and drainage of 535 Bay Creek, chert near 62 course of 480-481 wells at 64 Baylis, 111., section of well north of 63 wells at ^ 720 Beaches, discussion of a possible second emergence of 446-447 Eeardstown, 111., altitude of rock bottonx at 500 wells at 711 799 800 INDEX. Bear Creuk, course of. 480 Bejitty's Mound, III., (veils at 747 Beecher, TU., wells near 754 Belleville, III., wells at 753 Belvidere, 111., fossils at 139 wcllsat 573-574 Benient, 111., wells at 220, 704 Benton Harlior.ilicb.. till riil;;o near ;{86-387 BevflD, J. S., inlbrmution fuinislied by 206 Berksville, 111., wells near 7GG Berrien County, Mich., altitude of 405 thickness of drift in 355 wells in 373,374 Bensonvill'e. 111., well at 592 Bethany, 111., depth of drift at 217 wells at 730' Beverlj', 111., section in well east of 00 wells at 718 Beyer, S. W., aid by 187 Biggsville, 111.. -wells at G80 Big Meadow Channel, discussion of 481-482 Big Muddy Kiver, wuterslied of 526-527 Big Raccoon Creek, source and watershed of 535-53G Big Sandy Creek, watershed of 522 BlackinioD, William, well section of 55 Black Lake, depth of 441 Black River, drainage basiu of 541 Black soil (Yarmouth), depth to, in wells near Den- mark, Iowa 54 Blatchley, W. S., information furnished hy 410 Blooraingdale, Ind , gravel-tilled valley near 1238-239 Bloouiingdale, Mich., well at 365 Bloomington, 111., buried soil at 265 drift sheet at 180 section of coal shaft at 108 structure of drift from Dekalb County to 267 valley-like depression southeast of 271 wcllaat 694-695 Bloomington morainic system, distribution 241-243 Gutwasliof -270-280 range in altitude of 245 relief of.. 244 structure of the drift of 266-269 thickness of the drift of 262-266 topography of 245-262 Blue Grass, Iowa, exposures at 46 "Blue Island," till ridge known as 382-384 Blue Island, III., wells at 590 BluOiMound, 111., well at 729 Blue Ridge, well at 234 Bluff Creek, amount of cutting along preglacial 488 preglacial course of 485 Bolton, 111 ., gravelly belt at 80 Bonrl County, 111., altitude of 11 general features uf 750 wells in 750-752 Bonus Township, 111., wells in 574 Bon Tas River, watershed of 531 Boone County, 111., altitude of 9 drift in 573 gravel knolls in 136 situation and area of 573 till ridge in 135 wellsin 573-575 Ilowlders along Chicago DrainatO Caual 420 at Keokuk, Iowa 95 I'uge. I IJowlders in Bioomingdalc Township, 111 357 1 in Lee County, Iowa 41 ' in Pike County, III 62 j in southwestern Indiana 66 I near Blue Island, 111 383-384 near Burton. Ill 59 near Fort Madison. Iowa .35-50 near Gilbert .Station, 111 302 near Morris, 111 325-326 near St. Louis, Mo 64 near Torkville, III 312 Bowman ville. 111., wells near 588 Briar Hill Station. 111., wells near 594 Braceville, 111., wells at G47 Bradley, F. H., cited on deposits in Vermilion County . 233 cited on name of Lake Kankakee 328 cited on section near Newport, Ind 236 Braidwood, 111., well at 650 Bridgmau, Mich., structure of drift at 399 thickness of drift at 392 Brighton, 111., wells at 743 Broadwell, 111. , wells at 708 Brooklyn, 111., wells at 787 Brown County, 111., altitude of 10 general features of 712-713 wells in 712-713 Brown Station. 111., well near 776 Bruilletts Creek, outwasb near head of 238 Buckley, 111. , wells at G61 Buda, 111., well at 628-629 Buell, Ira M., cited on deposits in Winnebago County 109-110 cited on exposures of stria? 87 reference to 88, 135. 141 well record collected by 570-572 work on till ridges in Winnebago and Boone counties 135 Buffalo Hart moraine, description of 74-76 dril"t in 75 Bunker Hill, 111., wells at 743 Bnreau County, 111., altitude of 9 bowlders in 269 buried soil in 264 drift structure in 267 general features of 626-027 ridge in 244 table of deep-wellsin 630-633 wells in 626-633 Bureau, Creek, topography near 246 topography of the drainage basin of 248-250 watershed of 512-513 Bureau Junction, 111., altitude of rock bottom at 500 well at 629 Buried rauck.*ce Muck, buried. Buried peat, «ce Peat, buried. Buried silt, Ace Silt, buried. Buried soil, nee Soil, buried. Burlington, 111., buried soil near 263-264 topography near 247-248 wells at 590 Burlington, Iowa, fossils found at 169 glacial strite at 85-86,105 loess at 156, 169, 183 Burr. Vu M., boring reported by 21(4 Burtnu, lU., drift strueture near 59 wells near 717 INDEX. 801 Page. Bushnell, 111., altitude near 482 drift near 26 old river valley near 481-482 wells at 685 Butler, IU..well3 at ....' 7-41 Byron, 111., wells at 606 C. Cache River, effect of glaciation on 528 Cairo, 111., preglacial drainage near 71 wells at 786 Cairo, Iowa, wells near 50 Caledonia, III., wells at 574 Calhoan County, 111., altitude of 11, 15 drift border in 35, 37 wells in 745-746 Call, R. E.; fossils identified by 168 Calumet or second beacb, character of 444-446 course of 442^44 Calumet River, drainage basin of 538-539 sand deposits near 409-410 section of ridge near 396 structure of drift along 393 Calvin, S., aid by 147, 148, 187 cited on the ice margin in Johnson County, Iowa. 150 cited on the lowan and Kansan sheet of north- eastern Iowa, McGee and 139 cited on the limits ot lowan drift 144 discovery of glacial striaa by 85 reference to 44, 46 Cambridge, 111., wells at 624-625 Campbell Hill, III., welU at 779 Campbell, J. T., information furnished by 412 Camp Point, III., wells at 716 Campton Township, topograph}-- south, of 299-300 Campus, III., wells at :... 667 Canton, 111., wells at 687 Carbondale, 111., wells at 780 Carbon Hill, III., wells at 647 Carlinville, 111., wells at 743 Carlyle, III., wells at 760 Carmi, 111., wells at 777 Carroll County, III., altitude of 9 general features of 148,611 wells in 611-613 Carroll Creek, gorge near 495 CarroUton, 111., wells at 745 Carthage, 111., filled valley near 57 wells at 682 Cary, 111., wells near 578 Casey, III., wells at 734 Cass County, 111., altitude of 10 general features of 710 wells in 710-711 Centralia, 111., wells at 760 Cedarville, 111., belt of gravelly drift near 81 gorge at 495 soil analysis at 161 Cerro Gordo, 111., drift at 220-221 wells at 704 Cerro Gordo moraine, character of the outwash of. . . 221-222 distribution of -. 218 structure of the drift in 219-221 topography of 218-219 Chadwick, 111., wells at 613 MON XXXVUI 51 Page. Chamberlin, T. C.,aid by 127,187,327 cited on artesian wells 555 cited on beaches of Lake Michigan 419,438 cited on classification of glacial deposits 185 cited on distribution of Illinois moraines 2, 3 cited on early Wisconsin drift sheet 191 cited on elevation of abandoned channel of the Mississippi 93 cited on erosion of Lake Michigan 457 cited on extent of Shelby ville drift sheet 192 cited on Leaf River or Adeline esker 76 cited on loess deposition 177, 178 cited on Marengo Ridge moraine 290 cited on names of glacial deposits 19, 20 cited on preglacial basin of Lake Michigan 7 cited on Shelby ville moraine 192 cited on structure of Champaign morainic sys- tem 232 cited on structure of Sheibyville moraine 198 cited on topography of Marengo Ridge moraine. 291 cited on Valparaiso morainic system 339 cited on Wisconsin clay beds 441 examination of Warsaw exposure 94-95 glacial work of 3^4 on invasions of the ice fields 23 on material in abandoned channel of the Mis- sissippi 93_94 on topography of Kettle moraine 303 quoted on drift in Kankakee Basin 317 quoted on sand areas in Kankakee Basin 328 reference to 421,543,547,551 report on boring at Lake Koshkonong 484 work on beaches 427 work on sand areas 333 Chamberlin, T.C., and Salisbury, R. D., cited on the drift border in southern Wisconsin 43^4 Champaign, III., sections at 234 topography near 227 wells at 702 Champaign County, HI., altitude of 10 general features of 701 limestone in 232 till plain in 239 wells in 701-703 Champaign morainic system, distribution of 223-225 range in altitude of 226 relief of 225-226 topography of 227-231 Chapin, 111., wells at 723 Charles Mound, altitude of 8, 16 Charleston, III., wells at 201, 735 Chatsworth-Cayuga Ridge, topography near 259-260 Chats worth. III., wells at 666-667 Chebanse, HI., wells near 657 Chemung, 111., wells near 576 Chenoa, 111., wells at 693 Chesterton, Ind., analysis of clay at 411 section of woll near 396 Chicago, altitude of plain west and south of 404 structure of drift at Fullerton avenue in 409 structure of drift at Hyde Park Township in... 409 stri^ on Stony Island in 4i5_4i6 thickness of drift in 406 Chicago Drainage Canal, bowlders along 426 structure of the drift along 407 Chicago Heights, III ., wells at 591 802 I]S"DEX. Page. Chicago Ontlet, maps of 420-421 meaning of name 420 -width of 424 Chicago River, beacn on west side of 430 drainage basin of 538 Chillicothe, terrace at 275-276 Christian County, 111., altitnde of 10 analysis of soil from 161 general features of 725-726 wells in 725-727 Cissna Park, 111., well at 661 Cisne. 111., wells near 775 Clark Conn ty, HI., altitude of 10 general features of 73^734 wells in 733-734 Clay County. 111., altitude of 11 general features of 757-758 wells in 757-758 Clayton, 111., drift sheets in the vicinity of '142 wells at 660-661, 705-706, 716 Clinton, IlL, section of gas well at 205 thickness of drift at 205 Clinton. Iowa, glacial deposits at 147-148 preglacial course of the Mississippi Kiver below. 466-467 Clinton County, 111., altitude of 11 general features of 760 table of wells in 761 wells in 760-761 Clinton County, Iowa, belt of drift in 144-145 Clinton Township 111., section of knoll in 287 Clyde Township, sandy belt in 149 Coal City, 111., wells at 647 Coal Creek, gravel along 239 Coal Measures district, altitude and drainage of 17 Coatsburg, HI., composition of ridge leading from.,. 61-62 section in a boring for coal east of 02 wells at 715-716 Coles County, 111., altitude of 10 general features of 734-735 wells in 217,734-730 Coleman, A. P., cited on Toronto formation 189 Colfax, 111., wells at 694 Collett, John, reference to - 88 Cohima, Mich ., well at 369 Cols 100,101,102 Columbia, 111., exposures at 65 wellsat 765-766 Columbia Station. Mich., section near 365 Columbus City. Iowa, well at 50 Columbus Junction, Iowa, abandoned channel near. 90, 91, 93 wells at 34,50 Conaro, James, well section of. 55 Concord, 111., wells at 777 Cooley, L. E., cited on the Chicago outlet 419,425 cited on variation in the bed of the upper Illi- nois Kiver 502 cited on the watershed of Des Plaincs liiver 503 the drainage area of tho Illinois River estimated hy 497 filling, estimated by -124 information furnished by 384,422 study of the movement of water iu Lake Michi- gan by 455-456 Cool Spring jmstoflico. ridge near 72 Cook CfMiiity, III., altitude of 9 situalion ami general ff-aturoa of 581-583 Page. Cook County, 111., wells in 581-591 Coon Creek, well near 574 Cooper, HI., wells at 692 Copperas Creek, watershed of 516 Coppock, Iowa, old channel of the Mississippi Eiver at 92.93 Cordilleran, ice field, extent of 22 Cornell, 111., wells at 666 Cortland, topography near 248 Cottonwood, HI., wells near 784 Conlterville, 111., wells at 769 Covel Creek, watershed of 510-511 Covel Ridge, description of 288-289 Covert, wells near 400-401 Covert Ridge, altitade of 391 beach near 433 bowlders on 393-394 course or 388-3S9 sand ridge on 433 .«!ection of 394 topography of 380-390 wave action at 436 wells and borings on , 400,401.402,403 Cowden.IU .wells at 739 Crab Orchard Creek, watershed of 527 Crawfish Flats, 111., wells at 776 Crawford County, HI., altitude of 11 general features of 755 wells in 755-756 Crescent, 111., wells near 659 Crescent City, drift sheets at 142 Creslon, 111., wells at 608 Crooked Creek, watershed of 520 Cropsey Ridge, topography near 253-259 Crossville, HI., wells near 777 Crystal Lake, 111 ., wells at 577-578 Cullom. 111., wells at 607 Cumberland County, 111., altitude of 10 exposures of Sangamon soil in 127 general features of 736-737 .soil analysis 162 wells in 736-7.t7 Gumming, Thomas, information, furnished by 647 Curran, HI., wells at 725 Curtis, G. C, and J. E. "WoodwortU cited on Nan- tucket as a mttrainal island 272 Curtis, L. R., acknowledgments to 641 T>. Dakota, Stephenson County, transported rock ledges near 83 Dall, W. K., examination of fossils by 115 fossils identified by 169-170 Dallas, III., wells at 082 Dalton. 111., wells at 730 Dalt on City, wells at 217 Danforth, III., wells at 657-658 Dan vers, III., wells at 695 Danville, III., well at 699 Danville Junction. HI., well at 699 Darling, G. "W., statement by 071 Davenport, Iowa, fossils found at 168, 17^ section in railway cutting near 128 section of drift at 45 Dnvie.s8 County. III., drift border iu 69 Davis, W. M., cited on the Chicago Outlet 420 INDEX. 803 Page. Davia Juuction, 111., wells at 607 Dawsou, George M., cited on centers of ice dispersion . 