Cop \(p c.3 STATE OF ILLINOIS STATE GEOLOGICAL SURVEY FRANK W. DE WOLF, Director Cooperative Goal Mining Series BULLETIN 16 GOAL RESOURCES OF DISTRICT II (Jackson County) BY GILBERT H. CADY Field work by G. H. Cady, F. H. Kay, K. D. WLite, and others ILLINOIS GOAL MINING INVESTIGATIONS Trepared under a cooperative agreement between the Illinois State Geological Survey, the Engineering Experiment Station of the University of Illinois, and the U. Sv Bureau of Mines. PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS ILLINOIS STATE GEOLOGICAL SURVEY UNIVERSITY OF ILLINOIS URBANA 1917 The Forty-seventh General Assembly of the State of Illinoi with a view of conserving the lives of the mine workers and the mil eral resources of the State, authorized an investigation of the co resources and mining practices of Illinois by the Department of Mil ing Engineering of the University of Illinois and the State Geologic Survey in cooperation with the United States Bureau of Mines, cooperative agreement was approved by the Secretary of the Interi< and by representatives of the State of Illinois. The direction of this investigation is vested in the Director of tl United States Bureau of Mines, the Director of the State Geologic Survey, and the Director, Engineering Experiment Station, Un versity of Illinois, who jointly determined the methods to be en ployed in the conduct of the work and exercise general editorial supe vision over the publication of the results, but each party to the agre ment directs the work of its agents in carrying on the investigatk thus mutually agreed on. The reports of the investigation are issued in the form of bull tins, either by the State Geological Survey, the Engineering Experime: Station, University of Illinois, or the United States Bureau of Mine ^For copies of the bulletins issued by the State Geological Surve address State Geological Survey, Urbana, Illinois; for those issu< by the Engineering Station, address Engineering Station, Universi of Illinois, Urbana, Illinois ; and for those issued by the U. S. Bure< of Mines, address Director, U. S. Bureau of Mines, Washington, D. ' (See list at end of book.) ILLINOIS STATE GEOLOGICAL SURVEY 3 3051 00006 4166 STATE OF ILLINOIS STATE GEOLOGICAL SURVEY FRANK W. DE WOLF. Director Cooperative Coal Mining Series BULLETIN 16 GOAL RESOURCES OF DISTRICT II (Jackson County) BY GILBERT II. GADY Field work by O. Il.Ciuly, F. II. Kay, K. I). White, and others ILLINOIS GOAL. MINING INVESTIGATIONS Prepared under a cooperative agreemenl between the Illinois State Geological Sun the Engineering Experiment Station of the Universitj of Illinois, and tin- I '. S. Bureau of Mines. PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS ILLINOIS STATK GEOLOGICAL SURVEY UNIVERSITY OF ILLINOIS URBANA 1«>I7 A CONTENTS PAGE Chapter I — Introduction 11 Economic importance of area 11 Acknowledgments 11 Chapter II — Geography 13 Location 13 Topography 13 Glaciation 14 Drainage 15 Towns and railroads 15 Chapter III — General geology 17 Stratigraphy 17 Pennsylvanian series ("Coal Measures") 17 General features 17 Pottsville formation 17 Carbondale formation 19 Thickness 19 Lithologic characteristics 19 Correlation 20 Coal Xo. 2 20 Vergennes sandstone member 21 Strata between Vergennes sandstone and coal No. 5.... 22 Coal No. 5 and associated strata 23 Coal No. 6 and underclay 24 McLeansboro formation 24 General character 24 Shale and limestone overlying coal Xo. 6 24 Strata above limestone cap rock 25 Quaternary system 26 Pleistocene series 26 Glacial till 26 Valley fill 26 Structure 28 Method of showing structure 28 Reliability of structure contours 28 Uses of the structure map 29 Structure of District II 30 General features 30 Details of structure 30 Chapter IV — Economic geology of the coals 33 Pottsville coals 33 Carbondale coals 33 Coal No. 2 33 Distribution and thickness 33 Physical characteristics 36 Detailed observations 37 Quality of coal Xo. 2 44 (5) CONTENTS— Continued Roof 44 Floor 45 Structural irregularities 46 Coking qualities 49 Coals between coal No. 2 and coal No. 6 49 Coal No. 5 49 Minor coal beds 51 Coal No. 6 51 (6) ILLUSTRATIONS PLATE PAGE I. Map of District II showing locations of mines, drill holes, outcrops, and structure contours on coals No. 2 and No. 6 14 II. Graphic sections of borings in District II 18 III. Graphic average analyses of Illinois coals by beds 44 FIGURE 1. Map showing area of District II as covered by this report 10 2. Sketch map showing terraces along Big Muddy River and its tribu- taries 14 3. East-west section across the Murphysboro and Herrin quadrangles in Jackson County 32 4. North-south section across the fault in Jackson County 32 5. Diagrammatic illustration showing the thickening of the parting in Harrison mine, Big Muddy Coal and Iron Company 36 6. Graphic sections of coal No. 2 in Jackson County 38 7. Shale in pit of Murphysboro Paving Brick Company 45 8. Diagrammatic illustration of a fault, slip, and horseback in mine No. 2, Gus Blair Big Muddy Coal Company 40 9. Diagrammatic illustration of a horseback in mine No. 9, Big Muddy Coal and Iron Company 46 10. Diagrammatic illustration showing a slip without displacement, mine No. 9, Big Muddy Coal and Iron Company 47 11. Diagrammatic illustration of a horse in Harrison mine. Big Muddy Coal and I ron Company 47 12. Diagrammatic illustration of a roll in mine No. 9, Big Muddy Coal and 1 ron Company 48 13. Graphic sections of coal No. 6 in Jackson County 50 (7) Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/coalresourcesofd16cady TABLES PACK 1. Recorded thicknesses of the drift in drill holes in Jackson County. ... 27 2. Thicknesses of coal Xo. 2 in District II 34 3. Thicknesses of coal Xo. 2 and character and thickness of roof and floor in mines of District II 40 4. Analyses of mine samples of coal from District II 42 5. Average analyses of Illinois coals by districts 43 6. List of shipping mines in District II (Jackson County), 1915 53 (9) MAP OF ILLINOIS Fig. 1. — Map showing area of District II as covered by this report. (10) GOAL RESOURCES OF DISTRICT II By G. H. Gady CHAPTER I— INTRODUCTION Economic Importance of Area District II of the Illinois Coal Mining Investigations includes that part of Jackson County (fig. 1) underlain by coal No. 2 (Murphys- boro coal). This district, the smallest in the State, has the distinction of furnishing coal of highest calorific value for Illinois ; as the area underlain by workable coal is restricted there are but few mines, so that the production from District II is comparatively small. A total output from 6 shipping mines for the year ending June, 1916, was 625,964 tons. The northeastern part of Jackson County is underlain also by two other beds of coal, No. 5 or Harrisburg and No. 6 or Herrin, the upper one of which is being mined at a number of places ; but both arc of commercial value. Acknowledgments The description of the coal resources of District 11, which con- stitutes the subject matter of this bulletin, is based upon field investi- gations by members of the State Geological Survey and L T . S. Geol- ogical Survey, upon the text and maps of the Murphysboro-Herrin folio of the Ceologic Atlas of the U. S. Geological Survey, by E. \Y. Shaw and T. E. Savage, which has been largely drawn upon, and upon the tabulation and study of data derived from about 180 drilling records furnished the State Geological Survey by various companies operating in the district. Special acknowledgment is made of the use of field notes of Messrs. K. D. White and F. II. Kay, collected in 5 mines selected for examination by the Investigations. Thanks are due to the operators of the district for information furnished the Survey and for kindly cooperation in opening the mines to examination. The bulletin is one of a series of similar publications prepared by the State Geological Survey in cooperation with the Mining Experi- ment Station of the University of Illinois and the U. S. Bureau of Mines, dealing with the coal resources of the various districts of the State. The districts examined by the Investigations are listed in the Preliminary Bulletin, Illinois Coal Mining Investigations. (11) CHAPTER II— GEOGRAPHY Location District II lies entirely within the boundaries of Jackson County, but is not coextensive with the county. The north and east boundaries of the district coincide with the boundaries of the county. The boundary to the southwest is marked by the outcrop of coal No. 2 along an irregular and more or less indefinite line running north from a point about 5 miles west of Murphysboro and southeast toward Carbondale. Small outliers of coal Xo. 2 lie to the west between the main line of outcrop and the bluff of the Mississippi, the most import- ant of which is in the vicinity of Ava. District II lies south of District YII and west of District VI, as defined by the Cooperative Investigations. The most important por- tion of the district lies in the vicinity of Murphysboro within the boundaries of the Murphysboro and Herrin quadrangles, the geological report upon which has already been published. 3 Topography The Murphysboro and Herrin quadrangles exhibit two types of topography, according to Shaw and Savage — the higher hills bordering the Mississippi and the interior lowlands. District II lies almost wholly within the interior lowlands, only the western part near the outcrop of coal Xo. 2 being in the hilly portion of the county. The interior lowlands have an altitude of about 400 to 480 feet, whereas the altitude of the hilly country south of Ava reaches 720 feet. West of the district and beyond the outcrop of coal Xo. 2 the county is under- lain largely by the resistant Pottsville sandstone. The highest hills here reach an elevation of about 750 feet. The interior lowlands have been described as follows: 2 The principal features of the interior plain are (1) the low hills; (2) the slightly rolling divides 420 to 460 feet above sea level; (3) the broad terraces along the principal streams, lying for the most part at 390 to 410 feet; (4) the flood plains, at 360 to 385 feet; and (5) the deep river and creek channels cut 20 feet or more below the flood plains. On each stream the terraces, flood plain, bottom of the channel, and surface of the bed rock below the channel all converge upstream. The terraces are the upper surfaces of valley deposits which attain a maximum thickness of about 110 feet along the courses of the rivers. The terraces seem to have been formed by the deposition of material by temporarily obstructed streams that once emptied into the Mississippi at a level considerably below that of the present channels. 