22 cited on Cordilleran ice field 22 Dean, George, actnowledgments to 627 Deans Corners, 111., well at 581 »ecatur, 111. , sections of drift at 203-204 wells at 729 Decorra, 111., wells near 680 Deer Creek, gravel deposits in 274 Deerfield, till ridge near 381 Deerfiold post-office, 111., well at 602 Deep Kiver, exposures of clay near 410 Deep Kiver Basin, old bay near 431 Dekalb, 111., wells at 602-603 Dekalb County, 111., altitude of 9 bowlders in 268 buried soil in 264 general features of 599-600 structure of drift from Bloomington to 267-268 wells in 599-604 Delavan, 111., wells at 691 Denmark, Iowa, section in wells near 54, 55 Densmore, J. E. , wells of 63, 64 Deselm poat-ofQce, 111., wells at 654 Des Moines County, Iowa, wells in 50 Des Plaines Kiver, beacb on west side of 430 deposits along 376-377 erosion in valley of 422-423 strisB in valley of 415 terraces on 321-322 till ridge near 380 topography along 384 topography near 345 watershed ofthe 503-505 Des Plaines Village, 111., wells at 587 Detroit, Dl., wells near 720 "Devil's Backbone," description of 286-287 Devonian shale 14 Dewey, F. "W., information furnished by . 649 Dewitt County, 111., altitude of 10 general features of 704-705 wells in 704-707 Dickey, 111., wells at 654 Dickerson, 111., well near 702 Diona, 111., wells at 736 Displacement of the Mississippi, temporary 89-97 Dixon, 111., exposures of lowan till in 138 wells at 609 Dowagiac Kiver, course of 540 Downers Grove, HI., wells near 593 Donovan, 111., drift sheets at 143 wells near 659 Dooley, P. T., information furnished by 580 Douglas County, 111., altitude of 10 general features of 731 wells in 236, 731 Drainage, changes in southwestern Indiana in 97-104 from the ice sheet in the Mississippi "Valley 71 influence of the drift upon 460-461 Drentbe, wells at 403 Drift, altitude of 9-11 average thickness of 544-546 changes in central Illinois in 28 methods of estimating thickness of 543 relation of the Illinoian to the lowan 24-25 outline of and intervals between sheets of 20-21 Page. 1-2 33-34 27-28 8-9, 27 26-27 64 37-38 34-38 43^4 40-63 3&-40 183, 188 9-11 12 73, 135 35,69 98, 102 160, 164 733 756 757 595 -208, 674 Drift, previous investigations of sections of the Illinoian structure of thickness of topography of Drift border, character of east of the Dlinois Kiver. . determination of the distribution of the structure of, in southern "Wisconsin structure of, in southeastern Iowa topographic character of the Driftless area, features of 34, 144, 152. 153, 154. Drift surface, Illinois, table of altitudes of Michigan, Indiana, andlowa, average altitudeof. Drumlina, occurrence of Dubois County, Ind., drift border in changes in drainage in Dubuq^ue, Iowa, analyses of soil at Dudley, 111., wells at Duncanville, 111., wells near Dundas, HI., wells at Dundee, 111., wells at Dunlap, wells near 207- Dunning, 111., well near Dupage County, 111., altitude of area and general features of wells in Dupage Kiver, deposits on watershed of Duquoin, III., wells near Dustin post-office, 111., wells at D wight. 111., wells at Dyer, Ind., beach near section of beach at 439 Eagle Lake, welle near 364 Earlville, 111., wells near 636 Early Wisconsin drift 20 East Carondelet, 111., wells at 762 East Crow Creek, watershed of 513 East DubucLue, Iowa, soil analyses at 161 well at 565 East Lynn, 111., wells at 699 East St. Louis, Dl ., analyses of gumbo at 160, 163 drift below 65 wells at 762 Eden Station, 111., wells near 769 Edgar County, 111., altitude of 10 general features of 732 outwash in northern 238 wells in 217, 732-733 Edgewood, 111., wells near 754 Edwards County, 111., altitude of 11 general features of 775 wells in 775-776 Edwards Kiver, description of course of 478-479 well near 622 Edwardsville, 111., wells at 749 Eel Kiver, strise along 414-415 Effingham, lU., wells near 754 Effingham County, 111., altitude of li general features of 753 wells in 753-754 Eldorado, 111., wells at 782 Elida, 111., wells at 572-573 591 591-594 376 505 771 601 665 431 804 INDEX. Elgin, m., Trells at and near 585, Elkhart, III., wells at Elkliart Mound, description of Elkhorn Creek Basin 18,79, Elkville, nl., wells at EUery, 111., wells near Elmhurst, 111., wells at Elm wood, HI., wells near Elpasn, lU., wells at ElvastoD, m., wells at Elwood, Iowa, drift border near Embarras Eiver, course and watershed of outwashin valley of --■ 209- wells along Emden, 111., well at English, J. G., well section reported by English Prairie post-oifice, wells at Eolian loess dposits Erie, 111., wells near Ester, Haaelhnrst Garden Plain Leaf Kiver or Adeline Esker ridges of northwestern Illinois Esker system, Pecatouica Eubanks, 111., drift border near Eugene. Ind., section of well near Eureka, 111., wells at Evanston, 111., sections of beach at shells found on beach at structure of the bar near well at Page. 595-596 709 75 132, 155 780 775 592 675 671 682 145 534-535 -210, 238 755 708 699 577 183-184 617-618 78 79-80 76-78 76-82 80-81 58 236 671 450, 451 451 445 587-588 Fairbury, III., wells at Fairfield, 111., wells at Fairgrange, 111., wells at Fair Haven, 111., well at Fairmount, 111., wells at Farm Creek, gravel deposits on watershed of Farmer City, 111., section in boring for coal at wells at Farmington, 111., wells at and near 686 Farm Eidge, topography near Fayette County, 111., altitude of general features of wells in Fecnville. Mich., wells at Ferdinand, Ind., col near Ferruginous conglomerate Fidelity. 111., wells at : Fieldon. Ill ., well at Findlay, 111., wells at Fisher. A. J., infoi-mation foruished by Filbian, 111., wells at Flint River, course of Flora, 111., wells at Florentia lorniation Foggy, Andrew, well section of Ford County, 111., altitude of general fi-atures of table of deep wells in topography of wells in Forest. 111. , wells at Forester. John, iiifomintion furnished by 666 775 735 613 700 212. 274 514 215-216 705 -687, 736 2G0-2G1 11 752 752-753 403 101-102 107, 109 747 747 740 629 700 479 758 167 53 10 662 603-664 254-255 662-664 666 772 Page. Forreston, 111., classification of pebbles near 78 wells at 605 Fort Branch, Ind.. ridged belt near 67-68 Fort Madison, Iowa, drift thickness near 52, 56, 71, 156 Fossils, distribution of 165 names in Pilsbry and Johnson's check list 168-171 list of loess fossils 168-174 Fosterburg, 111., wells at 749 Fountain Bluflf, 111., deflection of Mississippi River at 474 Fountain County, Ind., wells in 237 Fowler, 111., wells at 715 Fowler and Liberty, HI., drift between 60-61 section in well between - - 61 Fox Kiver, altitude east of 305-306 altitude west of 297-298 belt of gravel along 313 character of drainage of 498 correlations of the morainic belt west of 302-304 morainic belt east of 304-305 outwash on 375-376 strife along — 415 structure of drift east of 306-307 structure of drift west of 300-302 thickness of drift along 283 thickness of drift east of 306 topography west of 298-299 watershed of 509-510 Francisco, Ind., col near 101-102 Franklin, 111., wells at 724 Franklin County, 111. , altitude of 11 general features of — 778 wells in 778 Franklin Grove, 111., wells at 609 Freeburg, lU., wells near 761 Freeport, 111., fossils found at 169-170 gorge near 494 section showing "Silveria formation" near 112 "Silveria formation" near 113 wellat 568 1 Friendsville, 111., wells at 776 : FuUersburg, HI., wells at 592 Fulton, 111., deflection of the Mississippi Kiver at. . . 462 wellsat 615 Fulton County, 111., drift ridge of 76 general features of 686 wells in 686-688 Fultz, F. M., discovery of glacial strise by 85 Funk, Lafayette, information furnished by 695 Funks Grove, 111., wells at 695 Furse Creek, deflection by glacial boundary 102 &. Gallatin County, III., general features of 783 wells in 783-784 Galesburg, 111., wellsat 676-677 Galena, 111., wells at Galewood, 111., well near Galien River, drainage basin of Galva, 111., exposure at wells at Gannett, Henry, cited on magnetic variation cited on mean elevation of Illinois 7 Garden City, Ind., auillysis of clay at 411 Garden Plain esker ' ^-80 Garden Plain, III., wella at 015-816 Gardner. III., wellsat ^~ 565 588 539 130 624 412 INDEX. 805 Page. Gaa wells in Illinois 557 Geikie, James, cited on naming of glacial deposits. . 19 Genesee, 111., well at 623-624 Geneva, 111., wells at 597-598 Genoa, 111., wells at 601 Gibson, 111., wells at 663 Gibson County, Ind., change of drainage in 97,98 drift border in 35, 39, 40 Giflford, 111., wellsnear 702 Gilbert, G. K., cited on uplift of Niagara outlet 453 reference to 84 Gilman, 111., drift sheets at 142 wells at 658 Gilmer, 111., well at 581 Girard, 111., wells at 743 Glacial boundary 34-37, 144 Glacial deposits, Chamberlin on names of 19,20 geographic names applied to 19-20 in St. Louis County, Mo 64r-6o near Flummer's Creek 69-70 Glacial history, outline of 20-21 Glacial striae 84-88, 105, 140-141 Glacial waters, extent on the borders of the Missis- sippi River 181 Gladstone, 111., soil analysis at 161 Glasgow, 111., wells near 722, 766 Glavin, , elevations determined by. - - 433 measurements of erosion of Lake Michigan fur- nished by 458 Gleenwood Beach, description of 428-442 Glen wood. 111., wells near 590 Gobies, Mich., altitude near 350 moraine near, description of 350 well near 366 Godfrey, III., wells at 749 Golconda. 111., wells at 787 Golden Gate Station, 111., wells near 775 Good Hope, 111., well at 686 Gooding, "Williarn, report upon the survey of the Illinois River, mentioned 418 Goose Lake Channel 145 Gordon, C. H., cited on preglacial channel of the Mississippi River 469 cited on the bowlder bed at Keokuk 95 cited on "Yellow banks" section 94 Gossert, S.D., information furnished by 616 Grand Detour. 111., wells at 606 Grand Fork, 111., wells at e 750 Grand Junction, Mich., altitude of rock surface near 350 moraine near 349 well at 364 Grand Ridge, topography near 260-261 Grand Tower, 111., barrier ridge near 14 Gray ville, 111., wells at 777 Great Bear Lake, topography near 348 wells near 355 Greene County, 111., altitude of n change of drainage in 102, 103 general features of 744 wells in 744-755 Greene County, Ind., drift border in 36 striae in 37 Greenfield, 1 11., wells at 745 Greenleaf, J.L., cited on descent in the lower rapids of the Mississippi River 470 Page. Greenleaf, J. L., cited on the area of the watersheds of the Illinois River 496-497 estimate of discharge through Rock River "Val- ley 489 Green River, age of the channel of 493 course of 492-493 Green River Basin, erosion in 492 gravel plain at head of 277 loess in 793 sand deposits near 277 Greenup, 111., wells at 737 Green Valley Village, 111., wells at 692 Greenville, 111., soil analysis at ]62 wells at 75]^ Griggsville, 111., wells at and near 63, 720 Griswold, 111., wells at 667 Grundy County, HI., altitude of 10 genei al features of 645-646 ■^ellsin 645-648 Gumbo, extent of 28-33 origin of 29-30 time relations of 30 Hainesville, HI., wells at 531 Hallsville, 111., wells at 706 Hamilton , HI., drift above 53 section in well south of 57 strisB near J05 wells at 683 Hamilton County, 111., altitude of n general features of 777-778 wells in 777-778 Hammond, Ind., thickness of drift at 392 Hampshire, 111., wells near 594 Hancock Conn ty, 111., altitude of 10 general features of 681-682 table of wells in 683-684 ■^ellsin 681-684 Hansel, Charles, information furnished by 204 Hardin County, HI., altitude of n Harman, J. H., information furnished by 675 Harrington, Mark W., cited on the currents of Lake Michigan 455 Harrison Harlan 's, well at 2O8 Harristown, III., wells near 728 Hartsbnrg, 111., well at 703 Harvard. 111., well at 576 Harvey, III., well at 590 Haubstadt, wells near 67 Havana, 111,, wells at 539 Hazelhurst. 111., wells at 605-606 Hazelhurst esker, description of 73 drift ct 79 knolls near 79 Hecker, 111., wells near 766 Henderson County, 111., altitude of 10 general features of 679 wells in 679-681 Henderson River, course of 479 Hennepin, 111., well at 634 Henry, 111., wells at 669 Henry County, 111., altitude of 9 general features of 623 table of wells in ' 625 "wellsin 623-625 806 INDEX. Page. Hershey, Oscar H., aid by 147-148,567 cited on basin-like expansion of the Talley of Pecatonica River 18 cited on Cedarville gorge 495 cited on Freeport fossils 167 cited on Leaf River or Adeline esker 76,77 cited on rock gorges of northwestern Illinois 491, 494 cited on silts in northwestern Illinois Ill cited on the physiographic development of the Upper Mississippi Valley 461,462 cited on transported rock ledges 82, 84 cited on water-bedded silt 181-182 exposures of lowan drift noted by 138 fossils collected by 169-170 on eskers in Stephenson and Ogle counties 80,82 reference to 552, 568 ridge observed by 136 ■work on ■western border of the lowan drift sheet 131 Heyworth, HI., section of well near 215 wells at 695-696 Hickory Creek, course of 540 watershed of 505, 535 Highland, HI., ridge from Pocahontas to 72-73 wells at 750 Highland Park, 111., wells at 580 Hill, A., well section of 63 Hillsboro, 111., coal boring at 741 Hinckley, HI., wells at 604 Hinde, George J., cited on fossiliferons beds near Toronto 189 Hinsdale, HI., wells at 592-593 Hobart,Ind., analysis of clay at 411 t bickness of drift at 392 Hoffman's, F. N., well at 587 Hagar, ilich., section near 395 Hog Run, watershed of 508-509 HoUandsville, HI., wells at 749 Homer, HI., wells near 703 Hoopeston. HI., wells at 698-699 Hopedale, HI., well at 214,692 Houston, HI., wells near 768-769 Hoyleton, 111., wells near 770 Humboldt, wells near 221 Hutchinson's Lake, wells near 402 I- Ice dispersion, centers of 21-22 Ice invasion, efl«ct of the Hlinoian, on the outer bor- der d rainage 89-105 Ice sheet, direction of retreat of 427-428 in Mississippi Talley, drainage of 71 Ideal, 111., wells near 613 Hlinois, altitudes in 7-12 area of 12 barrier ridge in southern 14 changes in drift in central 28 bowlders in eastern 198 composite mor;iinic belt of northern 290-307 distribution of drift in, by depths 548 drift in southern 65 elevated liraestono belt in 16 elevation of glacial lobe of 179 esker ridges of northwestern 76-82 extent of gumbo in 28-33 Page. Illinois, gravelly soils in 792-793 knolls in the vicinity of drift border in southern. 39 loess in northern 154 measurements of rock gorges in northwestern. . 494 mounds of ^Niagara limestone in 16 paha in 134-135 residuary soils in 791 rock gorges of northwestern 493-496 rock gorges in western 496 sections of drift in 33-34 silt deposit insonthem 116 silt in western 794 soils in (table) 790-791 sources of soil material in 788 strife in northeastern 415 structure of drift in 27-28 thickness of drift in 27 till in 28 till in Ohio Valley in 65-66 topographic character of the drift border in 38-40 topography of drift in 26-27 wells in unglaciated counties of 784-787 white clay in southern 795 Hlinois and Iowa ice lobes, relation of the 151-153 Hlinois River, altitudes near 15 altitudes of rock floor and present lower 501 composition of ridge between Mississippi River and 60-61 course of upper 501-502 deposits along 498 deposits at the head of the 423 depression north from Beardstown, in valley of. 500-501 divisions of valley of 498-499 drainage area of the tributaries of 497 drift border east of 64 drift structure along 284 erosion belowthe Morris Basin in 423 extent of the watershed 496-497 former lake at the bead of 337 gravel deposits in the valley of 275, 276 loess in valley of 156 preglacial and postglacial condition of 422 Shelby ville moraine east of 214 structure of drift west of 213-218 topography between Mackinaw River and 251-252 topography west of 250-251, 280-281 variations in the bed of Upper 502 wells west of 207 Hliopolis, 111." wells at 725 Indian Creek, sand ridge near 329-330 watershed of 521 Indiana, altitudes in 7.405 change in drainage in southwestern 97-104 drift in south western 66-67 elevated tract of conglomerate sandstone in 16-17 "bill country" of 16 strife in northwestern 414 till in southwestern 66-67 western, thickness of Shelby ville drift in 199-200 Indianola, 111., wells at 700 lola. 111., wells near 758 Iowa, altitudo of 7 structure of drift border in soulbeaatern 40-43 Iowa ice lobes, relation of the Illinois and 151-153 Iowa River, section of well in valley of 50 lowan drift sheet of the Illinois lobe, distribution of. 131-134 INDEX. 807 lowan drift sheet, probable extent of tbe Iowa por- tion of tho probable extent of Wisconsin sheet beneath soil and peat between Wisconsin sheet and structure of thickuess of topography of lowan loess, character and occurrence of distribution of raineraloglcal constitution of size of the grain of. structure of variations in thickness of variations in structure of lowan outline compared with succeeding and pre- cedi ng glaciations Ipava, 111., well at Irene, 111., wells in Iroquois, 111., well at Iroquois Basin, outwash in sand near, coarseness of Iroquois County, 111., altitude of drift sheets in general features of soil horizons in topography in topography of moraine in wells in Iroquois moraine sand deposits, interpretation of... Iroquois Kiver, outwash along basin of sand area near watershed of Irving, R. D., cited, on preglacial basin of Lake Michigan Isabel, 111., wells near Itasca, 111., wells near Page. 144-153 141-144 185-186 137-140 136-137 134-136 153-165 153-155 159 158-159 156-164 155-156 157 188 688 575 659 323 333-334 11 142-143 654^656 265-266 282 258 654 336-337 314 331 507-508 7 733 592 Jackson County, 111., altitude of 11 general features of 778-779 atrins in 87 wells in 778-780 Jackson and Randolph counties. 111., ridge in 73-74 Jackson and Williamson counties, 111., strise in 87 wells in 780-781 Jackson Creek, watershed of 505 Jacksonville, lU., wells at 723 JanesviUe, Wis., preglacial valley near 483-484 Jasper County, 111., altitude of 11 general features of 754 wells in 754-755 Jefferson County, 111., altitude of 11 general features of 773-774 wells in 773-774 Jenkins, O. P., information furnished by 412 Jersey County, 111., general features of 746-747 wells in 746-747 Jersey ville, 111., wells at 747 Jo Daviess County, 111., altitude of 9 area of 564 wells in 564-567 Johnson Countj'", 111., altitude of 11 Johnson Creek, 111., exposure at 129-130 Johufion's Mound 299 Joliet, 111., strige at 415 wells at 649-650 Joliet Mount, 111., section of 377 Joy. 111., well near 623 Kalamazoo River, depth of 441 drainage basin of 541 moraine along, description of 349 sand plains near 436-437 wells in valley of 359 Kane County, 111., altitude of 9 area and general features of 594 bowlders in 268 wells in 594-599 Kane and Kendall counties, means of deposition of gravelly plain in 323-324 Kaneville, 111., wells near 598-599 Kaneville esker, description of 284-286 Kankakee Ilk, wells at 653 Kankakee Basin, character of 498 Kankakee County, 111., altitude of 10 general features of 653 wells in 653-654 Kankakee Lake, interpretations of the sand deposits known as 334-338 Kankakee River, bowlders along 325-326 deposits along 378-379 descent of the 506-507 drainage basin of 505-507 sand deposits along 322-323 sand near, thickness of 333 topography near 332-333,347 till plain along valley of 324-325 Kansan drift sheet, erosion of the 121-123 Kansan till, extent of 105 Kansas, 111., wells at 217,733 Kansas City, Mo., analyses of loess at (table) 164 Kaskaskia Basin, origin of the ridges of the 73-74 ridged drift of the 71-74 topography of ridges in 72-73 Kaskaskia River, bluff of, section of 739 course and watershed of 523-524 drift in valley of 202-203 outwash in valley of 210, 238 Keithsburg, 111., wells at 622 Kendall County, 111 ., altitude of 10 general features of 643 table of wells along the Marseilles moraine in. . . 645 wells in 643-645 Kendall and Kane counties, III., gravel plain in, three means of deposition of 323-324 Kenney, 111., well at 706 Keokuk, Iowa, bowlder bed at 95-96 "Yellow banks," section near 94 Kee watin ice sheet, limits of 22 Kent Creek, gorge on 492 Kent, 111., well at 568 Kewanee, III., wells at 624 Kickapoo Creek, gravel filling along 271-272 outwash in valley of 276 terraces of gravel along 212 watershed of 513-514, 519 Killbuck Creek, sand and gravel deposits along 278 Kimball, 111., wells near 755 Kingsley, Robert, information furnished by 372 Kings Station, 111., wells near '. 607 Kingston, 111., wells at 60 808 INDEX. Page. Einmnndy, HI., wells at "59 Kisb wankee River, effect of glaciation on 485 baried soil in Tallev of 293 gravel plain in valley of 294 wells along 600 Kite River, coorse of iS6 preglacial excavation in valley of 4S9 preglacial excavation sooth of 489 sand and gravel deposits along 278 Kite and Leaf preglacial rivers, excavation on di- vide between - 489 Knolls in Logan Coonty, HI 75 in the vicinity of drift border in sontbem niinois 39 near Hazelhurst esfeer 79 Knowlton. F. H., on plant remains 31 Knox County. HI., altitude of 10 general features of.. 676 views in cuttings along Santa Fe Railway in eastern 126 wells in 676-678 Knoxville, HI., wells at 677 Labradorian ice field, limits of 23 Lacon, HI., wells at 669 Lagrange, HI., gravel pit between Salt Creek and. . . 438 wells at - 589 Laharpe.Hl., wells at ^ 682 Lahogue, HI., wells at 658 Lake Chicago, discussion of the emergence of the beaches of 442 elevation of 435 elevation of upper beach of 437-43S outlets of, at the time third beach was forming. . 452 Lake County. HI., altitude of 10 general character of 579 wells in 579-581 Late Forest, 111., weUs at 580 Lake Hennepin 152,153 Lake Michigan, bulk of the beach of 454 depths of lakes tribniarj- to 441 drainage basin of 538 erosion of the shore of 456-459 estimated age of 459 evidence of emergence along east shore of 441 marl beds along 797 present beach of 453-459 present movement of the border of 453-454 profiles across 12-13 section of bluff of 395 structure of drift around the head of 356 water movements in 455-456 Lake Richland 103 Lake St. Clair, deposits along the head of. 425 Lake Znrich. HI., wells near 531 Lakeside Station, Mich., beach near 433 Lamoille, 111., wells at 627 Lanark, dl.. wells at 612 "Lanes Island," HI., wells on ^0 Lasalle, HI., wells at 637 Xasalle County. 111., altitade of 10 buried soil in 264 general features of 635-636 table of wells al on glfarseillea moraine in eastern . 6:t9-.641 table of wclU in. outside of Marseilles moraine. . 641-647 wells in 635-^2 Page. Lawndale, HI, wells at 708 Lawrence. Mich., generalized section of wells at 371 Lawrence Cotmty, HI., altitude of 11 general features of 756 wells in 756 Lawrenceville, 111., wells at 756 Leaf River, course of 4fi5 cuttingalong preglacial valley of 486 excavation on the divide between the preglacial Kite Riverand... 459 preglacial excavation along soath tributary of 489 Leaf River or Adeline esker, description of 76-78 Lebanon, HI., wells at 763 Leclaire. deflection of the Mississippi Rivw at 463-464 drift at 464 Lee County. HL, altitude of 9 bowlders in 268 buried soil in 264 general features of 608 table of deep wells in eastern and southern 610 wells in 608-611 Lee County, Iowa, drift in 52 old channel of the Mississippi River in 93-94 red jaspery in 24 Lee Station, well at 364 Lementon, III., coal boring at 764 Lemmon, FUa. acknowledgments to 627 Lemont, glaciated surface near 416-417 Lfpus siflraticug 42 Lena, HI., well at '. 568 Lema, wells at 202.736 Leroy.Hl. wells at 215.695 Letts. Iowa, wells near 49 Leverett. Frank, cited on beaches of Lake Michigan . 419 cited on glacial history 21 cited on interglacial interval. ..'. 41 cited on low altitude at St. Paul 475 cited on rock borings at Princeton 500 cited ou the deflection of Big Cedar Creek 90 cited on the lower rapids of the Mississippi River 470 cited on the relation between the Hlinoian till sheet and the lowan loess 25 cited on soil horizon in eastern Illinois 186 cited on wells of northern Indiana 359 fossils collected by 169 quoted on the naming of "Lake Chicago" 427 reference to 24.88,125 Lewistown. HI., wells at 688 Lexington, gravel deposits at 279 Liberty. 111., drift between Fowler and GO-61 section in well between Fowler and 61 wells at 716-717 Lily Lake, HI., section of boring near 294 Limestone mounds 16 Limestone ridges 14-16 Lincoln. 111., well at 708 Lindcrwood. HI., wells near 607 Lisbon, HI., wells near 644-645 Lis'.e. HI., wells near 593 Litchfield, 111., wells at 741 Uttle Rock esker description of 286-288 Little VemiilioD River, watershed of 519 Little Wabash River, course and watershed of 530-531 section of bluff of 758 INDEX. 