'Shaw, I-:. W\, and Savagfe, 'I'. E„ l T . S. Geol. Survey Geol. Atlas, Murphysboro-He folio (No. 185), 1912. -Idem, ]>. 1. (13) COAL RESOURCES OF DISTRICT II Figure 2 is a sketch map showing the area covered by these terraces bordering Big Muddy River and its tributaries and the posi- tion of District II. The map is adapted from one appearing in the Murphysboro-Herrin folio. 5 Miles Fig. 2. — Sketch map showing terraces along Big Muddy River and its tribu- taries. Glaciation Glacial deposits mantle the hill tops and many hill sides in the more elevated portions of the district, and a covering of yellow loess effects a still further concealment of the bed rock and renders the out- crops of the coal obscure. It is probable that the glacial till, if not the loess of the hilly country extends below the alluvial material of the interior lowlands, as almost all the area was covered at least once by a great ice sheet which left a continuous but a relatively thin mantle of debris which did not greatly modify the surface configuration. This region thus differs from the central and northern parts of the State, which were subjected to the erosion of moving ice for a much longer time and which received thick deposits from an oscillating ice front. Subsequent to glaciation of the region the valleys filled with silt and gravel, forming the extensive terraces now existing along the streams. S STATE GEOLOGICAL SURVEY ( QOKKATXVE AGREEMENT R.4 W. BULLETIN 16, PLATE R.3 W. R.I W. ^A2 Coal mine; number refers to Table 6 X Local mine # Drill hole Contours on coal No. 6, north - J east of the outcrop of that 5 O x coal; on coal No. 2 between s*3 v outcrops of coals No. 2 and No. 6. , . Outcrop of coal No. 6 Outcrop of coal No. 2 «__ Direction of dip of rocks * — I Railroad • Electric line County boundary Township boundary 420 Elevation of town above sea level GEOGRAPHY 15 Drainage The run-off of the district reaches the Mississippi through Big Muddy River, of which the two largest tributaries in Jackson County are Beaucoup Creek and Little Muddy River. The principal streams are, according to Shaw and Savage, 3 similar in profile and in certain other features. Each is naturally separable into three longitudinal divisions. In the first and upper division the streams are about the level of the extensive terraces, the valleys seem normal in all respects, and rock outcrops are numerous. In the second division the floodplains of the streams lie at approximately the same altitude as the terraces and accordingly the valley is broad and swampy. Here the stream flows over the unconsolidated sandy deposit, and rock outcrops are very rare. In the third division the stream lies below the terrace surface. Rock outcrops are absent except where the stream swings to one side of the valley, leaving terraces on the opposite side. The gradient is very low, the banks are of mud or fine silt, the channel is deep, and the floodplain narrow. Towns and Railroads The principal towns of the district are Murphysboro and Car- bondale, each having several thousand inhabitants. There are numer- ous smaller towns which depend for their prosperity upon the coal- mining industry, especially in the northeast part of the county east of the outcrop of No. 6 (Herrin) coal. Several railroads traverse Jack- son County, and transportation facilities are entirely adequate for the coal industry of the district. •'Idem, p. 2. CHAPTER III— GENERAL GEOLOGY Stratigraphy pennsylvanian series ("coal measures") GENERAL FEATURES The rocks of the Pennsylvania!! series contain all the known coal beds in this and the other districts of the State. The series consists of a succession of shales and sandstones, and minor amounts of lime- stone, clay, and coal. In Jackson County the greatest known thick- ness of "Coal Measures" or Pennsylvanian rocks is between 1,000 and 1.100 feet. Toward the southeastern part of the State the series attains a thickness of 2,000 feet, the greater thickness being due to the greater thickness of individual formations and to the presence of a greater amount of the upper part of the series than is found in Dis- trict II, where much material has been removed by erosion. Underlying the Pennsylvanian series are several series of forma- tions belonging to older systems. Of these the rocks of the JMissis- sippian series are comparatively well known both from drill records and from outcrops not far distant along Mississippi River. Below the Mississippian series lie the rocks of the Devonian system. About 1,300 feet of limestone encountered in the deepest drill hole represents the Devonian, Silurian, and Ordovician systems. Plate II, No. 1, presents a generalized columnar section of the Pennsylvanian rocks in Jackson County, adapted from the Murphysboro-Herrin folio. The Pennsylvanian series in Illinois lias been separated for con- venience in study into the following three formations, named in as- cending order — Pottsville, Carbondale, and McLeansboro. POTTSVILLE FORM ATI ON The upper limit of the Pottsville, which is known with fair accu- racy, lies at a very short distance below coal No. 2 (Murphysboro coal), and for convenience the base of the coal has been used by the State Geological Survey as the formation boundary. The following descrip- tion of the Pottsville formation for the Murphysboro and I lerrin quad- rangles is adequate for the entire district. 1 The Pottsville formation is composed principally of sandstone. In the southwestern portion of the area it crops out extensively with a thickness rang- ing from 420 to 510 feet, and owing to its resistant nature and its uplift it forms very rugged hills. In the northern and eastern parts of the area the Pottsville generally extends from near the base of the coal No. 2 down to the first limestone and may thus he identified in drill holes by its position. But in some places a sand- stone overlying this limestone belongs below the Pottsville, and in such places 'SI, aw, E. W., and Savage, T. E., U. S. Geol. Survey G'eol. Atlas. Murphysboro-Herrin folio (No. 185), p. 6, ]')\ 1. (17) 18 COAL RESOURCES OF DISTRICT II the base of the Pottsville is very difficult to determine, even in outcrops. The formation is generally made up of seven sandstone members separated by layers of shale, though in many places one or more shale members are absent or are represented by sandstone. In such places there appear to be fewer sandstone members. The shale generally contains some thin-bedded or lenticular sandstones and one or more carbonaceous beds or coal seams. All the strata are very irre- gular ; beds of sandstone grade laterally into shale, and hardly any bed holds its physical character throughout any considerable area. The seven main sand- stones are not very persistent and are of irregular thickness. The lowest sandstone, which, in general, is fine grained, creamy white, and relatively soft, has a maximum thickness of 60 feet though locally it seems to be absent. Above it lies 5 to 75 feet of sandy shale locally containing traces of coal. The second sandstone is 35 to 60 feet thick and the third 50 to 85 feet thick. These two sandstones are considerably more resistant than the first and contain pebbles, especially in their lowermost parts. Throughout most of the area they are separated by a bed of soft shale, ranging in thickness up to about 20 feet, with lenses of sandstone and traces of coal. The upper of the two is overlain by a more or less sandy shale, 1 to 20 feet thick, containing beds of pure sandstone. The fourth sandstone measures 45 to 85 feet and the fifth 70 to 100 feet. Both are gray, clean, and hard, and contain a few lenses of shale, and toward the top scattered pebbles. They are separated by an irregular mass of shaly sandstone, from 30 to 90 feet thick, containing lenses of soft shale, and having at the top a fairly persistent coal bed, 2 to 25 inches thick. The fifth sand- stone is overlain by 1 to 40 feet of shale and shaly sandstone. The sixth sandstone is 40 to 80 feet thick and the seventh 20 to 35 feet. Both are conglomeratic, particularly northeast of Ava. The pebbles seem to be concentrated along bedding planes and not scattered irregularly through the mass. The shale with shaly sandstone, between these uppermost sandstones is irregular in thickness, ranging from 3 to 30 feet, and contains one or more lenticula'r coal beds and commonly masses of iron oxide. At least a part of this shale member is of Mercer age. Near Oraville and on the Mississippi bluffs little conglomerate appears in any layer of the Pottsville, but in other places, as near Sugar Hill school, quartz pebbles are scattered through much of the formation. Between the uppermost sandstone and coal No. 2 there is a 10 to 30 foot shale member with local sandstone layers. On Plate II are five graphic sections (Nos. 2 to 6) of drilling records of coal or oil borings in Jackson County which show the char- acter of the Pottsville formation. It will doubtless be observed that the seven sandstone members of the Pottsville formation described above are not distinguishable in any of these records. Their relative position and thickness, however, is indicated in the generalized section ( I Mate IT, No. 1 ). In general the lithologic criteria for the identifica- tion of the several sandstone members of the Pottsville formation are of little practical value. In most drill records the base of the Pottsville is placed at the first limestone below the main coal beds and below a considerable thickness of sandstone. The base of the formation is MISSISSIPPIAN PENNSYLVANIAN Chester Pottsville Carbondale McLeansboro y / I mm Ffffflf wrap. 41 .