809 Page. Livingston County, 111., altitude of 10 general features of 664^665 table of wells in 667-668 wellaiu 664-668 Lobes, relation of the Illinois and loAva ioL' 151-153 Lockport limestone, mounds of 16 Loda, 111., -wells at 662 Loess, PEolian 183-184 analyses of 158-164 discussion of 32 leached, beneath the Wisconsin drift 187-188 mode of deposition of 176-184 Ustof fossils of the 168-17'i relation of blaff to upland 182-183 relation of gummy clay to 31 Logan County, 111., altitude of 10 general features of 707 knolls in 75 wells in 707-709 Lombard, 111., wells at 593 Long Grove, Iowa, bowlders near 147-148 Logootee, Ind., drift border at 36, 69 Lost Creek, effect of glaciation on 480 Louisville, 111., well at 758 Loveless, James, well section of 61 Lowder, 111., wells near 725 Ludlow, 111., wells near 702 Lynn Center, 111., wells near 625 Mackinaw, 111., wells at 692 Mackinaw Kiver, gravel deposit on 273 terrace on 211-212 terrace in valley of 273-274 topography between Illinois Kiver and 251-252 topography east of 252-254 topography near 282 watershed of 5] 4 Macomb, 111., well at 685-686 Macon, 111., drift at 203 well at 729 Macon County, 111., altitude of 10 general features of 727 wells in 727-729 Macoupin County, general features of 742 wells in 742-744 Macoupin Creek, watershed of 522 Madison County, 111., altitude of 10 general features of 748-749 till in 64 wells in 748-750 Mahomet, 111., outwash at 237 wells and exposures at and near 216-217, 703 Manchester, 111., wells near 722 Manistee, Mich., drift at 13 Mansfield, 111. , well at 704 Manvaise Terre Creek, watershed of 521-522 Marcy, Oliver, section of beach taken by 450 shells collected by 451 Marengo, HI., wells at 577. Marengo Kidge, gravel plain on inner border of 295 iLarengo Ridge moraine, correlations of 295-296 distribution of 290-291 relief of 291 structure of the drift in 293-294 thickness of the drift in 29^293 Page. Marengo Ridge moraine, topography of 291-292 Marion, 111., wells near 781 Marion County, 111., altitude of ll general features of 758-759 wells in 758-760 Maroa, 111., wells at 729 Marseilles, HI. , wells at 638 Marseilles moraine, altitude of 309 distribution of 307-308 structuro of drift of 312-313 thickness of drift along 311-312 topo^iraphyof 309-311 Marsh, G. C, Information furnished by 397 Marshall, W. L., report on Chicago Outlet mentioned 419 Marshall, 111., exposure of Sangamon soil at 129 wells at 734 Marshall County, 111., altitude of 10 bowlders in 269 general features of 668-669 wells in 668-669 Martin County, Ind., changes of drainage in 102 drift border in 36 Martinton, 111., wells at 656 Mascoutah,IU., coal shaft at 764 Mason, 111., wells at and near 689,754 Mason County, 111., altitude of 10 general features of 688 wells in 688-689 Material in the abandoned channel of the Mississippi 93-94 Matteson, III., wells near 590 Mattoon, 111., section of drift in coal shaft at 202 wells at 735 Mayview, 111., wells near 702 Maywood, 111., wells near 588-589 Mazon, 111., wells at 647 Mazon Creek, watershed of 508 McCuen, W"., well section of 57 McDunougli County, III. , altitude of 10 general features of 685 wells in 685-686 McGee, W J, cited on border of lowan drift 144,146 cited on gum bo 31 cited on the draiuage systems of eastern Iowa. . 91 cited on the relation of the lllinoiau to the lowan drift 25 cited on the relation of the Illinois and Iowa ice lobes 151-152 McGee, W J, and Calvin, S., cited on lowan and Kansan sheet of northeastern Iowa 139 McGee, W J, and Udden, J. A., cited on the displace- ment of the Mississippi 90 McHenry County, 111., a] titude of 9, 575 situation and area of 575 wells in 575-579 McKee's Creek, watershed of 521 McLean County, Hi. , altitude of 10 buried soil in 265 general features of 692-693 ridge in 244 table of wells in 696 wells in 214-215, 692-697 McLeansboro, 111., wells at 778 McWendle, William, information furnished by 386 Mead, Daniel W., information furnished by 572 well records from report of 556 Medora, III., coal boring at 743 810 INDEX. Page. Meaard County, 111., altitude of 10 general features of 709 wellain 709-710 Mendon.IU., -wells at 715 Mendota, m, -wella at 636-637 Mephiticus tncphitica 42 Mercer County, 111., altitude of -- 9 general features of 622 wells in 622-623 ileriam, 111., wells near 775 Metaniora, 111., wells at 672 Metropolis City.IU., wells 3iear 785 Michigan, drift in southwestern 353 Michigan City. Ind., analysis of clay at 411 depth of gravel at 430 section of boring at 397 section of well at 398 thickness of drift at 392 Milan, 111., fossils found near 174 well at 621 Milburu, 111., wells at 580 Miles, Iowa, drift at 146 Milford, 111., drift sheets at 143 wells near 660 Mill Creek, fossils found at 174 Milledgeville, 111 , well at 613 Miller, Jacob, information furnished by 628 Millington,ni., wells at 644 Millstadt, 111., wells at 762 Milton, 111., wells near 720 Milwaukee, Wis., profile across Lake Michigan at. . . 13 Minonk.m., wells at 670-671 Minooka, HI., wells at 647 Minooka till ridge, distribution of 319 probable line of continuation of 319-320 structure of drift on 321 thickness of drift near 320-321 topography near 320 Mississippi bluff, section at Muscatine, Iowa 47-48 Mississippi Eiver, altitude of rock bottom and pres- ent river 474-476 composition of ridge between Illinois River and . 60-61 deflection at Leclaire 463-464 deflections of, south of glacial boundary 474 determination of the date of excavation of lower rapids 470-473 elevation of the abandoned channel of the 93 limestone belt along 14 material in the abandoned channel of the 93-94 preglacial course of, below Clinton 466-467 reestablishment of, below the lower rapids 473-474 temporary displacement of the 89-97 Mississippi Valley, artesian wells in the 56 drainage for the ice sheet in the - 71 relative sizes of the present and preglacial 468-469 wells in 565 Missouri, glacial deposits in St. Louis County 64 Mitchell. Joseph, information furnished by 125 Moccasin, 111., wells mnxr 754 Modesto, 111., wells at 743 Molino, 111., fossils found at 170-171 Momence, III., limestone at 506 wells at 653 Monmouth, 111., wells at 678 Monon Creek, sand ridge near 330 Mouro(\ HI., wells at 607 Page. Monroe County, III., altitude of 16 general features of 765 wells in 765-766 Mont Clare, artesian well at 56 Monroe County, Ind., changes in drainage in 104 drift border in 36, 70 Montgomery County, 111., altitude of 11 general features of 740-741 wells in 740-742 Montgomery County, Ind., wells in 237 Monticello, HI., section of well at 220 wells at 704 Morgan. County, 111., altitude of 11 general features of 722 wells in 722-724 Morgau County, Ind., drift border in 70 Morgan Park, ill., well at 589-590 Morris, 111., wells at 647 Morris Basin, deposits at the 423 till plain near the ^^15 Morrison, HI., exposure of till at 140 loess at 149 ridges near 134, 150 wells near 617 Morrisonville, HI., wells at 727 Morton, HI., wells at 214, 583, 691 Moweaqua, 111., well at 738 Moultrie County, III. . altitude of 10 general features of 729-730 wells in 729-730 Mound Station ,111., wells at 713 Mount, J- H.. information furnished by 206,207 Mount Auburn, 111., wells at 726 Mount Carmel, 111., wells at 611-612,776 Mount Carroll, III., exposures at 129-130 Mount Morris, 111., wells at 605 Mount Pleasant, Tnd., drift border near 36,69 MountPulaski, 111., wells at 709 Mount Sterling. III., wells at 713 Moweaqua, HI., soil analysis at 162 Muck, buried, at Belleville, 111 763 at Bethany, III 730 atHalton City, 111 217 atBelavan.Hl 206-207,691 at Hopedale, HI 214.692 at Leroy. Ill 695 at Mahomet, 111 703 at iletamora.Ill 672 at Mount Carroll, 111 139-130 atPana.Ill 726 at Rock Island, HI 114 at Windsor, 111 202,739-740 in Christian County, 111 725 in Hewitt County, III 705 iuFord County. Ill 663 in Lasalle County, 111 641,642 in Lee County, Iowa 41 in McLean County, 111 265,696,097 in northern Illinois 185-186 in Rock Island County, HI 620,621 in Vermilion County, 111 698 in Verniilinn County, Ind 233 near Areola. Ill 731 near Alta, HI 207,674 near Danville Junction, 111 699 near Garden Plain, 111 61.'S INDEX. 811 Muck, buried, near Hamilton, HI. near Hey worth, 111 near Letts, Iowa near Marengo, 111 near New London, Iowa near Omaba, 111 near Reynolds, Ind near Springfield, 111 57 215 49 577 52 783 335 125 near Time, 111 63-64, 721 near Wapella, 111 215 near Yariuoutli, Iowa 51 {See Peat, buried; Silt, buried; Soil, buried.) Murphy sville, 111., wells at 780 Muscatiue, Iowa, exposures at 46-48 foasils found at 168-169, 174 section of Mississippi bluff at 47^8 Muscatine County, Iowa, character of wells in 49 drift border in 34, 144 di ift sections in 46-49 Muskegon, Mich., drift at 13 Muskegon Lake, depth of 441 isr. Nachusa, 111., wells at 609 Names of fossils in Pilsbry andJohnson's checklist. 168-171 IS'aperville, 111., wells at 593-594 Nashville, 111. , wells at 770 Nauvoo, 111., wells at 682 Nebo, 111., wells at 721 Neoga, 111., wells at ... 737 Neponset, drift beds in coal shaft at 629 Nettle Creek, watershed of 508 Nevada, 111., wells at 666 Newark limestone 36, 70, 102 New Athens, 111., wells at 765 New Berlin, 111., wells at 725 New Bremen, 111., wells near 590 New Buffalo, Mich., beach at 432-433 depth of gravel at 439 sheets found near 440 thickness of drift at 392 New Haven, 111., knoils near 39 New Lebanon, 111., well at 601 New London, Iowa, sections of wells near 51, 52 New Salem, III., wells at 63,720 Newton, Adams County, 111., section in well south- east of 59 Newton, Jasper County, 111., wells near 754 Newtown, 111., wells near 717 New Troy, Mich., thickness of drift at 392 till at 399 Niagara limestone, mounds of iq Niagara outlet, uplift of 453 Niantic, 111., coal shaft at 728 Nicklea, J. M., cited on Pleistocene deposits near Sparta, HI 117 reference to 769 Niles Center, 111., wells at 588 Nil wood, 111 , wells at 743 Nokomis, 111., wells at 741 Noyes, W. A., analyses made by 164,411 O. Oak Glen, 111., wells at 587 Oakland, 111., wells at 735 Oak Park, 111., section in gravel pit near 438 sheets found near 439-440 Page. Oblong, 111., wells near 750 Odell, HI., wells at 666 Odin, HI., coal boring at 759 Ogle County, 111., altitude of 9 bowlders in 268 general features 604-605 sand and gravel in eastern 278 wells in 604-608 Ohio, 111., well at 629 Ohio Corners, well near 361 Ohio Valley, HI., tillin : 65-66 Old Ripley, 111., wells at 751 Olmstead, 111., wells at 787 Olney, HI., wells at : 757 Omaha, 111., wells near 783 Onarga, 111., drift sheets at 142 wells at 658 Onarga Ridge, description of 289-290 Onslow, Iowa, drift at 145 Outarioville, lU., well at 585 Oquawka, 111., wells at 680 Orangeville, HI., belt of gravelly drift near 81 wells near 568 Oregon, 111., drift bordernear 132 wells at 606 Organic remains 123-124 Orion, 111., wells near 625 Orr, John, information furnished by 397 Oswego, HI., wells at 644 Ottawa, 111., topography near 281-282 wells at 638 Otter Creek, watershed of 523 Otterville, 111., wells at 747 Otwell, 111., borings at 68, 99 Overhall, D., well secticn 749, 750 O verisel, wells at 439 Owen County, Ind., drift border in 36, 70 strije in Oreene County and 87 Owens Creek, sand and gravel deposits along 278 Palatine Township, HI., wells in 585-586 Palmer, 111., coal shaft at 727 Pana, 111., section of well at 107 wells at 726 Papineau, 111., wells at 656 Paris, 111., classification of pebbles at 221 wells at 732-733 well at 201 Parke County , Ind., drift in western 200 wells in 237 Park Ridge, HI., wells at 587 Parnell, 111., well near 705 Patoka, 111., wells at - 759 Patoka, Ind., change in drainage near 100, 101 Patoka River, preglacial and present course of 99-1 02 watershed of 532 Pawpaw, 111., well at 611 Pawpaw Lake, ^ell near 370 Pawpaw River, bay in. the valley of 435 course of 540-541 moraine near, descriptitm of 350-351 sandy belt near 369 Pawpaw Swamp, moraine near 341-342 Paxton, 111., wells at 662-663 Payson, III., wells near 59,717 812 INDEX. Page. Peat, buried, at Ashland, 111 127 at Champaign, 111 2i4 atEvanston.Ill 450,588 at Muscatine, Iowa -18 at Neponsct, 111 629 at Virginia, 111 711 in Christian County, 111 725 in Des Moines County, Iowa 50 ill Iroquoia County, 111 141.655. 656 in Lee County, Io\ra 41 in northern Illinois 185-186 in southeastern Iowa - - . 120-121 near Chel)anse, 111 657 near Clayton, 111 141-U2.661 near Da ven port, Iowa 128 near Edwards River 622 near Letts, Iowa 49 near Mahomet, III 216 near New London, Iowa 52 near Reynolds, Ind 335 near Washington, 111 32 near Wyom ing, 111 672 (See Mucl;, buried; Silt, buried; Soil, buried.) Pecatonica, 111., wells at 572 Pecatoniea Easin, structure of drift in 137-138 Pecatonica esker system 80-81 Pecatonica River, basin-like expansion of valley of. 18 effect of glaciation on 484-485 Peet, S. Conformation furnished by 686 Pekin, 111., wells at 691 Penhallow, D. P., cited on Toronto formation 189 Pentwater Lake, depth of 441 Peoria, 111., exposures near 128,207 glacial deposits near 499 width of the Illinois Valley at 499-500 Peoria County, 111., altitude of 10 bowlders in 269 general features of 673 wells in 073-676 Peorian stage, length of 188-189 Pere Marquette Lake, depth of 441 Perry County, 111., altitude of 10 general features of 771 wells in ■ 771-773 Peru, 111., altitude of rock bottom at 500 wells at 637 Petersburg, 111., wells at 709 Philipstown, 111., \\ells near 777 Philo, 111., section of well at. 235-236 wells at 703 Phinney, A. J., cited on geologic formations in west- ern Indiana 552 Piatt County, 111., altitude of 10 general features of 703-704 well in 234, 703, 704 Pigeon Creek drainage basin, changes in 98 Pike County, 111., altitude of 11 dril't border in 34 general features of 718-719 till in 62 wells in 718-721 Pike County, Ind., changes in drainage in 98, 99 drift border in 35, 37, 40 drift in 68 till in 68-ti9 Pillsbry and Johnson's check list, cited 168-171 PincUni-yvillo, 111., wells at 771 Pine Creek, preglacial excavations along Rock River near Pipestone Creek, course of topography near wells near Pipestone River, moraine near, description of Pittstield, 111., wells at Pitt wood. 111., wells at Plainville, III., drift near wells at Piano, 111. , wells at Plattville, 111., wells near Pleasant Mound, 111., wells at Pleasant Plain, 111., wells at Pleasant Valley, preglacial stream in Pleasant View, III., wells at Pleistocene beds near Sparta, 111., section of Pleistocene deposits beneath thelllinoian till sheet. Plunimers Creek, glacial deposits near Plum River, preglacial and present course of Pocahontas, 111., ridge from Highland to Polo, 111., exposures of lowan drift east of 132, wells at Pontiac, 111., wells at Pope County, 111., altitude of Porter County, Ind., section of artesian well in thickness of drift in Posey County, Ind., changes of drainage in drift in Potomac, 111., wells near Prairie City. 111., wells at Prairie Creek, HI., wells near Pratt, W. H., cited on animal remains in Davenport, Iowa cited on fossils Prentice, 111., coal shaft at Princeton, 111., altitude of rock bottom, at wells at Princeville, 111., wells near Prophetstown, 111., wells near Prospect Park, 111., wells at Pula.ski County, 111., altitude of I'urdue, A. H., aid by ■ work on sand areas Purviance, A. T., information furnished by Putnam City, 111., well at Putnam County, 111., altitude of genenil features of wells in Q. Qnincy, HI., wells at Quiver Creek, watershed of , 189 540 348 372-373 352 721 (i56-057 59 717-718 643-61+ 644 752 725 465-466 712 117 105-118 69-70 478 72-73 138-139 606 G66 11 397 392 97 35,67 698, 700 685 657 127-128 166, 168 723 500 627-628 674 617 593 11 329,412 333 633 634 10 633-634 633-634 714 615 R. Rabbit fossils 42,124 104 13 489 782 753 11 767 73 768 IJaccoon Creek, detlectioD by glacial bouiulary Kacine, Wis., piolile across Lake Micbipni near Kue, E. C and Greenli-af, J. L., estimate of discliarge tlirough Kock River Valley, miule by Kaleigb, 111., wells at '. Ramsey. III., wells near Kanilolpli County, III., altitude of yener.nl features of ridgo in Jackson County and tal)le of well sections in welts iu 767-769 INDEX. 