•■! ' ^vl :^;ij;;fe!: B— H T.7 S..R.1 W.tO I e ■ o ■fill 8 £ J I a > z I (0 \ / / / m WiWiWi / SMI! T.8 S..R.1 W. CO la g / / / / 3) to to r Q i (0 w 3 Q. (A g s 3 S m z iiiiiiii 1 m T.8 S..R.2 W. ^ CD CD \ If \ FMTTI WrWrW m'l'i'iWi'i \ m ililiiii T.8 S..R.2 W. 01 CD / I / ! g / an ^nflUfe^iBi si I II T.8 S..R.2 W. Ci § § § V£ffr S H > w < a £ ° g r 2 o s ° s g en a GENERAL GEOLOGY 19 undeterminable where the upper formation of the Mississippian series is sandstone or shale ; the top is difficult to determine where coal No. 2 is absent. The coal beds of the Pottsville formation are of no commercial importance. A thin seam 12 inches or less in thickness is not uncom- mon about 75 feet below the top of the formation (coal No. 2), and some records note a thin bed of 3 or 4 inches about 40 feet below coal No. 2. Otherwise the formation seems to be barren. CARBONDALE FORMATION Thickness. — The Carbondale formation includes all the strata from the base of coal No. 2 to the top of coal No. 6 (Herrin coal). The name is taken from the town of Carbondale, Illinois, in the vicin- ity of which the formation is well exposed. The formation in Jack- son County attains a thickness of 254 feet in at least one locality. LitJwlogic characteristics. — The formation between coal No. 2 at the base and coal No. 6 at the top of the formation is made up largely of shale and sandstone with several thin layers of limestone and more or less lenticular beds of coal. The shale, which is poorly laminated and claylike, ranges in color from black to dark gray. The sandstone is commonly loosely cemented and rather micaceous, though one or two of the thinner beds are firmly cemented by calcium carbonate. The limestone is hard, gray to bluish gray, and more or less fossiliferous. Some of it has a peculiar brecciated or conglomeratic appearance. The sequence of the beds composing the formation may be seen in the generalized columnar section on Plate II. No. 1. The succession as found in a coal prospect located in this area is recorded below. This record is reproduced graphically as section No. 2, I Mate II. The graphic reproduction includes also part of the adjacent formation above and below and represents the entire log. Partial record of a drilling showing flic character of I he Carbondale formation (Sec Plate II, No. 2) Description of strata Thickness Depth Coal (Herrin or Xo. 6) Ft. .. ' 8 1 6 14 3 4 4 58 1 in. 6 6 6 Ft. 158 159 165 179 182 186 191 249 250 in. Underclay Limestone Shale Limestone "Slate," black 6 Coal (Harrisburg or Xo. Shale 5) 1 limestone 20 COAL RESOURCES OF DISTRICT II Partial record of a drilling showing the character of the Carbondale formation Concluded Description of strata Thickness Depth Shale, black Coal (No. 4?) Underclay Shale, sandy Sandstone Shale Limestone "Slate," black Coal (No. 3?) Underclay Shale, sandy . Sandstone Shale Coal (Murphysboro or No. 2?) Shale Coal (Murphysboro or No. 2?) Ft. in. 3 6 2 10 6 22 25 10 1 3 6 2 6 5 23 24 6 1 . 10 20 2 2 3 in. 6 6 Correlation. — The following is quoted from the Murphy sboro- Herrin folio : 2 From a study of the fossil plants found in the coal seams and associated strata in the State, David White concludes that the Murphysboro coal is the lowest coal bed in Illinois that falls within the time interval of the Allegheny formation of Pennsylvania. He also concludes that the Herrin coal may be of Freeport age, possibly as high in the stratigraphic column as the Upper Freeport coal, which is the uppermost layer of the Allegheny formation in the Appalachian region. From these correlations it will be seen that the Car- bondale formation corresponds in a general way to the Allegheny formation of the Appalachian region. Coal No. 2 is believed to be of about the same age as the La Salle (No. 2) coal of District I of northern Illinois. Coal No. 2. — The Murphysboro (No. 2) coal ranges in thickness from 1 to 6 feet or more and is commonly divided into two or more benches. The bed is of somewhat irregular thickness and seems to be absent from considerable area in the northern and eastern parts of the quadrangle. It is also absent throughout most of the hills, whence it has been removed by erosion, but it is workable almost con- tinuously along the foot of the hills. The bed is mined extensively in the vicinity of Murphysboro, and has also been mined V/2 miles north- west of Oraville, at Bryden, at Sato, and at points V/2 miles south of Ava, and 2 l / 2 miles southwest of Matthews. At these places the bed is somewhat variable, but there is generally 3 to 4 feet of excellent coal. GENERAL GEOLOGY 21 In the vicinity of Murphysboro and along the outcrop of coal No. 2 near Sato, the coal occurs in considerable areas as an unbroken seam. The margin of this especially valuable coal is marked either by the out- crop or by a splitting up of the seam by beds of shale of increasing thickness. These irregularities may occur at any place in the bed or at several places at once, but it possibly is found to take place most commonly near the middle of the seam. The rapid variation in thick- ness of the two benches of coal Xo. 2 and of the shale parting is illus- trated by the following drilling records of borings located in the same section. Lower part of the Carbondale formation at the cast side of the SE. T 4 SW. ' 4 sec. 32, T. 8 S., R. 2 W. Thickness Ft. Loess and valley filling 30 Carbondale formation — Shale, yellow clay 10 Shale, hard, blue v 2 8 5 Coal Shale .... Coal Coal, bony Clav Coal No. 2 m. 7 9 6 2 w 5-M 6 2Ya Lower part of Carbondale formation at the west see. 32, T. S S., R. 2 \\ ride of the SE. Sll Thickness Ft. in Loess and filling $1 I ( Carbondale formation — Shale, yellow, soft 5 Shale, blue .11 Shale, black Coal Coal, bony Shale, blue Coal Shale, blue Shale, dark, calcareous Sandstone, hard Vergennes sandstone member. — The following description is given by Shaw and Savage: 2 The Murphysboro coal is generally overlain by a seam of clay ("sheep skin"), which is in turn overlain by 20 to 40 feet of shale or in a few places shaly sandstone, which where thickest locally contains a thin coal seam near the middle. This shale is in turn overlain by sandstone or in some places by sandy 'lllrlll, p. 6. 22 COAL RESOURCES OF DISTRICT II shale, which seems to be persistent though irregular in thickness, ranging from 15 to 45 feet. This sandy member is micaceous, loose, friable, and brownish. Although it is not nearly so resistant as tne beds of the Pottsville sandstone, it forms low hills, and 4 miles northwest of Vergennes, in sec. 11, T. 7 S., R. 3 W., it is well exposed on a large hill. The persistent nature of this rock and its importance as a key stratum (as it forms low hills and crops out more exten- sively than other parts of the Carbondale formation) seems to warrant a special name, and the term Vergennes sandstone member is here proposed. Strata between Vergennes sandstone member and coal No. 5. — In the folio covering the Murphysboro and Herrin quadrangles is the following description. 3 Above the Vergennes sandstone member is a bed of clay 5 to 6 feet thick, and overlying the clay and about 55 feet above coal No. 2 there is a persistent coal bed, 6 to 28 inches thick. This coal, which is thin in the northern part of the area and thickens toward the south, is exposed at the surface in the east bank of Crab Orchard Creek, near the northwest corner of sec. 36, T. 8 S., R. 1 W., where it has been mined by drifting. The following section was made at this place : Section exposed in sec. 36, T. 8 S., R. 1 W . Thickness Ft. in. 5. Sandstone, yellowish-brown, marked with numerous small brown spots 4 6 4. Limestone, argillaceous, single bed 1 4 3. Shale, black, fissile 2 8 2. Coal 2 1. Underclay, gray 1 6 Eight rods north of this exposure 12 feet of sandstone is laid bare in the bank of the creek. One-fourth mile up the creek from the latter point 10 feet of the sandstone overlain by 6 feet of gray sandy shale is exposed. At the east end of the wagon bridge over Crab Orchard Creek, near the middle of the north half of sec. 2, T. 9 S., R. 1 W., the following succession of strata is exposed : Section exposed in sec. 2, T. 9 S., R. 1 IV. Thickness Ft. in. 8. Limestone, argillaceous, somewhat concretionary 1 7. Shale, black, fissile, containing Orbicnloidea niissonri- ensis and dermal tubercles of Petrodus occidentalis. 3 6. Coal 2 4 5. Underclay, gray 2 6 4. Shale, gray 5 6 3. Shale, gray, sandy 7 2. Sandstone, yellowish gray 8 1. Sandstone, fine grained, shaly 10 In the above section the beds numbered 5 to 8 inclusive are the equiva- lents respectively of those numbered 1 to 4 in the preceding section. Corre- • ! Idem, p. 7. GENERAL GEOLOGY 23 sponding beds outcrop about a mile southeast of the bridge over Crab Orchard Creek, in sec. 1 of the same township, where the coal has been stripped for local use. The sandstone bed at this last place, overlying the 1-foot limestone above the coal seam, is 16 feet thick. In a ravine about half a mile north of this point 14 feet of the sandstone, succeeded by 5 feet of shale, is exposed. In some records the sandstone is reported to be about 25 feet thick. The strata described represent the beds associated with the coal lying about 55 feet above coal No. 2. The sandstone member above the coal is suc- ceeded by a bed of shale 40 to 50 feet thick, commonly more or less sandy and locally a true sandstone. In some places, as 2 miles southeast of Denmark, the central part of this shale contains calcareous and fossiliferous layers of sand- stone. * * * . Above the shale is a bed of clay 5 to 6 feet thick, which is in turn overlain by a 2-foot bed of coal. This coal lies about 80 feet above the coal referred to in the preceding paragraph and 135 feet above coal No. 2. It is overlain by a bed of black, finely laminated shale 3 to 5 feet thick, upon which rests a 1-foot layer of limestone. Above the limestone 40 feet or more of gray shale, locally fossiliferous in the lower part, grades upward into sandstone. * * * The sandstone which overlies the shale has lenses of shale and limestone * * * A bed of clay 1 to 5 feet thick overlies this shale and sandstone, and underlies coal No. 5. Coal No. 5 and associated strata. — No. 5, or 1 [arrisburg coal, is found in Jackson Count}' east of its outcrop wherever the drill has penetrated to its horizon. It is found underlying only T. 7 S., R. 1 \Y., and adjacent parts of T. 7 S., R. 2 W., and T. 8 S., Rs. 1 and 2 W. The outcrop which is obscured by the drift lies about three-fourths of a mile west or south of the outcrop of coal No. 6, as shown on the map (PI. I ). The records of 21 drillings in this part of the county that have penetrated the full thickness of the coal show a variation in the thickness between 44 and 70 inches; 3 holes show less than SO inches, 12 a thickness between 50 and 60 inches, and 6 a thickness greater than 60 inches. Hie average of 21 measurements is 55 inches. The following description is given by Shaw and Savage: 3 The sequence of strata associated with the Harrisburg coal is well exposed in the south bank of a creek in the E. % sec. 1, T. 9 S., I\. 1 E., where the following section was made : Section near I he middle of I lie E. ;/> see. I , T. V .V., A'. / /:'. Thickness /•'/. in. 5. Shale, gray, yellowish where weathered 4 4. Shale, soft, gray, calcareous; many fossils 1 1 3. Limestone, single layer, hard, bluish gray, argillaceous 1 2. Shale, black, fissile, finely laminated; contains numer- ous more or less round "niggerheads" or iron-stone concretions 8 to 30 inches in diameter 6 9 1. Harrisburg coal ( No. 5) 4 24 COAL RESOURCES OF DISTRICT II The black shale overlying the Harrisburg coal is locally as much as 15 feet thick, but generally its thickness is between 6 and 9 feet. * * *. A peculiar black laminated shale, such as that above the Springfield coal (No. 5), farther north, generally overlies the Harrisburg coal in this region. In the vicinity of Springfield and in other portions of the State there is, imme- diately above the ■ Springfield coal seam and at the base of the black shale, a local pyritiferous band a few inches thick, with many fossils, in most places marine, showing the shales to be true marine deposits. The limestone overlying the roof shale of the Harrisburg coal is 12 to 36 or more inches thick. The limestone is comparatively resistant, and if it were thicker no doubt it would form hills. It outcrops more extensively than any other layer above the Pottsville, the principal exposures being along Beaucoup Creek 2 to 3 miles southeast of Finney and 1 to 2 miles southeast of Den- mark. Above the limestone is a thin bed of rather soft gray calcareous shale * * * succeeded by a bed of gray shale, 10 to 14 feet thick, which is generally overlain by a limestone bed 4 to 10 feet thick. Coal A?o. 6 and under clay. — Above the limestone last mentioned is the clay underlying coal No. 6. This clay varies in thickness from 1 to 3 feet in this area and generally contains impressions of the roots of a plant, Stigmaria. The overlying coal is 7 feet 3 inches to 12 feet 5 inches thick, though the seam where much broken by shale reaches a thickness of 16 feet 9 inches. The average thickness of the bed including the "blue band" in 22 records is 9 feet 6 inches. The coal is characterized by a layer of dirt or bone or shaly coal, known as the "blue band," which lies 18 to 30 inches above the base of the coal. Near the east boundary of the district this shale in places meas- ures 6 to 11 inches, but in most places 4 the "blue band" is much thinner, being rarely over 3 inches in thickness. The approximate out- crop of this coal is shown on Plate I by a broken line. The portion of the cotmty lying south and west of this line represents the area in which the Carbondale formation below coal No. 6 immediately underlies the surficial deposits. MCLEANSBORO FORMATION General character. — The McLeansboro formation in southern Illi- nois is barren of workable coal beds except possibly in small areas, and consists very largely of shale and sandstone. As it is much better developed in adjacent districts than in Jackson County the reader is referred to bulletins describing Districts VI and VII where the forma- tion is discussed in detail. Only in the northeast part of Jackson County is there more than 200 feet of the formation present, and only 5 drill holes out of a possible 27 in T. 7 S., R. 1 W., show so much. Shale and limestone immediately overlying coal No. 6. — Coal No. 6, or Herrin coal, is overlain by a bed of shale of somewhat variable 4 See Bulletins 11 and 15, Illinois Coal Mining Investigations. GENERAL GEOLOGY 25 character 5 to 78 feet in thickness. The shale is described in the drill- ing records as "clay shale," "sandy shale," and "black slate." One log records 46 feet 8 inches of sandstone above the coal. The black "slate" is commonly found at the top of the shaly strata and in places lies immediately upon the coal. There may be great variation in the succession reported in the same square mile. For instance out of 12 records of drilling in sec. 29, T. 7 S., R. 1 W., one shows "slate" lying above the coal, another records 43 feet of strata between the coal and the black shale, and others show various intervals between these two extremes. The black "slate" is not everywhere present in the section. Commonly a bed of limestone overlies the strata described in the preceding paragraph. This limestone where it is found within 25 feet of the coal forms the cap rock in the various mines and is com- monly encountered in drilling. It has a widespread distribution in Illinois and can be identified by the aid of a small fossil (Girtyina) which it contains. In thickness the stratum varies from 1 to 7 feet, the average thickness being 3 or 4 feet. Where an interval greater than 25 or 30 feet separates the coal from the nearest limestone above, there is some hesitancy in making correlations with the limestone carrying Girtyina without additional evidence. The writers of the Murphysboro-Herrin folio believe that where a thick bed of shale overlies the coal the limestone lias been removed by erosion. In Bulletin 15 of this scries is expressed the belief that the limestone is more or less widespread over southern Illinois and that the underlying shale is of unusual thickness in cer- tain areas. The variation in the thickness of the shale is thought to be due to the difference in the amount of shrinkage of the underlying coal in its consolidation from peat, thicker coal shrinking more than thin coal. Certainly no evidence is at hand to show that the erosion which is conjectured to have removed the black shale and limestone at any place removed any part of the closely subjacent coal. Strata above the limestone cap rock of coal No. 6. — Overlying the limestone which forms the cap rock of coal No. 6, shale described in the records as "clay shale", "sandy shale", "blue slate", and "fire clay" is recorded commonly about 20 feet thick, but possibly in places not over 10 feet, and elsewhere possibly as much as 45 feet. Above this is a limestone which has an average thickness from 12 to 14 feet but is thinner in some places. It is not recorded in all the logs. A thin coal 12 to 14 inches in thickness is reported in a number of the drill holes at an interval of 50 to 60 feet above coal No. 6 with another and thinner seam about 10 feet higher. Their distribution. 26 COAL RESOURCES OF DISTRICT II however, seems to be restricted to a small area. It is thought not im- probable that one of these thin coal beds may be the same as the thin seam found 25 to 50 feet above coal No. 6 in District VII and described by Mr. Kay in Bulletin 11 as coal No. 7. Concerning the rest of the McLeansboro section the data at hand do not warrant generalizations. QUATERNARY SYSTEM PLEISTOCENE SERIES Glacial till. — Glacial till mantles almost the entire district except the comparatively small area of the stream valleys from which it has been removed by erosion. It consists of a mixture of clay and more or less decayed pebbles and bowlders of many kinds of rock. The till has a rather uniform thickness of about 15 feet. In general those parts of the county above an elevation of 400 feet are underlain by a greater or less thickness of till covered by fine yellow clay, or loess, which is reported to average about 10 feet thick, so that the surface covering is not uncommonly 25 to 35 feet thick. This thickness of glacial till is of no special moment in the exploitation of the coal beds. Valley fill. — Those parts of the county lying below an elevation of 410 feet above sea level along the principal valleys are very likely to be underlain by a varying amount of silt and sand, not improbably water soaked. This alluvial material is in places as much as 120 feet thick. In places near the outcrop of coal No. 2 near Murphysboro the irregularities of the rock floor below the valley fill affect the thick- ness of the roof above the coal to an important extent. The mines of Big Muddy Coal and Iron Company near Big Muddy River have found that considerable care must be exercised in opening up new work to avoid weak or thin roof. For a discussion of the origin of the allu- vium which has no special bearing upon the coal resources of the region, the reader is referred to the text of the Murphysboro-Herrin folio, where the subject is discussed in detail. The following sections show the character of the surficial material near Murphysboro : Section of surficial material in the SW. cor. SE. y A NE. y A sec. 4. T. 9 S.. R. 2 li Description of strata Thickness Depth Clay, yellow, sandy Clay, gray Clay, gray, sandy , Sand, yellow Clay, blue, sandy . Ft. 18 10 1 6 15 Ft. 18 28 29 35 50 GENERAL GEOLOGY 27 Section of surftcial material in the SW. cor SE. y A NE. V A sec. 4, T. 9 S., R. 2 W . Concluded Description of strata Thickness Ft. in. 16 1 2 15 4 4 5 6 6 Depth Clay, red Clay, gray, sandy Clay, red Clay, gray, sandy Clay, brown, sandy Clay, green, sandy Sand, yellow, and gravel, mixed.... Shale, yellow, sandy Shale, gray Section of surficial material 500 feet southeast of center of the SW. % sec. 3, T. 9 S\, R. 2 W. Description of strata Thickness Depth Clay, gray Clay, yellow, sandy Clay, blue, sandy Sand and clay mixed Quicksand Clay, blue, sandy Quicksand and gravel mixed Clay, red Quicksand Clay, red, and sand mixed Shale, blue, sandy Sand, clay, and coal mixed Shale, blue, sandy, with concretions. The thickness of the alluvium in various parts of the district along the principal valleys is shown in the following table: Table 1 — Recorded thicknesses of the drift in various (/roups of drill holes along the principal valleys in Jaclcsou County Township and sections Thickness Feet T. 7 S., R. 1 E. T. 8 S., R. 2 E. f 3, 4, and 9 29 — 56 IS and 