813 Page. Rantoal, 111., wells at 702 Eavinia, 111., section at 386 well at 581 Kead, W, T. B., referred to 584 EedBna.Ill.,w6ll3at 768 Eentchler, Dl., wells at - 764 Kicliardson,IU.,'"^ells near 597 Richland County, 111., altitude of 11 general features of 756-757 wells in 756-757 Kichland Creek, deflection of, by glacial Tjoundary. . . 102-103 drift at 70 Eidgway, 111., knolls near 39 wells near 65, 783-784 Eiggs, E. B., analyses of loess by 164 Eisk.m., wells at 667 Riverdale, 111 ., well at '. 590 Eiver Park. 111., well near 588 Riverside, 111., wells at 589 Robinson, 111., wells at 755 Rochelle, 111., wells at 607-608 Rock Creek, belt of loess in 150 Eockfalls, m., wells at 616-617 Eock floor, table of altitudes of 9-11 Eockford, HI., analyses of sand near 16r^ gorge near 492 well at 572 Rock gorges, measurements of, in northwestern Illinois 494 Rock Island, 111., analyses of loess at 161 exposures of silt near 114 section of well at 114 Eock Island County, 111., altitude of 9 general features of 619-620 table of wells in 620-621 wells in 619-621 Eockport, Ind , loess near 156 Eock Eiver, course of 485, 486^87 descent of the lower portion of 492 drainage basin of 483-493 excavation along, near Pine Creek 489 gravel plain in valley of 490-491 preglacial valley of 483-484 rock excavation in the new course of 487 table of well sections east of, in "Winnebago County, 111 570-572 time of deflection of 491-492 Rock surface, Michigan, Indiana, and Iowa, average altitude of 12 Rockville, drift near 200 Rolfe, C.T7., aidby 7 cited on altitudes in Illinois 7,12 maps of Chicago Outlet by, mentioned 421 records of wells collected by 223 referred to 375, 701 sections of boring reported by 235,236 Rome, Iowa, abandoned channel of the Mississippi River near 90, 92, 93 Roodhouse, HI., wells at 745 Rosebud, 111., wells near 78? EoseUe, HI., wells near 592 Rossville, 111., bowlders at 269 wells at 699 Round Grove, 111., exposure of till at 140 ridge at 135 section of well at ] 39 Page. Ruma, HI., wells near 768 EushviUe, 111., wells at 712 Eussell, I. C, cited on Leaf Eiver or Adeline esker. 77 Rynear, knolls near 230 S. Saginaw lobe, extent of St. Anne, 111., wells at St. Charles, 111., wells near. . St. Clair County, HI., altitude of.. 341 654 597 11 general features of 761-762 wells in 761-765 St. Francisville, HI., wells at 756 St. George, 111., wells near 654 St. Jacobs, 111., wells at 750 St. Johns, 111., borings at 772-773 St. Joseph, Mich., thickness of drift at 13, 392 well at 400 St. Joseph Eiver, drainage basin of 540 gravelly plain on 434-4?5 moraine near 342, 352-353 structure of drift along 399-400 St. Louis, Mo., deposits near 64, 71 drift border near 35, 37, 39 limestone belt near 14, 15 St. Louis County, Mo., glacial deposits in 64-65 St. Marie, 111., well at 755 St. Mary's, 111., wells at 656 St. Mary's, Ind., drift at 201 silt near 208 Salem, 111., coal boring at 759 Saline County, 111., general features of. 781-782 wells i n 78 1-782 Saline Eiver, course of , 527-528 Salisbury, E. D., cited on drift in southeastern Illinois and southwestern Indiana 109 cited on glaciation of limestone ridges 15 cited on mineralogical constitution and size of lowan loess 158-159 cited on the drift border 37 fossils collected by 168 glacial work of 3 reference to 43, 160, 166, 543, 547, 714, 745 Salisbury, R.D., and Chamberlin, T. C, cited on the drift border in southern "Wisconsin 43-44 Salt Creek, course of 504 gravel pit between Lagrange and 438 old bay in basin of 431-432 outwash in valley of 211 topography near 345 Sandoval, 111., wells at 759 Sand wich. 111., wells at 604 Sandy Creek, watershed of 513 Sanford, 111., section of drift at .'... 201 Sangamon, analyses of bowlder clays at 163 width of the Illinois Valley near 499 Sangamon County, 111., altitude of 10 general features of 724 wells in 724^725 Sangamon Eiver, exposures near Mahomet, on 21G drift in the valley of 214 outwash in valley of 210-211 topography near 227 watershed of 517-520 San Jose, 111., wells at 089 Saunemin, 111., wells at 667 814 INDEX. Page. Savanna, IlL, fosaila found at 166, 168 well at 611 Sawyer, Mich., section at 399 well at 439 Sawyer Station, Mich, thickness of drilt at 392 Saybrook, Til., wells at 695 Schererville, depth of sand at 439 Schernierville, 111., wells near 587 Scblemming;J., information furnished by 613 Scotland, Ind., till at 69 Scottville, 111., wells at 743 Scovell, J. T., on striae in Wabash Valley 87 Schuyler County, HI., altitude of 10 general features of 71 1-712 wells in 711-712 Scott County, 111., altitude of U general features of 721-722 weUsin 721-722 Scott County, Iowa, exposures in 46 Senachwine Creek, watershed of 513 Seneca, 111., wells at 638 Shannon, 111., wells near 613 Shaw, .J;imes, cited on Leaf Eiver or Adeline esker. . 76 cited on well at Princeton, 111 628 information furnished by 612 Shawnee Township, Ind., outwash in 239 Sliawneetowu, 111., boring at 65-66 wells at 784 Shelby County, 111., altitude of 10 general features of 737-738 wollftin 737-740 Shelbyville, 111., silt near 198-199 wells at 739 Shelbyville drift sheet, extent of 192 Shelbyville moraine, character and extent of 192- 213 character of the outwash from 208 distribution of 193-194 range in altitude of 194-195 relief of 194 structure and thickness of the drift of 197-208 table of striae within limit of 412-414 topography of 395-197 topography of the inner-border tract 213 ShelbjTille till sheet, thickness of the inner-border tract 213 Sheldon, 111., analyses of bowlder clays at 163 wells near 659-660 Sherbuniville, 111., wells at 654 Shiloh Hill, 111., wells at 769 Shimek, B., cited on distribution, of fossils 165 cited on Limnaia 172 list of fossils revised by 168-169 notes on fossils 171-176 quoted on loess foaails 175-176 Shi rley, 111., wells at 695 Shoal Creek, watershed of 524-525 well in valley of 751 Shovotail Slough, 111., wells at 661 Shufeldt, George A., jr., referred to 584 Sidney, 111., section in boring at 2.36 wells at 702-703 Siebenthal, C. E., cited on deflections of White River .".33 cited on deflections of small streams by glacial boundary 102-103 cited on drift in Morgan County 70 Page. Siebenthal, C, E., cited on drift in Owen County 70 cited on the glacial boundary 36-37 reference to 38, 88, 104 Silt, buried, at Atlanta, III 206 at Monticello, III 220 at Muscatine, Iowa 47 at Stratford, III 138,606 in Adams County, 111 61, 62 in Muscatine County, Iowa 40 in northwestern Illinois 111-118 in Rock Island County, III 621 on east bluff of Mississippi River 115 near Keokuk, Iowa 94 near Mahomet, 111 237 near Washington, 111 32 near Yarmouth, Iowa 51 Silver Creek, watershed of 525-526 Silveria formation 112-118 Simpson. C. T., fossils identified by . . 115, 1G8, 169, 170-171, 451 Skunk River, interglacial course of 122-123 Sloat, William, well section of 51 Smith, F. , well section of 51 Smithboro, 111. , coal boring at 751 Snyder, J. F., fossils collected and identified by 171 information furnished by 711 quoted on section at Virginia, HI 108 Soil, buried, at and near Coatsburg, 111 62, 109, 716 at and near Davenport, Iowa 45, 128 at and near Keokuk, Iowa 94, 95, 96 at Arlington Heights 587 at Ash Grove, 111 661 at Atlanta. Ill 206,708 at Clayton, 111 660 atDalton, 111 730 at Decatur, 111 204 at Elkhart, 111 709 atGalva,Ill 130,624 at Iroquois. Ill 659 at Kansas, 111 217 at Marengo, 111 293 at Muscatine, Iowa 47 at Pana, 111 107 at Piano, 111 644 at Rockville, 111 200 at Roundgrove, 111 139 at St. Charles, 111 597 at Salem. Ill 759 at Shavetail Slough 661 atlJrbana, 111 235 at Virginia, III 108,711 at Woodstock, 111 577 between Dudley and Kansas, HI 733 between Oregon and Mount Morris. Ill 606 depth of. in Illinois 263-266 elevation where it occurs 29 exposures of, near Henton, 111 59 in Adams County, HI 61 in Alden, 111 576 in Bureau County, HI 264,627 in Champaign County, 111 240.701 in Clark County, 111 733 iuCook County, 111 583,586 in Dokulb County, III 264 in Donniiirk, Iowa 55 in Dowitt County, 111 705 in Ford County, 111 664 INDEX. 815 Soil, buried, in Hancock and Adams conntiea, 111 in Iroquois County, 111 141. in Kane County, 111 263-264,301, in Kankakee County, 111 in Kendall County, 111 in Lasalle County, 111 264, in Lee Countj', 111 in Lee County, Iowa in McLean County, 111 265, in Ogle County, 111 in Parke County, Ind in southeastern Iowa in Vermilion County, 111 in "SVill County, 111 on east bluff of the Mississippi Eiver near Baylis, 111 near Belvidere, 111 near Clinton, 111 near Crescent, 111 near Denmark, Iowa near Elgin ,111 near Greenup, HI near Hamilton, 111 near Lily Lake, 111 near Mabomet, 111 near Marshall, 111 near Milton, 111 near Mount Carroll, 111 near Mount Pulaski, HI near Newton, 111 near Tbawville. Ill near W apella. Ill near Washington, 111 near West Point, Iowa Somonauk Creek, knolls along Sorento, 111., wells near South Fork, watershed of South Haven, Mich., section of boring in thickness of drift at South Kisbwaukee Kiver, sand and gravel deposits on topography near South Riley, 111., wells at Sparta, HI., section of Pleistocene beds near wells at Spaulding Station, HI., well near Spencer, J. W., cited on uplift of Niagara outlet Spoon Eiver, watershed of gravel deposits near valley of Springfield, 111., generalized section of wells north- west of wells at Spring Hill, HI., exposures near paha near . wells near Spring Lake, depth of Stark, HI., wells near dtark County, 111., altitude of general features of wells in Staunton, HI., wells at Steeleville, 111., wells at Stephenson County, 111., altitude Of area of silt deposit in table of well sections in Page. 105, 106 265, 657 597, 598 325, 654 645 641, 642 264 40,52 693, 696 607 200 120-121 698 651 U5 720 139 205 659 54 585, 596 127 57 294 216 129 720 612 709 717 661 706-707 32 53,70 287-288 751 519 401 392 278 246-247 578 117 769 585 453 516-517 276-277 125 725 133, 140 135 618 441 672 10 672 672 743-744 769 9 567 113 568-569 Stephenson County, HI., transported rock ledges near Dakota 83 wells in 567-569 Sterling, HI. , wells at 616-617 Sterling, Iowa, glacial deposits near 146 Stillman Valley, HI ., wells near 606 Stillwell, 111., filled valley near 51 Stilter, William, well section of 42 Stockton, wells in preglacial valley north of 566 Strata, altitude of, in Illinois 553-554 Stratford, exposure of fossiliferous silt at 138 wells at 606 Strawn, 111. , wells at 667 Streator, 111., wells at 639 Strife, glacial 84-88 at Burlington 85-86 near Hamilton ,111 105 outside the Shelbyville moraine (table) 88 Stronghurst, 111., wells at 680 Structure of drift border in southeastern Iowa 40-43 Sugar Creek, belt of gravel on 272-273 course of 536 gravel terraces in valley of 239 watershed of 519, 536 Sugar Grove Township, 111., wells in 599 Sullivan, IlL, depth of drift at 217 wells at 730 Summerfieldjll., wells at 763 Summit, 111., wells at 589 Sumner, HI., wells near 756 Swan wick, 111., wells at 771 Sweet, T, 0.. information furnished by 371 Sweetwater, 111., wells at 710 Sycamore, HI., wells at 603 Sykes, J., well section of 60 T. Taylor. F. B., ci ted on the beaches of Lake Michigan . 