20 28 — 55 24, 27. and 28 31—64 29, 30, and 32 15 — 46 2 99 7 4—16 11 and 14 85 —121 16, 21 and 22 79 —1 10 26 and 27 43 — 68 28, 29, 30, 2>2, and 33 10 — 95 34 and 35 49 —114 28 COAL RESOURCES OF DISTRICT II T. 9 S., R. 2 E. <" 1, 2, and 3 21—90 4, 5, 8, and 9 — 97 10, 11, and 12 13 — 80 ?100 Structure method of showing structure The term structure as used in geology commonly refers to the atti- tude or "lay" of the rock layers; that is, whether they are flat lying, inclined, folded, or broken by faults. Structure of this kind can be represented by photographs and sketches, by diagrammatic cross-sec- tions and block drawings, but most accurately by means of structure contours. The use of structure contours to show differences in eleva- tion or relief has been explained with considerable detail in preceding bulletins 5 of the series so that an explanation will not be necessary at this place. The reference stratum used in delineating the structure shown on Plate I is the bottom of No. 2 or Murphysboro coal. In preceding bulletins the reference stratum has commonly been the surface of the coal bed used. The bottom rather than the top of the bed is used, since the seam is divided into two benches by a considerable thickness of intervening strata, and the lower bench rather than the upper is mined ; it is believed, therefore, that a structure map based upon the lower bench will be more useful and more accurate than one based upon the upper bench. The structure contours are represented on the map by the prom- inent irregularly curved red lines which cross the map in a general north-south direction. These lines show the position of coal No. 2 above sea level. Since in this area as in general throughout the Illinois coal basin the beds of the Pennsylvanian series are essentially parallel, the general geologic structure is indicated by the lines representing the elevation of the base of this bed. RELIABILITY OF STRUCTURE CONTOURS The reliability of the structure contours is affected: (1) by the accuracy of the surface elevations; (2) by the variability of the calcu- lated intervals between coal No. 6 and the base of coal No. 2; and (3) by the number and distribution of the points whose altitudes are known. That part of the district lying within the Murphysboro and Herrin quadrangles contains accurately determined surface elevations. The reference strata are coal beds that have been extensively worked and whose depths below the surface have been noted in numerous shafts, 'Bulletins 10 and 11, Illinois Mining Investigations. GENERAL GEOLOGY 29 wells, and drill holes. At most such points the altitude of the surface was obtained by hand level or barometer from some of the numerous bench marks, and the determinations have involved short horizontal distances and small possibilities of error. The variation of the interval between the two coal beds is more likely to lead to a mistake in determining the altitude of coal No. 2. In T. 7 S., R. 1 W., very few of the drill holes reached the lower coal, and at a few places in the township the contours are based upon the altitude of coal No. 6 by assuming the interval between the coals to be about 250 feet. In the northeast corner of the map of Jackson County, north and east of the outcrop of coal No. 6, are shown the contours based upon the surface of coal No. 6 for this same area. These connect with the contours shown on the maps of District AT and District VII. 6 On account of the scarcity of outcrops drill holes and mines are the principal sources of information. These are fairly evenly dis- tributed so that error arising from the scarcity of determined altitudes of recognizable strata is probably not great. The dip of the coal in the mines also affords some information for working out the structure, though the assumption of a uniform dip between determined points may be a source of slight error. A few faults having a throw of 8 to 22 feet, local irregularities in dip, and low folds were found in some of the coal mines and in a tew surface exposures. Local irregularities such as these do not appear in the structure contours on the geologic map. Inasmuch as nearly all the drill holes and mines are located within the boundary of the Murphysboro and Herrin quadrangles, and as accurate elevations are lacking for the few localities outside the quad- rangles, the structure is not shown beyond the limits of these areas. USES OF THE STRUCTURE MAI" The primary purpose of the structure map ( Plate I ) is to show the structural features. The coal stratum slopes away or dips as shown by arrows from contour lines of higher elevation to those of lower. In addition to the usefulness of the structure contour map in showing the lay of the coal, it can be used to determine the approxi- mate depth of the coal bed. In case the depth of the coal is desired at some point crossed by a structure contour line, it can be readily calculated by subtracting the elevation shown on the contour line from the surface altitude. If the point lies between two contour lines, its relative distance from them is observed, and the elevation of the coal e Bulletins 11 and 15, Illinois Coal Mining Investigations. 30 COAL RESOURCES OF DISTRICT II approximated accordingly, after which process the regular calculation can be made. One of the special services of the coal structure map in Illinois has been to determine the possible areas of oil and gas accumulation. It has been found as a rule that structural features affecting the "Coal Measures" affect also the underlying rock to a considerable depth in the same way, though possibly to a greater or less degree. A relation- ship of areas of accumulation to anticlinal folds and domes is known to exist, and the fact that, at least in some places, domes in the coal strata indicate conditions favorable for oil and gas has given added value to structure contours on the coal beds. STRUCTURE OF DISTRICT II GENERAL FEATURES The structure of District II is dominated by an uplift in the south- western part which results in a general northeastern dip. The top of the Potts ville sandstone, for instance, which is 850 feet above sea level near Sand Ridge, drops to about 300 feet below in the northeastern corner of Jackson County. The average slope of the strata is 50 to 75 feet per mile, but in the hilly country the Pottsville sediments slope in places as much as 10 degrees, or 1 foot in 6. The area of greatest uplift is flanked on the east by steeply dipping strata and is terminated on the north by a fault of 100 to 200 feet throw. Coal No. 2 outcrops along the flanks of the anticline but does not rise over the crest, which is underlain by Pottsville sandstone. The coal continues for some distance farther west on the north side of the fault than on the south side. DETAILS OF STRUCTURE The general northeast dip of the coal is modified by more or less pronounced irregularities. The most important of these are: (1) a sharp anticline in the southeast quarter of T. 7 S., R. 1 W. ; (2) an unsymmetrical broad anticline in the west side of townships lying in R. 3 W., extending south from near Ava to T. 9 S., R. 3 W. ; (3) an east-west syncline at Sato; (4) an anticline lying just north of the syncline last mentioned and extending east, curving somewhat north- ward to the county line; (5) a broad, somewhat irregular syncline plunging northeastward and extending from the southwest corner of the district in T. 9 S., R. 3 W., to the syncline in T. 7 S., R. 1 W. ; (6) the fault near the Perry County line. Of these irregularities only the first lies entirely within the area underlain by coal No. 2. The coal is more or less involved in the others. The various structural features are described in greater detail in the following paragraphs. GENERAL GEOLOGY 31 1. The anticline in T. 7 S,, R. 1 W., is determined from elevations of the coal in three drill holes located in sections 26 and 27. A differ- ence in elevation of coal No. 6 amounting- to 150 feet is indicated by these three holes arranged in a linear manner in the north half of the two sections. It is not known whether this difference in elevation is due to faulting or to folding, and the projection of the crest of the anticline northward as a narrow structural ridge is conjectural. The more satisfactory delineation of this structure will have to wait for additional drilling along the supposed crest of the fold. 2. The broad anticline south of Ava for the most part lies west of the outcrop of coal Xo. 2 and therefore without the district, except that the coal in places rests well up on the flank of the anticline in uneroded outliers of little importance. Only that part of the anticline in which the coal is involved is shown on the structure map (PI. I). The full details of the structure to the west appear in the Murphysboro- Herrin folio, to which the reader is referred. 3. The syncline extending east from near Sato is little else than a low place in the crest of the general anticline described under ( 1 ). At the position of this syncline the coal extends more nearly across the anticline than elsewhere, a small area of coal existing on the west (lank of the anticline near Ava. As the bed outcrops rather extensively, it is exploited by numerous drift mines. 4. The anticline north of Sato extends eastward into the coal field to the Illinois Central Railroad, and possibly as far as Klkville. where drilling indicates the presence of a slight terrace interrupting the general eastward dip of the strata. As drilling north of Vergcnnes is very meager, the delineation of this structural feature is left indefi- nite, being indicated by broken lines. An oil prospect sunk on what is thought to be the crest of the fold was unsuccessful. 5. The syncline plunging northeast from the southwest corner of the district is part of the general northeastward dip of the coal basin along its southwestern margin and culminates in the trough which lies between Elkville and the anticline in the southeast quarter of T. 7 S., K. 1 VV. This trough is the southern continuation of a wider basin lying east of the Duquoin anticline in Franklin, Perry, and Jefferson counties. 