420 suggestion by 356 Taylorville, lU ., wells near 726 Tazewell County, 111., altitude of 10 general features of 689-690 thickness of drift in 265 wells in 689-692 Terre Haute, Ind., analyses of loess near 164 Texas City, III., wells at 782 Thawville, 111., wells at 661 Thebes. 111., deflection of the Mississippi River at. . . 474 well at 786 Thomasville, 111., wells at 741 Time, HI., exposures and wells at 63 wells at 721 Timpe. F., well section of 53 Tippecanoe River, altitude near 331-332 sand ridge along 329 Todd, J. E.. cited on drift deposits 37 cited on strite at Alton, 111 86 Toledo, 111., wells at 737 ToUeston beach, altitude of 452 composition of, in Illinois 450 composition of, in Indiana 450 course of 447-450 Tolono, drift at 233 Toluca, 111., wells at 669 Toronto formation 20, 185, 189-190 Totemeir, Anton, information furnished by 51 816 INDEX. Page. Touluo.Ill., weilaat 672 Tower Hill, III., wells at 739 Townsliips, method of numberiDg 4-6 Trail Creek, drainage basin of 539 old bay in valley of 432 Troy, 111., wells at 750 Tme, F. W., cited on bones found in peat 42 examination of animal remains by 124 Turkey Creek, ridge along 387 Turner Junction, 111., wells at 593 Turner Park, 111., wells near 588 Tuscola, 111., well s at and near 222, 731 Tyrrell, J. P., cited on separation of Albertan and sub-Aftonian drift sheets 21 TJ. Udden. J. A., aid by 114, 147, 148, 187 analysis of loess by 159 cited on loess deposition 177, 179 cited on old lake bed in Muscatine County, Iowa 96 cited on the rock constituents of the drifts of Muscatine County 44 cited on wells in Rock Island County 621 fossils collected by 115, 168, 1 70-171, 173-174 information furnished by 412, 616. 618, 620, 624, 625, 630, 634 investigation of the preglacial course of the Mississippi 463,465,466 trip with 145-146 well record obtained by 615 TJdden, J. A., Calvin, Samuel, and Baiu, H.Foster, w ork on drifts 44-45 Udden, J. A., and ^McGee, W J, cited on the displace- ment of the Mississippi 90 Underground waters, classification of 550-55 Unio fossils 167 Union County. HI., altitude of 11 Union Grove, 111., wells near 616 Union Hill, 111., wells at 654 Urbana, 111., section of boring at 235 wells at 702 Ustick, 111., wells near 615 Utica.ni., wellsat 638 Valleys, preglacial 17,18 Valparaiso morain ic system, altitude of, range in . . . 343-344 distribution of 339-340 drainage of the 379 drift, thickness of 353-355 eastern border of 340-341 topography of 345-348 Van lluren County, Mich., thickneaa of drift in 355 wells ill 366,367,368,370,371,372 Vandaha. 111., wells near 752-753 Vanderburg County, Ind., change of drainage in . . . 97 drift border lu 35 wells in 67 Van Tnyl, S., well section of 54 Vclpen, Inil., col near 100 Vermilion County, 111., altitude of 10 drift structure in 267 general features of 697-608 till idain in 239-240 wolla in 697-700 Page. Vermilion Kiver, course and watershed of the "Wa- bash 53&-537 Vermilion River, drift structnre along 283 moraine near 279 sand ridge near 330 topography near 311 watershed of 511 Vermilion ville, HI., well at 6:19 Vermont, 111., wells at 68« Verona, 111., wells at 647 Versailles, 111., wells at 713 Vicksburg, Miss., analysis of loess at 164 Vienna, HI., wells at 786 Virden, wells at 743 Virginia, 111., analysis of bluff loess at 160,161 fossils found at 171 section at 108 weUsat 127,711 Wabash County, 111., altitxide of 11 general features of 775 wells in 775-776 "Wabash River, deflections of 530 drainage basin of 528-529 gravel terraces in valley of 238 knolls east of 228-229 outwash in valley of 208-209 preglacial valley of 529-530 strife in valley of 87 "Wallace, S. J., relerence to 95 "Wapella, 111., wells at 215,706 Warren, G. K., cited on preglacial channel of the Mississippi River 469 "Warren, altitude of 566 wells near 566 Warren County, III., altitude of 10 general features of 678 ' wellsin 678-679 Warrick County, Ind ., changes of drainage in 98 Warsaw, HI., analysis of soil at 163 exposures at 94-95 wells at 683 Washbrrns Mound 299 Washington, 111., section of a cutting near 32 wells at 690-691 Washington County, 111., altitude of 11 general features of 770 wells in 770 Washington Heights, 111., well at 589 Waleiliio, 111., wfUsat 766 Waterloo quartzite, movement of 110-111 Water supply, sources of, for towns in lUiuois 558-564 Watseka, HI., wells at 659 Wancond, 111., wells near 580 Waukegan, 111., beach near 429 wells at 5811 Waupecan Creek, watershed of 508-501) Waverly. HI., wells at 724 Wayne, 111., wells near 592 Wayne County, 111., altitude of U general features of 774 wellsin 774-775 Waynesville. 111., wells at 706 Wellington, HI., wella at 660 INDEX. 817 Tagr. W^ls, artesian, conditions for 555-556 "SVenona, 111., weUs at 669 "West Point, Iowa, exposure of Sangamon soil at 129 sections near 5:-J, 70 West Salem, 111., wells near 776 Wheaton, 111., wells at --■ 593 "Wheeler, H. A., cited on drift deposits 37 Wheeler, Ind., section of ridge north of 396 "White, C. A., cited on animal remains at Davenport, Iowa 127, 128 cited on peat bed at Davenport, Iowa 128 reference to :- 88 White County, 111., altitude ot H general features of 776-777 wells in 776-777 "Whitehall, 111., wells at 745 "White Lake, depth of *41 "White Eiver, course and watershed of 532-534 pregliicial and present course 10-1 preglacial valley of 534 "Whitney, Milton, aniilyses of loess by 159, 160 quoted on analyses of white clay 796 quoted on hluft' loess 794 quoted on howlder-clay soils of Illinois 792 quoted on soils 789-790 "Whiteside County, 111., altitude of 11 general features of 148, 614^615 loess deposit in 154 table of wells in - 617 wells in 614-619 "Will County, ni., altitude of 10 general features of : - - 648-649 table of wells on Valparaiso morainio system id. 650-651 table of wells outside the Valparaiso raorainic system 652 wells in 648-652 "Williams, L., wells drilled by 49-50 Willliamstield, 111, wells at 677 "William-son County, 111., altitude of 11 general features of 780-781 "Wilmette, lll.,wellat 587 "Wilmington, 111., wells at 650 "Wilson, James H., report upon the survey of the Illinois Eiver mentioned 418 "Winchell, Alexander, cited on bowlders in Van Buren County 358 cited on deep channels along east shore of Lake Michigan 441 "Winchester, 111., wells near 722 "Windsor, 111., wells at 202,739 "Wine Hill, 111., wells at 769 "Winfleld, Iowa, abandoned valley near 90, 91, 92, 93 "Winnebago County, altitude of 9 gravel knolls in 136 situation and area of 569-570 table of well sections in 570-572 till ridges in 135 wells in 569-573 Page. Wmiietkrt, Ill.,driltnear 385 till ridge near 381-382 well at 587 "Wisconsin, altitude of 7 "Wisconsin and lowan drift sheets, soil and peat be- tween 185-186 "Wisconsin drift, character of 141-143 beached loess beneath the 187-188 limits of 262-263 "Wisconsin drift sheets, extent of early 191. Wisconsin, structure of drift border in southern .... 43-44 Witter, F. M., fossils identified by 168-169 cited on mammalian remains in loess 166,167 cited on wells in Louisa County, Iowa 49 "Woburn.ni., wells at., 752 Woodford County, 111., altitude of 10 general features of .- 670 wells in 264,670-672 Woodstock, 111., wells at 577 Woodworth, J. E., cited on !N"antucket as a morainal island, S.C.Curtis and 272 Woolridge, C. W., cited on the deep channels along east shore of Lake Michigan 441 Wooster, L. C, geologic work of 3, 339 Worth, III., bowlders near 426 wells at 690 Worthen, A. H., cited on drift deposits 37 cited on drift phenomena of northwestern Illi- nois 76 cited on changes in drift structure at Clinton.. 205 cited on mammalian remains in loess 166 cited on Niagara limestone areas 16 cited on section at Virginia, 111 108 cited on section of well at Paua, 111 107 cited on the interval of degluciation 125 reference to 2,157,526,714,726 AVright, G. F., cited on drift deposits 37 cited on strife in Williamson and Jackson coun- ties, Illinois 87 Wyoming, 111., analysis of soil at 102 wells near 672 X. Xenia, 111., wells at 758 Y. Yarmouth. Iowa, bones found in peat near 42 sections of wells near 42,51 Yarmouth soil near DenmarK, Iowa 54 Yates, 111., wells at 677-678 "Yellow banks " section near Keokuk, Iowa 94 Yellow River, watershed of the 507 Yorkville, 111., wells at 644 Z. Zeeland Ridge, altitude of 391 course of 390-391 MON XXXVIII- -52 A.D ^^ E R T I S EM:E INT T. [Monograph XXXVIII.] The statute approved March 3, 1879, establishing the United States Geological Survey, contains the following provisions : "The publications of the Geological Survey shall consist of the annual report of operations, geo- logical and economic maps illustrating the resources and classification of the lands, and reports upon general and economic geology and paleontology. The annual report of operations of the Geological Survey shall accompany the annual report of the Secretary of the Interior. All special memoirs and reports of said Survey shall be issued in uniform quarto series if deemed necessary by the Director, but othervf iseiu ordinary octavos. Three thousand copies of each shall be published for scientific exchanges and for sale at theprice of publication ; and all literary and cartographic materials received in exchange shall be the property of the United States and form a part of the library of the organization : And the money resulting from the sale of such publications shall be covered into the Treasury of the United States." Except in those cases in which an extra number of any special memoir or report has been sup- plied to the Survey by special resolution of Congress or has been ordered by the Secretary of the Interior, this office has no copies for gratuitous distribution. ANNUAL REPORTS. . I. First Annual Report of the United States Geological Survey, by Clarence King. 1880. 8°. 79 pp. i map. — A preliminary report describing plan of organization and publications. II. Second Annual Report of the United States Geological Survey, 1880-81, by J. W. Powell. 1882. 8°. Iv, 588 pp. 62 pi. 1 map. III. Third Annual Report of the United States Geological Survey, 1881-'82, by J. W. Powell. 1883. 8°. xviii, 564 pp. 67 pi. and maps. IV. Fourth Annual Report of the United States Geological Survey, 1882-'83, by J. W. Powell. 1884. 8°. xxxii, 473 pp. 85 pi. and maps. V. Fifth Annual Report of the United States Geological Survey, 1883-'84, by ,J. W. Powell. 1885. 8"^. xxxvi, 469 pp. 58 pi. and maps. VI. Sixth Annual Report of the United States Geological Survey, 1884-85, by J. W. Powell. 1885. 8°. sxix, 570 pp. 65 pi. and maps. VII. Seventh Annual Report of the United States Geological Survey, 1885-'86, by .J. W. Powell. 1888. 8°. XX, 656 pp. 71 pi. and maps. VIII. Eighth Annual Report of the United .States Geological Survey, 1886-'87, by J. W. Powell. 1889. 8°. 2 pt. xix, 474, xii pp., 53 pi. and maps; Iprel. leaf, 475-1063 pp., 54-76 pi. and maps. IX. Ninth Annual Report of the United States Geological Survey, 1887-'88, by J. W. Powell. 1889. 8^. xiii, 717 pp. 88 pi. and maps. X. Tenth Annual Report of the United States Geological Survey, 1888-89, by J. W. Powell. 1890. 8^. 2 pt. XV, 774 pp., 98 pi. and maps; viii, 123 pp. XI. Eleventh Annual Report of the United States Geological Survey, 1889-'90, by J. W. Powell. 1891. 8". 2 pt. XV, 757 pp., 66 pi. and maps; ix, 351 pp., 30 pi. and maps. XII. Twelfth Annual Report of the United States Geological Survey, 1890-'91, by J. W. Powell. 1891. 8°. 2 pt., xiii, 675 pp., 53 pi. and maps; xviii, 576 pp., 146 pi. and maps. ■ XIII. Thirteenth Annual Report of the United States Geological Survey, 1891-'92, by J. W. Powell. 1893. 8°. 3 pt. vii, 240 pp., 2 maps; x, 372 pp., 105 pi. and maps; xi, 486 pp., 77 pi. and maps. XIV. Fourteenth Annual Report of the United States Geological Survey, 1892-'93, by J. W. Powell. 1893. 8°. 2 pt. vi, 321 pp., 1 pi. ; xx, 597 pp., 74 pi. and maps. XV. Fifteenth Annual Report of the United States Geological Survey, 1893-'94, by J. W. Powell. 1895. 8°. xiv, 755 pp., 48 jil. and maps. XVI. Sixteenth Annual Report of the United States Geological Survey, 1894-95, Charles D. Walcott, Director. 1895. (Part I, 1896.) 8°. 4 pt. xxii, 910 pp., 117 pi. and maps; xix, 598 pp., 43 pi. and maps; xv, 646 pp., 23 pi. ; xix, 735 pp., 6 pi. XVII. Seventeenth Annual Report of the United States Geological Survey, 1895-'96, Charles D. Walcott, Director. 1896. »\ 3 pt. in 4 vol. xxii, 1076 pp., 67 pi. and maps; xxv, 864 pp., 113 pi. and maps; xxiii, 542 pp., 8 pi. and maps; iii, .543-1058 pp., 9-13 pi. XVIII. Eighteenth Annual Report of the United States Geological Survey, 1896-'97, Charles D. Walcott, Director. 1897. (Parts II and III, 1898.) 8°. opt. in 6 vol. 1-440 pp., 4 pi. and maps; i-v, I II ADVERTISEMENT. 1-653 pp., 105 pi. anil maps; i-v, 1-8H1 pp., US pi. and iiia|is: i-x, 1-7511 pp., 102 dI. .'inil maps: i-xii, 1-1)12 pp., 1 pi. ; 043-1100 pi>. XI.\. Niuetnenth Aii'ual Report of the United .States Geological Snrvi-y, 18y7-"9S, Cliarles D. Walcott, Directoi-. 1808. 8. pt. iu 7 vol. MONOGRAPHS. I. Lake Bouneville, by Grove Karl Gilbert. 1890. 