6. The most conspicuous structural feature of the district, as presented in the map, is the fault extending in an east-west direction near the Perry County line. This displacement, amounting to 100 to 200 feet, has been traced for a distance of at least 4 miles west from the outcrop of coal Xo. 2 south of the fault. North of the fault line 32 COAL RESOURCES OF DISTRICT II the coal is believed to be present in a narrow strip in Jackson County extending northward into Perry County, although there has been no drilling in that strip and the westward extension of the coal has not been determined. The extension of the fault line eastward from the outcrop is obscured by valley fill and glacial till. It is possible that it may be a continuation of the faulted area which traverses Williamson and Franklin counties in a direction running slightly north of west, possibly entering Jackson County due west of Hallidayboro. If this faulted zone persists through Jackson County, it will account for the considerable differences in elevation of the coal noted in the southeast quarter of T. 7 S., R. 1 W., and interpreted above for want of better evidence as being due to folding. So far as known, the mine at Halli- dayboro has not encountered faulting. Figures 3 and 4 show the structure and position of the coal along east-west and north-south lines in Jackson County. Feet W 600 400 200 Sea -^ Sv "--^ Coal E level *o. 6 ^__Coa/ Ho.2 _ 200 400 Fig. 3. — East-west section across the part of the Murphysboro and Herrin quadrangles in Jackson County. Feet 600 -j 400 200 H Sea level Fig. 4. — North-south section across the fault in Jackson County. CHAPTER IV— ECONOMIC GEOLOGY OF THE COALS Pottsville Coals The following is the description given by Shaw and Savage : x The coals of the Pottsville formation are relatively unimportant. A short distance above the middle of the formation is a lenticular bed of coal, which locally attains a thickness of 2 feet, but which is absent from a considerable part of the area. One of the best exposures of this bed is in the bank of a small stream in the SE. % sec. 8, T. 8 S., R. 3 W., where 20 inches of good short-grained coal may be seen. The next coal is about 75 feet higher and is nowhere more than 1 foot thick. The only Pottsville coal so far worked, locally known as the Pocket coal, lies 50 to 70 feet below the top of the formation. It is of Mercer age and is probably contemporaneous with the variable and lenticular beds that in other portions of the State have been called coal No. 1. This bed has been opened near the middle of the SW. % sec. 7, T. 9 S., R. 2 W., where it is of excellent quality and about 3 feet thick. The bed is also found in the NW. % sec. 18, T. 8 S., R. 3 W., but is there pockety and scarcely workable at present. ( ARBONDALE COALS COAL NO. 2 DISTRIBUTION AND THICKNESS The lowest coal bed of the Carbondale formation is No. 2 (Mur- physboro) coal. The Murphysboro coal is probably identical with the bed mined at La Salic known as the "Third Vein", and with the coal mined at Colchester. The coal is thought to be absent or at least not of workable thickness in the eastern part of the district, but is almost continuously workable along the foot of the hilly country near and north of Murphysboro. In the vicinity of Murphysboro it is divided into two beds, each of which has been mined extensively. It has also been mined one and a half miles northwest of ( >rayille, at Bryden, at Sato, and at points one and a half miles south of Ava, and two miles northeast of Sato. The thickness of coal No. 2 is exceedingly variable, largely because the vein is commonly split, but also because of a gradual thinning toward the east. Numerous observations of the thickness of the bed have been entered in Table 2. Drillings are more numerous in T. 8 S., R. 1 W. than in other townships. Where the bed is split the upper seam commonly varies from 24 to 45 inches in thickness, and the lower bed from 30 to 48 inches, being slightly thicker than the upper bench. Where only one bench is recorded in the drill record it commonly ranges, in the district as a whole, from 47 to 88 inches in thickness. 'Shaw, E. W., and Savage, T. I-'.., (J. S. Geol. Survey Geol, Alius, Murphysboro-Herri folio (No. 185), p. 13, 1912. (33) 34 COAL RESOURCES OF DISTRICT II rf CM ^t r-H ^ On CO 00 co CO vO CO CO CO (M CO CO O CO i-H 1 — 1 : CM ^ • CM CM '-' '-' Tj- — 1 CO to ~ : ^H ^ r— 1 5 cm ; -re N — ' co CM CM - ON cm GO CM 1^ CM VO CM LO CM CM CM 0\ oo r^ C\J lO 1-1 ^ CM *-« ^ _Vj ^ CM 5 ^ ^ C\J - CM i-i CM o ~ - ^ ^ * s — ^ £ ~ ~ 1 cm 1 : « - w < C/3 .S _C en C M u IS H S" C £ C c ^ J ^ in c i^ * 8 . oc p4 a CM ECONOMIC GEOLOGY OF THE COALS 35 00 oo 00 00 00 o 00 On t^ LO ro CM 1^ CM - CO - i— 1 - i—i CM ~ CM - - LO CM ^ o ON NO LO VO ro NO t^ LO lO Tt LO ro LO CM LO $ -1- NO -1- ^h CM - : ^ »— i CM ^h CM CM -* - 1 : ~ - fH ^ ^ CM ^ nN CO 30 H co oc CM 36 COAL RESOURCES OF DISTRICT II Attention has already been directed to the restricted distribution of the thick, undivided Murphysboro coal. Although without much question one or more coal beds continuous with part or parts of the Murphysboro coal underlie all of District II and are correlated from drill hole to drill hole as coal No. 2, the area of coal workable at present, at least, is small. There is an already nearly exhausted area of thick coal near Murphysboro and a less fully known area along the outcrop northeast of Sato where it is being mined at a country bank. The location of the commercial mines at Murphysboro (see Plate I) is determined by the area of thick coal and fairly well indicates its outline. Mine workings extend as far east and north as conditions will allow ; shale partings finally become too numerous or too thick to handle. To the west and south the minable area extends to the outcrop, or until the roof becomes unsatisfactory. There is some tendency also for the bed to split up along the southwest margin of the district. It is prob- able that the original area of thick coal near Murphysboro did not exceed 15 square miles and that two-thirds or more of that coal has been mined or rendered unminable. 1400 Feet Fig. 5. — Diagrammatic illustration showing the thickening of the parting in the Harrison mine, Big Muddy Coal and Iron Co., west rib of 9th north, west. Bearing of entry, N. 41° E. PHYSICAL CHARACTERISTICS The coal has a bright luster, contains bands of dull and glance coal and mother coal, breaks with a hackly fracture into blocks, is some- what harder than the upper coals, contains little hygroscopic water, and withstands considerable exposure without slacking. The bed commonly contains a few sulphur balls and bands which are discarded by the miner. The clay which commonly separates coal No. 2 into two benches is of variable thickness. In one mine the parting varies from 18 inches to 35 feet and in other mines may be entirely absent in some places or as much i as 3 or 4 feet thick in others. The greatest interval between the two ibenches as recorded in the drill records is 43 feet 6 inches. ECONOMIC GEOLOGY OF THE COALS 37 The accompanying drawing (fig. 5) sketched in the Harrison shaft, Big Muddy Coal and Iron Company, illustrates the variations in thick- ness of the parting within a distance of about a quarter of a mile. The parting is commonly gray shale, thin bedded, and filled with plant impressions and may appear at various positions in the seam. In places it becomes very carbonaceous and is likely to become more car- bonaceous near the base than at the top. Bone coal serves as the parting locally. The sections of the coal given in the following pages include comments on the parting, as observed in the mines. DETAILED OBSERVATIONS Following are a number of detailed observations of the coal made in several of the mines of the district by members of the Investiga- tions or of the State or Federal Surveys. GUS BLAIR BIG MUDDY COAL CO., MINE NO. 2 General description. — Maximum thickness of the upper bed, 36 inches; mini- mum, 24 inches; average, 30 inches. Maximum thickness of lower hed, 48 inches; minimum, 32 inches; average, 42 inches. The shale parting varies from 18 inches to 25 feet in thickness and is present throughout the mine. The hed contains a little bone coal at the bottom. Over part of the mine both benches are worked, elsewhere only the lower bench. Where only the lower bench is worked the parting serves as roof where it is thick enough, but where it is too thin the upper coal forms the roof. Xo attention is paid to the cleat, though it is recognized that the coal works easier if worked on the face. Section, face of room on third northeast entry. — Thickness of upper bench 2+ feet. Coal harder, more porous than the lower coal; contains numerous lenses of mother coal. The parting has a thickness of 2 feet. The upper \ x /> feet is gray shale, thin bedded and filled with plant impressions. The lower inches is shale with coal in thin hands. The lower bench of coal is 3 l /j feet thick. The upper inches is laminated, dull, and glance coal. The mid- dle two feet of coal is very uniform in character. There- are few or no hands of glance coal; in the lower foot of the hed the coal is soft, bright, with hands of coal separated by layers of mother coal, giving a laminated appearance. There is a little hone coal at the bottom of the hed. The cleat is strongly devel- oped — face N. 35° \Y.. butt X. 38° E. Some calcite occurs along the cleavage faces. This section is reproduced graphically in figure o, Xo. 1. BIG MUDDY COAL AM) IKON CO., MINK NO. Section I. — Top coal has a thickness of 24 inches; harder than the bottom coal; cleat planes cut the coal into small blocks making much line coal. Calcite occurs along the cleavage planes. Coal much laminated and has partings of mother coal. The parting or the shale between the two benches is only a knife-edge in thickness. The lower coal is 44 inches thick. For a graphic reproduction of this section sec figure (>, Xo. 2. Section 2. — Top coal has a thickness of 22 inches and contains layers of glance coal separated by hands of mother coal. The parting is of knife-edge 38 COAL RESOURCES OF DISTRICT II hi ii i! m 2 i co .2 COS CO Sulphu B Bone CO •* d to CM ,- o m ftltlrfiiltii «- oo , -, 3 Cfl K^ r\l W A o Ti £ t*5 o rt O PS !i H 6 ^ O 55.3 y y u CCrt WiWiriWiWiWi'ii lll ml i l l M 'lliill n iililil l !' 1 ' o 6, uu 1 o o o o o be CJvJ^ J3 3 3 3 pq ^SS!^ ^ t> bo be be £ bc^ S3ljOU| ECONOMIC GEOLOGY OF THE COALS 39 thickness. The lower coal has a thickness of 48 inches and is more blocky than top coal. The bottom of the lower bed commonly contains bone coal; near the outcrop this becomes 8 inches thick. For a graphic reproduction of this section see figure 6, No. 3. Cleat. — Several measurements of the cleavages have been made in this mine as follows; the first column gives directions of the better cleavage. Main haulage road 1,000 feet from shaft N. 35° W. N. 32° E. Room 5, 3d south. 8th east N. 32° W. N. 30° E. Room 4, 6th north, 5th east N. 28° W. N. 20° E. On the main south entry two partings of gray shale are found in the coal — one a 3-inch parting 6 inches from the bottom, and the other a 4-inch part- ing 18 inches from the bottom. BIG MUDDY COAL AND IRON CO., HARRISON MINE Section 1, face, 14th northwest entry. — The upper bench has a thickness of 20 l / 2 inches; coal is fairly bright, has considerable mother coal scattered through it in lenses and partings; the cleat cuts the coal into small blocks. The parting is very carbonaceous shale with coal streaks scattered through it, having a thick- ness of 3 to 4 inches. The lower bench has a thickness of 38 inches; it is bright, hard, blocky; contains a few balls of sulphur; has partings of mother coal be- tween glance and dull coal; the lower 2 inches has partings of bone coal. This section is shown graphically as No. 4 in figure 6. Section 2, room 87 off the 4th northwest entry. — The top coal has a thick- ness of 28 inches; coal more blocky than in section above; somewhat laminated with mother coal in partings and lenses; glance coal is scattered through in bands. The parting is gray shale with only few plant impressions; thickness 11 inches. The bottom coal has a thickness of 42 inches; is harder than the top coal; more blocky; cleavage planes well developed; glance coal in bands is scattered through the lied. The coal contains a few sulphur balls. For a graphic reproduction of this section sec figure (>. No. 5. Section 3, room 7, off the 7th northeast entry. — Top coal has thickness of 24 inches; coal more blocky than usual in the mine; has bright, banded appear- ance; contains a small amount of calcite ; there are numerous lenses and bands of mother coal; a few streaks of bone coal occur in the upper 1 inches of the bed. The parting is bone coal 1 inch thick. The bottom coal has thickness of 43 inches; blocky bright and dull coal with bands of brighl coal scattered through it; a small amount of mother coal present; bottom 1 inches of the bed is bony and tilled with calcite plates along the cleavage planes, for a graphic reproduction of this section see figure 0. No. <>. Section 4. 1st northwest entry. — Top coal has thickness 22' _• inches; coal has a bright, banded appearance; contains lenses and layers of mother coal; 3 inches of bone coal occur in the lop of the bed; there i^- a little sulphur. The parting is 2Yi inches thick; soft claw bluish gray, with varying amounts of car- bonaceous matter. The bottom coal is 18 inches thick; bright coal, with a large amount of glance coal present in bands; very little mother coal and no sulphur; bottom coal hardest as elsewhere over the mine. This section is reproduced graphically as No. 7 figure 12. 40 COAL RESOURCES OF DISTRICT II Q ! •* 5^ a 2 "" -o ,n L) 3 +1 * £ o 1 s ames Ice & m. Ca rtside sbit & B. Sc o &*&&&£* ECONOMIC GEOLOGY OF THE COALS — u ■s. a — >> o *5 ~ 3 E g u 1", s « v, y. p p — c0 ■s "i 2 1 i - eg rt u C en bfo COAL RESOURCES OF DISTRICT II Table 4. — Analyses of mine saniples of coal from Distr (Not exactly indicative of commercial ict II (Jackson Comity) output) I -c County Proximate analysis of coa 1 1st: "As reed," with total moisture. 2d: "Dry" or moisture free 7-12 7-12 7-12 7-12 7-12 7-12 7-12 7-12 12 7-12 8-12 8-12 15 ! 8-12 55 4-12 55 4-12 Jackson--. Jackson.-. Jackson.-. Jackson.-. Jackson... Jackson--. Jackson.-. Jackson... Jackson--. Jackson--. Jackson__. Tackson... r,;-, -12 Jackson. Jackson. Jackson. Jackson- Jackson. Jackson. I 2 7.72 Dry 8.77 Dry 9.18 Dry Dry 10.91 Dry 9.76 Dry 9.51 Dry 9.37 Dry 9.99 Dry 9.25 Dry 9.56 Dry 9.20 Dry 8.32 Dry Dry 8.91 Dry 10.88 Dry 7.17 Dry Drv 35.03 ! 38.02 48.56 52.62 32.78 50.58 35.93 55.44 34.70 51.58 38.20 56.80 33.23 52.43 36.87 58.18 33.51 51.20 37.61 57.47 33.45 52.07 37.06 57.71 33.13 52.12 36.62 57.59 33.39 49.29 36.48 54.38 32.51 51.88 36.12 57.63 34.67 50.53 38.20 55.68 34.52 50.47 38.16 55.83 34.48 50.54 37.97 55.66 35.28 51.10 3S.49 55.74 35.00 49.74 38.40 54.57 34.03 53.17 37.36 58.37 31.71 48.90 35.57 54.88 36.36 45.25 39.18 48.74 35.30 44.96 38.72 49.30 8.63 9.36 7.87 8.63 4.54 5.00 4.46 4.95 4.38 4.92 4.72 5.23 5.24 5.79 7.95 8.78 5.62 6.25 5.55 6.12 5.45 6.01 5.78 6.37 5.30 5.77 6.40 7.03 3.89 4.27 3.51 3.55 11.22 12.08 10.92 11.98 2.01 2.18 2.00 2.19 .70 1.14 1.23 1.0S 1.20 2.11 2.32 .62 1.41 1.56 1.32 1.46 1.44 1.59 1.39 1.53 1.69 1.85 1.15 1.26 3.92 4.22 3.46 3.79 .29 12248 .31 13272 14839 .02 12253 .03 13430 14885 .05 12752 .03 14010 14867 .33 12709 .36 14103 14926 .20 12503 .23 14034 14863 .51 12629 .56 13996 14S74 .94 12500 1.03 13814 14758 .94 11972 1.03 13208 14671 .20 12308 .22 13673 146S6 .13 12528 .14 13804 14834 .27 12483 .30 13781 14811 .19 12481 .21 13746 14814 .19 12671 .21 13822 14791 .07 12436 .08 13645 14830 .07 12844 ■ m 14101 14823 .30 11594 .34 13009 14531 .43 11678 .47 12581 14617 .50 11547 .54 12663 14676 ECONOMIC GEOLOGY OF THE COALS 43 m en * VO LO CM CM ,-H ' —l 1—1 CM u o s X> rt O o O O o o o O O £ £ Ih l_ s- Uc Ul u j- £ co u-j Tf Tf t^ 00 vO 00 X or; "~ ' ' ' LO CM LO r^ *~ ' 00 vo Tt VO lo w co co 00 00 CO f^ CM ^r rj- "fr H On Tj- o LO CM 00 00 O CM I— 1 o CM o i—i r— 1 pq Ih ~ On CJi On CM (N) CO r— | co CO A 00 CM LO to On LO O On On ■^ CM rH CO CO CM ^ rt CM CM 00 CM CO CO < *o E *c S *" — ' CO X on NO On On 1- X > en U . ~ ^ bo OJ p* i CJ u ^J rt • ss PJj (71 OS fe On CM On CM X X o 44 COAL RESOURCES OF DISTRICT II Cleat. — The following measurements of the direction of the cleavages have been made ; the first column gives the directions of the better cleavage : Room 10, 13th northwest entry N. 20° E. X. 43° W. Face, 14th northwest entry X. 43° W. 1st northwest entry X. 32° E. X. 35° W. Room 7, 7th northeast entry X. 20° E. These measurements and others made during the last few years by various members of the Survey are shown in tabular form in Table 3. Several additional graphic sections based upon these measure- ments and upon drill records are also shown in figure 6. QUALITY OF COAL NO. 2 Three samples from different parts of each of 5 mines have been collected by members of the Investigations, and analyses made under the direction of Prof. S. W. Parr. These analyses have recently been published in Bulletin 29 of the State Geological Survey and are repro- duced below in Table 4. The comparative quality of the coal is illustrated by the analyses presented in Table 5 and the graphic presentation of the analyses in Plate III. The analyses make apparent immediately the reason for superi- ority of the No. 2 (Murphysboro) coal. The percentage of fixed car- bon is higher than in the other coals of the State, and the percentages of ash, moisture, and volatile matter are correspondingly lower. ROOF OF COAL NO. 2 The roof of coal No. 2 in some places is the gray shale above the undivided bed ; in some places the upper bench of the divided bed ; and in still other places, the parting between the two parts of the di- vided bed. The gray shale above the bed is a slabby thin-bedded shale of varying shades of gray depending upon the amount of carbonaceous material present. It generally falls in thin sheets. The character of the roof of coal No. 2 in the various mines of the districts is shown in Table 3. Not uncommonly between the coal and the gray shale is a few inches of draw slate which may be 4 feet thick in some places. Usually it is less than a foot thick, and in one mine 2 to 6 inches. The draw slate differs from the gray shale above in being more laminated and carbonaceous. Between the dark slate and the gray shale is commonly a thin layer of soft structureless clay resembling floor clay and known locally as "sheepskin". In No. 9 mine this clay seems to mark the top of the coal and black slate section, the slate appearing in more or less lenticular masses below, and in places it truncates the bedding of the slate. ILLINOIS STA1 COOPEI District 1 BULLETIN 16, PLATE ECONOMIC GEOLOGY OF THE COALS 45 The roof shale of coal No. 2 is the most valuable and accessible shale in the district. Near Murphysboro the shale forms an almost unbroken mass nearly 100 feet thick with a thin coal near the top, over- lain farther north by a heavy sandstone. That part of the shale that overlies a thin coal about 100 feet above No. 2 coal is being extensively mined by the Murphysboro Paving Brick Company at Murphysboro (tig. 7). The same bed outcrops near De Soto and elsewhere in the southern part of Herrin quadrangle and might be successfully worked at a number of places. It outcrops in a strip varying in width from a few feet to 2 miles and extends east from Murphysboro toward Car- bondale, and north from Murphysboro to the northwest corner of Ver- gennes Township where it is faulted down to some distance below the surface. Most of the outcrop lies near a railroad. Fig. 7. — Shale in the pit of the Murphysboro Paying Brick Co. (Photo by F. H. KavO FLOOR OF COAL NO. 2 Underlying coal No. 2 is commonly a bluish-gray sandstone, the thickness of which usually exceeds 5 feet. In places there is a layer of clay, commonly called "fire clay", between the coal and the sandstone. This may reach 4 or 5 feet in thickness and may contain streaks of coal and carbonaceous material. In some of the mines where this underclay occurs it has not been penetrated, but as the clay under the coal in the drill holes rarely exceeds 10 feet, it probably is generally of no great thickness. So far as is known, the clay offers no difficulty in mining: the coal. 4 COAL RESOURCES OF DISTRICT II STRUCTURAL IRREGULARITIES At least three kinds of structural irregularities of some importance are found in coal No. 2. These are faults or "slips", "horsebacks", and "rolls". These phenomena are like similar irregularities found in other coal beds of the State in greater or less frequency. It is not uncommon to find all three irregularities associated (fig. 8), but the horseback is a very common accompaniment of the slip (fig. 9). Fig. 8. — Diagrammatic illustration of a fault, slip, and horseback in mine No. 2, Gus Blair Big Muddy Coal Co. Scale 12 3 4 Feet Fig. 9.