4^. xx, 438 pp. 51 pi. 1 map. Price $1.50. • II. Tertiary History ot'theGraud Canon District, with Atlas, by Clarence E. Dnttou, Capt., U. S. A. 1882. 4^. xiv, 204 pp. 42 pi. and atlas of 24 sheets folio. Price $10.00. III. Geology of the Comstock Lode and the Washoe District, with Atlas, by George V. Becker. 1882. 4^. XV, 422 pp. 7 pi. and atlas of 21 sheets folio. Price $11.00. IV. Conistock Mining and Miners, by Eliot Lord. 1883. 4^'. xiv, 451 pp. 3 pi. Price $1.50. V. The ('(ippm-lJearing Kocks of Lake Superior, by Roland Duer Irving. 1883. 4^. xvi, 464 pp. 15 1. 20 pi. and maps. Price $1.85. VI. Contributions to the Knowledge of the Older Mesozoic Flor.a of Virginia, by William Morris Fontaine. 1883. 4-. xi, 144 pp. 54 1. 54 pi. Price $1.05. A'll. Silver-Lead Deposits of Eureka, Nevada, by Joseph Story Curtis. 1884. i-^. xiii, 200 pp. 16 pi. Price $1.20. A'lII. Paleontology of the Eureka District, by Charles Doolittle Walcott. 1884. 4^. xiii, 298 pp. 241. 24 pi. Price $1.10. IX. Brachiopoda and Lamellibranchiata of the Raritau Clays and Greeusand Marls of New Jersey, by Robert P. Whitfield. 1885. 4^\ xx, 338 pp. 35 pi. 1 map. Price $1.15. X. Dinocerata. A Monograph of .in Extinct Order of Gigantic Mammals, by Othniel Charles Marsh. 1886. 4^. xviii, 243 pp. 56 1. .56 pi. Price $2.70. XI. Geological History of Lake Lahontaii, a yuaternary Lake of Northwestern Nevada, by Israel Cook Russell. 1885. 4"-'. xiv, 288 pp. 46 pi. and maps. Price $1.75. XII. Geology and Mining Industry of Leadville, Colorado, with Atlas, by Samuel Franklin Emmons. 1886. 4-. xxix, 770 pp. 45 pi. and atlas of 35 sheets folio. Price $8.40. XIII. Geology of the Quicksilver Deposits of the Pacific Slope, with Atlas, by George F. Becker. 1888. 4'=. xix, 486 pp. 7 pi. and atlas of 14 sheets folio. Price $2.00. XIV. Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the Connecticut Valley, by ,Iohn S. Newberry. 1888. 4-'. xiv, 152 pp. 26 pi. Price $1.00. XV. The Potomac or Younger Mesozoic Flora, by William Morris Fontaine. 1889. 4'^. xiv, 377 pp. 180 pi. Text and plates bound separately. Price $2.50. XVI. The Paleozoic Pishes of North America, by John Strong Newberry. 1889. 4°. 340 pp. 53 pi. Price $1.00. XVII. The Flora of the Dakota Group, a Posthumous Work, by Leo Lesquereux. Edited by F. H. Knowltrtu. 1891. 4^\ 400 i>p. 66 pi. Price $1.10. XVIII. Gasteropoda and Cephalo])oda of the Raritan Clays and Greeusand Marls of New .Jersey, by Robert P. Whitfield. 1891. 4-. 402 pp. 50 pi. Price $1.00. XIX. The Penokee Iron-Bearing Series of Northern Wisconsin and Michigan, by Roland D. Irving and C. R. Van Hi.se. 1892. 4^. xix, .534 pp. Price $1.70. XX. Geology of the Eureka District, Nevada, with an Atlas, by Arnold Hague. 1892. 4". xvii, 419 pp. 8 1)1. Price $5.25. XXI. The Tertiarv Rhynchophorous Coleoptera of the United States, by Samuel Hubbard Scud- der. 1893. 4-'. xi, 206 pp." 12 ]d. Price 90 cents. XXII. A Manual of Topographic Methods, by Henry Gannett, Chief Topographer. 1893. 4°. xiv, 300 pp. 18 pi. Price $1.00. XXIII. Geology of the Green Mountains in Massachusetts, by Raphael Piimpelly, T. Nelson Dale, andJ.E. Wolff. 1894. 4^. xiv, 206 pp. 23 pi. Price $1.30. XXIV. Mollusca and Crustacea of the Miocene Formations of New Jersey, by Robert Parr Whit- field. 1894. 4". 193 pp. 24 pi. Price 90 cents. XXV. The Glacial Lake Agassiz, by Warren Upham. 189.5. 4-. xxiv, 658 pp. 38 pi. Price $1.70. XXVI. Flora of the Aniboy Clays, by John Strong Newberry; a P. sthumous Work, edited by Arthur Hollick. 1895. 4^. 260 pp. 58 pi. Price $1.00. XXVII. Geology of the Denver Basin in Colorado, by Samuel Frauklin Emmons, Whitman Cross, and George Homans Eldridge. 1896. 4^^. 556 pp. 31 pi. Price $1..50. XXVIII. The Manjuette Iron-Bearing District of Michigan, with Atlas, by C. R. Van Hise and W. S. Bayley, including a Chapter on the Republic Trough, by H. L. Smyth. 1895. 4". 608 pp. 35 pi. and atlas of 39 sheets folio. Price $5.75. XXIX. Gecdogy of Old Hampshire County, Massachusetts, comprising Franklin, Hampshire, and Hampden Counties, by Benjamin Kendall Emerson. 1898. 4''. xxi, 790 pp. 35 pi. Price $1.90. XXX. Fossil Medusa', by Charles Doolittle Walcott. 1898. 4^'. ix,201pp. 47 pi. Price $1.50. XXXI. (ieology of the Aspen Mining District, Colorado, with Atlas, by .Josiah Edward Spurr. 1898. 4''. XXXV, 260 pp. 43 pi. and atlas of 30 sheets folio. Price $3.60. XXXII. (ieology of the Yellowstone National Park, Part II, Descriptive Geology, Petrography, ' and Paleontologv.bv Arnohl llagui!, J. P. Iddings, W. Harvev Weed, Charles D. Walcott, G. H. Girty, T. W. Stanton, and F. II. Kiiowlton. 1899. 4\ xvii, 893 pp. 121 pi. Price . XXXIII. Gecdogy of the Narragaiisett Basin, bv N. S. Slialer, .). B Woodwnrth, and August F. Foerste. 1899. 4". xx, 402 pp. 31 pi. Price . ' ADVERTISEMENT. Ill XXXIV. The rUnoinl Grnvels of Jlaiiic auil their Associated Deposits, by George H. Stono. 1899. 4^'. xiii, 1. 9 pp ."iJ ji-. i'li^o . XXXV. i'he Later Extinct Floras of North America. ])j John Strong Newberry; edited bv Arthur Hollick. 1898. 4^~. xviii, 295 pp. 68 pi. Price $1.2.5. XXXVI. The Crystal Falls Iron-Bearing District of Michigan, by J. Morgan Clements and Henry Lloyd Smyth; with a Chapter on the Sturgeon River Tougue, by William Shirley Bayley, and an introduction by Charles Richard Van Hise. 1899. 4°. xxxvi, 512 pp. 53 pi. Price . XXXVII. Fossil flora of the Lower Coal Measures of Missouri, by David White. 1899, 4-. xi, 167 pp. 73 pi. Price . XXXVIII. The Illinois Glaciiil Lobe, by Frank Leverett. 1899. 4^. xxi, 817 pp. 24 pi. Price . Jnprcpaialion: — Flora of the Laramie and Allied Formations, by Frank Hall Fnowlton. BULLETINS. 1. On Hypersthene-Andesite anil on Triclinic Pyroxene in Augitic Rocks, by Whitman Cross. with a Geological Sketch of Buft'alo Peaks, Colorado, by S. F. Emnious. 1S83. 8^. 42 jip. 2 pi. Price 10 cents. 2. Gold and Silver Cimversion Tables, giving the Coining Vahies of Troy Ounces of Fine Metal, etc., computed by Albert Williams, jr: 1883. 8'^. 8 pp. Price 5 cents. 3. On the Fossil Faunas of the Upper Devonian, along the Meridian of 76^' 30', from Tompkins County, N. Y., to Bradford County, Pa., by Henry S. Williams. 1884. 8'-. 36 pp. Price 5 cents. 4. On Mesozoic Fossils, by Charles A. White. 1884. 8-. 36 pp. 9 pi. Price 5 cents. 5. A Dictionary of Altitudes in the United States, compiled by Henry Gannett. 1884. 8°. 325 pp. Price 20 cents. 6. Elevations in the Dominion of Canada, by J. W. Spencer. 1884. 8°. 43 pp. Price 5 ceiits. 7. Mapoteea Geologica AmeTicana. A Catalogue of Geological Maps of America (North and South), 1752-1881, in Geographic and Chronologic Order, bv Jules'Mai-eou and John Belknap Marcon. 1884. 8'-. 184 pp. Price 10 cents. 8. On Seeoudaiy Enlargements of Mineral Fragments in Certain Rocks, by R. D. Irving and C. R. A^an Hise. 1884. 8-. 56 pp. 6 pi. Price 10 cents. 9. A Report of Work y Carl Barus. 1889. 8°. 313 pp., iucl. 1 pi. 11 pi. Price 25 cents. 55. Rejiort of Work done in the Division of Chemistry and Physics, mainly during the Fiscal Year 1886-'87. Frank Wigglesworth Clarke, Chief Chemist. 1889. 8". 96 pp. Price 10 cents. 56. I'ossil Wood and Lignite of the Potomac Formation, by Frank Hall Kuowlton. 1889. 8^. 72 pp. 7 pi. Price 10 cents. 57. A Geological Reoonnoissance in Southwesteru Kansas, by Robert Hay. 1890. 8"^. 49 pp. . 2 pi. Price 5 lents. 58. The Glacial Boundary in Western Pennsylvania, Ohio, Kentucky, Indiana, and Illinois, by George Frederick Wright, with an Introduction by Thomas Cbrowder Chamberlin. 1890. 8-^. 112 pp., incl. 1 pi. 8 pi. Price 15 cents. 59. The (ialibros and A.S80ciated Rocks in Delaware, by Frederick D. Chester. 1890. 8". 45 pp. 1 pi. Price 10 cents. 60. Report of Work done in the Division of Chemistry and Physics, mainly during the Fiscal Year 1887-'88. F. \V. Clarke, Chief Chemist. 1890. 8-. 174 i)p. Price 15 cents. 61. Contributions to the Mineralogy of the Pacitic Coast, by William Harlow Melville and Wal- demar r>inilgren. 1890. 8°. 40 pp. 3 pi. Price 5 cents. 62. The Gn^enstone Schist .\reas of the Menominee .and Marquette Regions of Michigan, a Con- tribution to the Subject of Dyuaniic Metamorphism in Eruptive Rocks, by George Huntington Williams, with an Introduction by Roland llucr Irving. 1890. 8 . 241pp. 16 pi. Price 30 cents. 63. A Hibli(igra|)liy of Paleozoic Crnstaci'a from 1698 to 1889. including a List of North Amer- ican Species and a Systcnuitic .\rrangcment of (ieuera, by Anthony \V. Vogdes. 1890. 8*^. 177 pp. Pritur(> Work in I^iifoiis I'lisicm ami Klnillition, lUidly in Reliiti"ii to Pi-pssiire, ly Carl Ii.trns. ]sn". S\ 57 pp. 9 pi. I'licc I.) cuiits. 104. Gluciation of tbe YeUowstone Valley iiortli of the Park, liy Walter Harvey Weed. 18H3. 8^. 41 pp. 4 pi. Price 5 cents. 105. The' Laramie aud the Overlyiiin- Liirin^jstone Forinatiou in Montana, hy Walter Harvey AVeeil, with Report on Flora, l)y Frank Hal! Knowltoii. 1.S93. 8-. 68 pp. 6 ])1. Price 10 cent.s. 106. The t'olorado Formation and its Invertebrate Fanna. liy 'J'. W. Stanton. 1893. 8-. i?88 pp. 45 pi. Price 20 cents. 107. Tlie Traji Dikes of the Lake Chamidain Rcsjion, by .lames Fiirman Kemp aud Vennm Freeman JIarsters. 1S93. 8-. 62 pp. 4 pi. Price 10 cents. 108. A Geological Recounoissance in Central Washington, by Israel Cook Russell. 1893. 8-. 108 pp. 12 pi. Price 15 cents. 109. The Eruptive and Sedimentary Rocks on Pigeon Point, Minnesota, and their Contact Phe- nomena, by William Shirley Bayley. 1893. 8-^. 121pp. 16 pi. Price 15 cents. 110. The Paleozoic Section in the Viciuitv of Three Forks, M(mtaua, bv Albert Charles Peale. 893. 8". 56 pp. 6 pi. Price 10 cents. 111. (Jenlogy of the Big Stone Gap Coal Fields of Virginia aud Keutuckv, bv ilarins R. Camp- bell. 18!";. 8.''lC6]ip. 6'pl. Price 15 cents. 112. Earthquakes in California in 1892, by Charles D. Perrine. 1893. 8-^. 57 pp. Price 10 cents. 113. A Report of Work done iu the Division of Cheniistrv during the Fiscal Years 1891-'92 and 1892-'93. F. W. Clarke, Chief Chemi.'it. 189.3. 8-'. 115 pp. Price 15 cents. 114. Earthquakes iu California iu 1893. by Charles D. Perrine. 1894. 8-. 1^3 jiu. Price 5 cents. 115. A Geographic Dictionary of Rhode Island, by Henry Gaunett. 1894. 8-. 31pp. Price 5 cents. 116. A Geographic Dictionary of Massachusetts, by Henry (Januett. 1894. 8-. 126 pp. Price 15 cents. 117. A Geographic Dictionary of Counecticut, by Henry Gannett. 1894. 8-^. 67 pp. Price 10 cents. 118. A Geographic Dictionary of New .Jersey, by Henry Gannett. 1894. 8^. 131 pp. Prii'c lo cents. 119. A Geological Recounoissance iu Xorthwest Wyoming, by George Homans Kldridge. 1894. 8°. 72 pp. Price lo cents. 120. The Devonian System of Eastern Pennyslvania ami New York, by Charles .S Prosser. 1894. 8-. 81pp. 2 pi. Price 10 cents. 121. A Bil>liography of North American Paleontology, by Charles Rollin Keyes. 1894. 8-. 251 pp. Price 20 cents. 122. Results of Primary Triangnlatiou, by Henry Gaunett. 1894. 8^. 412 pp. 17 pi. Price 25 cents. 123. A Dictionary of Geographic Positions, by Henry Gannett. 1895. 8-. 183 pji. 1 ]il. Price 15 cents. 124. Revision of North American Fossil Cockroaches, by Samuel Ilubbnrd Scudder. 1895. 8^. 176 pj). 12 pi. I'rice 15 cents. 125. The Constitution of the Silicates, by Frank AViggleswortb Clarke. 1895. 8-=. 109 pp. Price 15 cents. 126. A Mineralogical Lexicon of Franklin, Hampshire, and Hampden counties. Massachusetts, by Beuiamin Keudall Emerson. 1895. 8^. 180 pp. 1 pi. Price 15 cents. 127. Catalogue and Index of Contributions to North .-Vmericau Geologv, 1732-1891, bv Nelson Horatio Dartou. 1896. 8-. 1045 pp. Price 60 cents. 128. Tiie Bear River Formation and its Characteristic Fauna, by Charles A. White. 1895. 8-^. 108 pp. 11 pi. Price 15 cents. 129. Earthquakes iu California in 1894, by Charles D. Perrine. 1895. 8-^. 25 pp. Price 5 cents. 130. Bibliography and Index of Nortli American Geology, Paleoutologv, Petrology, and Miner- alogy for 1892 and 1893, by Freil I'.onghton Weeks. 1896. 8. 210 pp. Price 20 ceuts.' 131. Report of I'rogress of the Division of Hydrography for the Calendar Years 1893 aud 1894, by Frederick Hayuea Newell, Topographer in Charge. 1895. 8^. 126 pp. Price 15 cents. 132. The Disseminated Lead Ores of Sontheastern Jlissouri, by Arthur Wiuslow. 1896. S''. 31 pp. Price 5 cents. 1.33. Contributions to the Cretaceous Paleontology of the Pacific Coast: The Fauna of the Knoxville Beds, by T.W. Stanton. 1895. 8^. 132 pp. 20 pi. Price 15 cents. 131. 'i'he Cambrian Rocks of Pennsylvania, by Charles Doolittle Walcott. 1896. 8*^. 43 pp. 15 pi. Price 5 cents. 135. Bibliography and Index of North American Gecdog.y, Paleontology, Petrology, and Miner- alogy for the Year 1894, by F. B. Weeks. 1896. 8'='. 141 pp. Price 15 cents. 136. \'olcaiiic Rocks of South Mountain, Pennsylvania, by Florence Bilscom. 1896. S'-".. 121 ]i]i. 28 pi. Price 15 ( i-nts. 137. The (ieologv of the Fort Riley Military Reservation and Vicinity. Kansas, bv Robert Hay. 1896. 8^. 35 ]ip. 8 pi. Price 5 cents. 138. Artesiau-Well Prospects iu the Atlantic Coastal Plain Region, by N. H. Dartou. 1896. 8~' 22X pj). 19 id. Price 20 cents. 139. Geology of the Castle Mountain Mining District, Montaua, by W. H. Weed and L. V. Pirs- son. 1896. 8-. lfit]ip. 17 pi. Price 15 cents. 140. Ri'port of Progress of the Divisiim of Hydrography fur the Calendar Year 1895, by Frederick Ilavncs >'e'.>"i 11, : !ydnigr:nilicr in Cliar.'e. l.S9i;. H . iTi'l n:'. Pi i'e 25 ceuts. ADVERTISEMENT. VII "141. The Eocene Deposits of the Middle Atlantic Slope in DeliUTare, Maryland, and Virginia, Ijy William Bullock Clark. isy6. 8-. 167 pp. 40 pi. Price 15 cents. 142. A Brief Contribution to the Geology and Paleontology of Xorthwestern Louisiana, liv T. Wayland Vaughan. 18i^6. 8^'. C.> jip. 4 pi. Price 10 cents. 143. A Bibliography of Clays and the Ceramic Ai'ts, by .John C. Branner. 1896. 8^'. 114 pp. Price 15 cents. 144. The Moraines of the Missouri Coteau and their Attendant Deposits, by .James Edward Todd. 1896. 8^. 71pp. 21 pi. Price 10 cents. 145. The Potomac Formation in A'irginia, by W. M. Fontaine. 1896. S'-'. 149 pp. 2 pi. Price 15 cents. 146. Bibliography and Index of North American Geology, Paleontology, Petrologr, and Miner- alogy for the Year 1895, by F. B. Weeks. 1896. S-. 130 ]ip. 'Price 15 cents'. 147. Earthquakes in California in 1895, by Charles D. Perrine,x\ssistant Astronomer iu Ch.arge of Earthquake Observations at the Lick Observatory. 1896. 8'-. 23 pp. Price 5 cents. 148. Analyses of Rocks, with a Chapter on Analvtical Methods, Laboratory of the United States Geological Survey, 1880 to 1896, by F. "\V. Clarke and W. F. Hillebrand. 1897". 8^\ 306 pp. Price :lV ceuxs. 149. Bibliography and Index of North American Geology, Paleontology, Petrology, and Miner- alogy for the Ye.'ir 1!S96, by Fri-d Bough ton Weeks. 1897. 8°. 152 pp. Price 15 cents. 1.50. Tlie Educational Series of Rock Specimens collected and distributed by the United States Geological Survey, by .'osepli Silas Diller. 1898. 8"^. 398 pp. 47 pi. Price 25 cents. 151. The Lo\v<-r Cretaceous Gryphieas of the Texas Region, by R. T. Hill and T. Wayland Vaughan. 1898. 8-. 139 pp. 25 pi. Price 15 cents. 152. A Catalogue of the Cretaceous and Tertiary Plants of North America, by F. H. Kuowlton. 1898. 8=. 247 Tip. Price 20 cents. 153. A Bibliographic Index of North American Carboniferous Invertebrates, by Stuart Weller. 1898. 8^^. 6.53 pp. Price 35 cents. 154. A Gazetteer of Kansas, by Henry Gannett. 1898. 8"^. 246 pp. 6 pi. Price 20 cents. 155. Earthquakes in California in 1896 and 1897, by Charles D. Perrine, Assistant Astronomer in Charge of Earthquake Observations at the Lick Observatory. 189>', 8-. 47 pp. Price 5 cents. 156. Bibliogra|ihy a'nd Index of North American Geology, Paleontology, Petrology, and Miner- alogy for the Year 1897, by Fred Houghton Weeks. 1898. 8"-. 130 pp. j-'rice 15 cents. 160. A Dictionary of Altitudes in the United States (Third Edition), compiled by -Henry Gannett. 1899. 8-. 775 pp. Price 40 cent?. 161. Earthquakes in California in 1898, by Charles D. Perrine, Assistant Astronomer in Charge of Earthquake Observations at the Lick Observatorj-. 1899. 8°. 31pp. 1 pi. Price 5 cents. Jn 2)repuraiioii: 157. The Gneisses, Gabbro-Schists, and Associated Rocks of Southeastern Minnesota, by C. W. Hall. 158. The Moraines of southeastern South Dakota and their Atteuaration: 29. Wells and Windmills in Nebraska, by Edwin H. Barbour. 30. Water Resources of the Lower Peninsula of Michigan, by Alfred C. Lane. TOPOGRAPHIC MAP OF THE UNITED STATES. AVhen, in 1882, the Geological Survey was directed by law to make a geologic map of the United States there was in existence no suitable topographic map to serve as a base for the geologic map. The preparation of such a topographic map was therefore immediately beguu. About one-fifth of the area of the country, excluding Alaska, has now been thus mapped. The map is published in atlas sheets, each sheet' representing a small quadrangular district, as explained under the next head- ing. The separate sheets are sold at 5 cents each when fewer than 100 copies are purchased, but when they are ordered in lots of 100 or more copies, whether of the same sheet or of different sheets, the price is 2 cents each. The mapped areas are widely scattered, nearly every State being represeuted. About 900 sheets have been engraved and printed; they are tabulated by States in the Survey's •'List of Publications," a pamphlet which may be had on application. The map sheets represent a great variety of topographic features, and with the aid of descriptive text they can be used to illustrate topographic forms. This has led to the projection ot an educational series of topographic folios, for use wherever geography is taught in high schools, academies, and colleges. Of this series the first folio has been issued, viz : 1. Physiographic types, by Henry Gannett, 1898, folio, consisting of the following sheets and 4 pages of descriptive text: Fargo(N. Dak.-Minn.), a region in youth ; Charleston (W.Va.),a region in maturity; Caldwell (Kans.), aregion in old age; Palmyra (Va.), a rejuvenated region; Mount Shasta, (Cal.), a young volcanic mountain; Eagle (Wis.), moraines; Sun Prairie (Wis.), drumlins; Douald- sonville (La.), river flood plaius; Boothbay (Me.), a fiord coast; Atlantic City (N. J.), a barrier-beach GEOLOGIC ATLAS OF THE UNITED STATES. The Geologic Atlas of the United States is the final form of publication of the topographic and geologic maps. The atlas is issued in parts, progressively as the surveys are extended, and is designed ultimately to cover the entire country. Under the plan adopted the entire area of the country is divided into small rectangular districts (designated qnadrangUs), bounded by certain meridians and parallels. The unit of survey is also the unit of publication, and the maps and descriptions of each rectangular district are issued as a folio of the Geologic Atlas. Each folio contains topographic, geologic, economic, and structural maps, together with te.xtual descriptions and explanations, and is designated by the name of a principal town or of a prominent natural feature within tlie di.strict. Two forms of issue have been adopted, a "library edition" and a "field edition." In both the sheets are bound between heavy paper covers, but the library copies are jiermanently bound, while the sheets and covers of the field copies are only temporarily wired together. Under tiie law a copy of each folio is sent to certain public liiiraries and educational institu- tions. The vciuainder are sold at 25 cents oacli, except such as contain an nuusual amount of matter, which are priced accordingly. Prepayment is obligatory. The folios ready for distribution are listed below. No. Nunie of shoot. State. Livingston Montana.. _,. ,, fdi'orgia-.- lt"'i'i!0''l ClViim-ssec Vlacorville Kingston Sacramento Clialtanooga I'ikes Pcalt (outot'stoclt). Sewanee AnHiracitc-Crcstcd Butte Harpers yerrj- . C'alil'oriiia. . Tennessci; . California. . Tfancsseo . Colorado Tennessee . Colorado. Limiting meridians. (Virginia West Virginii l^Iarylaud 1100-111° 850-85° 30' 120° 30'-121° 81° 31l'-85o 1210-121° 30' 85°-85° 30' 1050-1050 30' 85° 30'-8C° 106° 45'-107o 13' 770 30'-78° Limiting parallels. 45°-16o 340 30'-3So 38° 30'-30O 33° 30' -360 38° 30'-39' 35°-35° 30' 38° 30'-39° 35°-350 30' 38° 45'-390 390-30° 30' Area, in Price, sq iiaro in miles. cents. 3,354 25 980 25 932 25 969 23 932 25 975 25 932 25 975 25 465 50 925 25 ADVERTISEMENT. IX No. 29 30 Name of sheet. Jackson . . Estillville . Fredericksburg. Staunton Lassen Peak KnoxTille , Marysville.. Smartsville . Stevenson . . Cleveland Pikeville McMiuDville. Nomini Three Forks . Loudon Pocahontas . . . Morriatown... Piedmont Nevada City. [Nevada City . ] < Grass Valley. } (Banner Hill .J fGallatin . . Na- ICiinyon-. . [Shoshone. [Lake /Tellowstone \ tional Park. Pyramid Teak . Franklin Briceville Buckhannon Gadsden Pueblo Downieville Butte Special Truckee "Wartbnrg Sonora Nueces Bidwell Bar Tazewell Boise Kichmond London Tenmile District Special. Roseburg Holyoke California. {Virginia .. Kentucky. Tennessee f Maryland . \Virginia . . ^Virginia .. (West Virginia.. California J Tennessee INorth Carolina California California {Alabama Georgia Tennessee Tennessee Tennessee Tennessee /Maryland \Virginia Montana Tennessee (Virginia \West Virginia . Tennessee {Virginia ... Maryland West Virginia.. California . Limiting meridians. "Wyoming . California /Virginia IWest Virginia . Tennessee West Virginia . Alabama Colorado California Montana California Tennessee California Texas California /Virginia \West Virginia.. Idaho Kentucky Kentucky Colorado Oregon /Massachusetts . IConnecticut 121° 00' 121° 01' 20° 57' (12 12: (]2I 120° 30'-121° 82" 30'-8a° 770.770 30' 790-790 30' 121°-1220 83° 30'-84° 121° 30'-122o 121°-121o 30' 35° 30'-86° 84° 30'-85° 85°-85as30' 85° 30'-86° 76° 30'-77° 111°-112° 84°-81° 30' 810-81° 30' 830-83° 30' 790-790 30' 25"-1210 03' 45" 35"-121° 05' 04" 05"-121o 00' 25" 120°-120° 30' 790-790 30' 84°-84o 30' 80°-80o 30' 860-86° 30' 104° 30'-105o 120° 30'-121° 30"-112° 36' 42" 1200-120° 30' 84° 30'-85o 120°-120° 30' 100°-100o 30' 121°-121° 30' 81° 30'-82° 116°-1160 30' 840-810 30' 840-840 30' IO60 8'-106o 16' I230-I230 30' 720 30'-73o Limiting parallels. 38°-38° 30' 36° 30'-37° 38''-38° 30' 380-38° 30' 40O-41O 35° 30'-36° 390-39° 30' 390-390 30' 340 30'-35° 350-350 30' 350 30'-36o 350 30'-36o 380-38° 30' 45°-46° 350 30'-36o 370-370 30' 360-360 30' 390 13' 50"-39° 17' 16" 39° 10' 22"-39° 13' 60" 39° 13' 50"-39° 17' 16" 450 59' 28' 38° 30'-39° 38° 30'-39o 360-36° 30' 380 30'-39° 34°-340 30' 380-380 30' 390 SO'^Oo '-46° 02' 54," 390-390 30' 360-360 30' 370 30'-38o 29° 30'-30° 39° 30'-40° 370-370 30' 430 30'^4o 370 30'-38° 37°-37° 30' -39° 30' 30" 43°-430 30' 420-42° 30' Area, in square miles. 933 957 938 938 3,634 925 925 925 975 969 969 3,354 969 951 963 11.65 12.09 11.65 932 963 932 980 938 919 22.80 925 963 944 1,035 918 950 ■ 864 944 950 55 871 Price, in cents. 25 25 25 25 25 25 25 25 25 25 50 25 23 25 25 25 25 25 25 50 25 50 25 25 25 25 25 25 25 25 25 25 STATISTICAL PAPERS. MineralKesourcesof the United States [1882], by Albert Williams, jr. 1883. 8°. xvii,813pp. i riC6 OU C611XS. ,n, . Mineral Resources of the United States, 1883 and 1884, by Albert Williams, jr. 1885. 8° siv 101b pp. Price 60 cents. ' ' IMC MmeralResources of the United States, 1885. Division of Mining Statistics and Technology. 1886. 8°. VII, o76pp. Price 40 cents. °'' Mineral Resources of the United States, 1886, by David T. Day. 1887. 8°. viii, 813 pp Price 60 cents. ' ■^■■ Mineral Resources of the United States, 1887, by David T. Day. 1888. 8°. vii, 832 pp. Price Mineral Resources of the United States, 1888, by David T. Day. 1890. 8°. vii, 652 vv Price 50 cents. ? 1 1 MiueralResourcesof the United States, 1889 and 1890, by David T.Day. 1892 8° viii 671 nn Price oO cents. " ' ' '^'^' Mineral Resources of the United States, 1891, by David T. Day. 1893. 8°. vii. 630 pp. Price 0\} cents. ' X • ADVERTISEMENT. Mineral Resonrres ublications is deposited in the Treasury, and the Secretary of that Department declines to receive bank checks, drafts, or postage stamps ; all remit- tances, therefore, nuist be by money order, made payable to the Director of the United .States Geological Survey, or in currency — the exact amount. Correspondence relating to the publications of the Survey should be addresseil to The DiREciiii:. Uniteh States Geological Scrvey, Washington, 1). C, June, 1S99. "Washington, D. C. [Take tliis leaf out and paste the separated titles upon three of your cata- logue cards. TLe lirst and second titles need no addition ; over the third "write that subject under which you would place, the book in your library.] LIBRARY CATALOGUE SLIPS. TJmted States. Vepartment of ilie interior. ( U. S. geological survey,} Deiiartment of the interior | — | Monographs | of the | United States geological survey | Volume XXXVIII | [Seal of the depart- ment] I Washington | government printing office | 1899 Second title: United States geologiiJal snrvej' | Charles D. Walcott, director | — | The | Illinois glacial lobe | hy | Frank Leverett | [Vignette] | Washington | government printing olBce | 1899 4°. ixi, 817 pp. 24 pi. Leverett (Frank). United States geological survey | Charles T>. Walcott, di- rector I — I The I Illinois glacial lohe | by | Frank Leverett | [Vignette] | Washington | government printing office | 1899 4°. xxl, 817 pp. 24 pi. [United States. DeparUnent of the interior. {U. S. geological survey.} Monograph SXXVIII.] United States geological survey | Charles D. Walcott, di- rector I — I The I Illinois glacial lobe | by | Frank Leverett | [Vignette] | Washington | government printing office | 1899 4°. xxi, 817 pp. 24 pi. [United States. Departrnent of the interior. ( Vf. S. geological survey.) Monograph XXXVIII.]