— Diagrammatic illustration of a horseback in mine No. 9, Big Muddy Coal and Iron Co. The faults or slips are slight displacements of the coal bed, the coal being offset along a fault plane. The slip plane not uncommonly terminates or appears to terminate a short distance above the coal, the overlying shale not being affected by the movement for more than the lower few inches. It seems apparent that in many places the fault- ECONOMIC GEOLOGY OF THE COALS 47 ing is' confined to, and due to, adjustments within the coal bed itself and not to major movements involving the entire held. The miners' horse is commonly a clay or sandstone filling along a slip or fracture across the coal bed. These fractures may be accom- panied by displacement and thereby become faults in the geological sense, or the bed may apparently have been pulled apart along the line of the slip without any displacement (figs. 9 and 10). 1003 ^^^^^fl 1 r . \L 1 >%^ Part _■ |:5HMiil ^L^^^H ■ 1 Bfiv M Fig. 10. — Diagrammatic illustration of a slip without displacement in mine No. 9, Big Muddy Coal and Iron Co. Any considerable body of shale embedded in the bed of coal is also spoken of by the miners as a "horse". The "horse" shown in figure 11 12 3 4 Feet Km;. 11. — Diagrammatic illustration of a horse in Harrison mine. I'.ig Mndd_\ < oal and Iron Co. has been traced for 1,000 feet in the Harrison mine of the Big Muddy Coal and Iron Company and still continues. The material forming the 48 COAL RESOURCES OF DISTRICT II "horse" is a hard, bluish-gray, micaceous sandstone, which fingers lat- erally into the coal and contains within it patches of coal or carbonace- ous material. It is not improbable that the sandstone was deposited contemporaneously with the coal, or at least before the entire bed was deposited, since the upper part of the bed continues across the sand- stone filling. Rolls are interruptions in the continuity of the bed whereby the roof shale extends appreciably below the top of the bed usually along a narrow area (fig. 12). Apparently they represent depressions in the Scale 12 3 4 Feet Fig. 12. — Diagrammatic illustration of a roll in mine No. 9, Big Muddy Coal and Iron Co. top of the coal at the time of deposition of the shale, or places along which the bed has suffered an unusual amount of shrinkage. The clay occupying the roll is commonly slickensided and filled with minute cracks indicating that movement has taken place. The not uncommon continuity of the upper bed of shale and coal across or nearly across the coal bed, as shown in figure 12, seems to indicate that originally the surface of the coal extended about level across the position of the roll, and that the difference in the thickness of the bed has resulted, subsequently, possibly from unequal shrinkage. The width of these rolls is commonly not great ; a width less than 10 feet is probably more common than greater widths. The extension of the rolls is known to be much greater than the width, but no data are available as to the actual length of any of them. The irregularities in the bed described in the preceding paragraph are not sufficiently frequent to be a considerable hindrance in mining. Where they occur there is commonly difficulty in holding the roof, and horses frequently need to be blasted out where the punching machines are unable to cut through them. Mining is somewhat hampered in certain districts by insecure roof condition, especially where the mine ECONOMIC GEOLOGY OF THE COALS 49 lies below a considerable thickness of valley fill previously described, and the thickness of shale above the coal is not great. These conditions are encountered especially where the mines are located on the terraces or river flats below elevations of 400 feet above sea level, and in those mines near the outcrop. In mine No. 2, Gus Blair Big Muddy Coal Co., the valley fill extends through the coal on the east side of the mine, so that bed evidently outcropped on the sides of the pre-glacial valley. As the material filling the pre-glacial valleys is in many places fine sand saturated with water, the roof becomes very insecure where the shale separating the coal from the sand is thin. Surface subsidence, moreover, is relatively rapid above areas of quicksand that have been undermined. In general, because of the nearness of large bodies of underground water to the coal bed, especially in the vicinity of Mur- physboro, the mines in this field have greater difficulty with water than most of those in other districts of the State. COKING OF COAL NO. 2 A coke of fair grade has been made from the Murphysboro coal across the river south of Murphysboro. A few years ago several dozen ovens were in operation, but at present no coke is being produced in the district. COALS BETWEEN COAL NO. 2 AND COAL NO. 6 COAL NO. 5 Of the coal beds between coal No. 2 and coal No. 6, none lias been exploited in District II. Of these coals the thickest is No. 5 (Harrisburg coal), which lies between 20 and 50 feet below No. 6 (Herrin coal). The area underlain by this bed is slightly greater than that underlain by the upper coal, since it outcrops about three- fourths of a mile south of the outcrop of coal No. 6. The thickness of the coal is very uniform over large areas, averaging 4 feet 7 inches for 20 drill holes. The available data in regard to the thickness of the seam have already been summarized in Chapter III. This coal has been extensively exploited in District V in Saline and Gallatin counties, and is known to be of excellent quality. The conditions for mining are favorable. The underclav is hard and does not creep readily. Above the coal is a bed of black shale which stands well as roof with little or no timbering. In many places in the lower part of the roof shale pyritic concretions or niggerheads are abundant. For further description of this coal in southern Illinois the reader may wish to refer to the forthcoming bulletin on District V. In Jackson County coal No. 5 is known only from drilling. Although 50 COAL RESOURCES OF DISTRICT II 3 m W t^ H ^ eo u w x >> oT CM* c c c c £ X rt 1— > ro" tT •»-i c G4I ^ c/i Limestone *c5 GC M u > *-" Shale cr. ^ 00* c o m .2 rJ cu Fire Clay o c/i N* S Sulphur O X W •^ H £ B rt - Bone s- t< c C 1 u U [• t" Oh tt,N M CO N ca <" 3*S ttr o eg ** o cfl o si ■-- ^h i-i eg eg eg eg eg M eg eo x H 6 a; C/3 t- 00 00 00 00 00 GO 00 oo CO l— a oc i- f :r n n (M rH M w so so - - :: i- ei f, so eg £ w w w £ w £ £ x: V, X X X -y. r g £ £ ^ w W W ^ w x x. X /. W ^ W W /- x 55 S5 j. '■£. .<-. -^ T3 — 1/ cfl JC ° fa ec «o o e-i ci ri ci eg ci e*i e-i O 1 c O H H 81 M »1 H -r ^- - - if d d d : i d ^yyyyyy d d h | X. X. | | w m <; u z a u a C I 6 | i | 6 ! ! U j j J u i Is ^ 1 1 j : u " § i u i | 4) w u j > i ' « ,9 ! 2 J ! "§ ° * - 6 * u ^ | g § U S *g J^M! = c o 2 2 ^ " « 3 1 SP o ^ IS 3 •- in cfl r /-, f< ^ ~. 5 o ° •« .SP u u z - ■ y J .h f U •7 K ^ ^ CO P •— CO ■j 'j pa u cfl d H M CO t lO » t— M « O H CO T3 5 8 x o -^ •- c — CO ft ^2 1 < INDEX PAGE Analyses of Illinois coals 42,43 Ava, anticline south of 31 coal No. 2 near 20 Beaucoup Creek 15 Big Muddy River 15 roof of coal near 26, 49 terraces of 14 Bryden, coal Xo. 2 near 20 Carbondale 15 i Carbondale coals 33-49 Carbondale formation, geology of 19-21 Coal, analyses of 42, 43 production of 11 "Coal Measures", see Pennsylva- nia}! series Coal Xo. 2, analyses of 42 coking of 49 description of 20-21, 36-37 distribution of 33, 36 floor of 41,45 mine notes on 37-41, 44 roof of 40,44-45 structural irregularities of 46-49 thickness of 33.34-35,41 Coal Xo. 5. description of 49-50 section of 23-24 Coal Xo. 6, analyses of 42 description of 24. 50-52 Danville district coal analyses... 43 De Soto, shale near 45 Devonian formations in drill holes 17 Elkville, anticline near M Fault near Perry County line. .. .31-32 Franklin County coal analyses... 43 Glacial deposits 14, 26, 27-28 Grape Creek coal analyses 43 Herrin coal, see coal Xo. 6 Kay. 1". H.. work of 11,26 La Salle district coal analyses... 43 Little- Muddy Liver 15 Loess deposits 14 PAGE Matthews, coal near 20 McLeansboro formation 24-26 Mercer County coal analyses.... 43 Mines in District II 53 Mining Experiment Station, co- operation with 11 Murphysboro, location of 15 coal Xo. 2 near 20, 21 shale near 45 Murphysboro coal, see coal Xo. 2 Murphysboro district coal analy- ses 43 Oil and gas, occurrence 29-30 Oraville. coal Xo. 2 near 20 Ordovician formations in drill holes 17 Pennsylvanian series described. . 17-26 Pleistocene series 26-28 Pottsville coals described $3 Pottsville formation described. .. 17-19 Quaternary system described . . .26-28 Lock Island County coal analyses 43 Saline County coal analyses 43 Sato, coal Xo. 2 near 20. 21 structure near il Savage, T. K., work of 11 Shaw. E. \\.. work of 11 Silurian formations in drill holes 17 Springfield coal, see coal Xo. 5 Springfield- Peoria coal analyses.. 43 Structure of district 28-32 relation of to oil and gas 29-30 Terraces of Big Muddy River. . . .13-14 Topography 13-14 L. S. Bureau of Mines, coopera- tion with 11 University of Illinois, coopera- tion with 11 Valley till along Big Muddy Liver 26 Vergennes sandstone, description of 21,22 White, EC D., work of 11 Williamson County coal analyses 43 Bulletin 1. Bulletin 3. Bulletin 10. Bulletin 11. Bulletin 14. Bulletin 15. Bulletin 16. Bulletin 17. Bulletin 18. Bulletin 2. Bulletin 4. Bulletin 5. Bulletin 6. Bulletin 7. Bulletin 8. Bulletin 9. Bulletin 12. Bulletin 13. Bulletin 91. Bulletin 72. Bulletii 83. Bulletii 99. Bulletin 102. PUBLICATIONS OF ILLINOIS GOAL MINING INVESTIGATIONS ILLINOIS STATE GEOLOGICAL SURVEY URBANA, ILLINOIS Preliminary Report on Organization and Method of Investi- gations, 1913. Chemical Study of Illinois Coals, by S. W. Parr, 1916. Coal Resources of District I (Longwall), by G. H. Cady, 1915. Coal Resources of District VII, by Fred H. Kay, 1915. Coal Resources of District VIII (Danville), by Fred H. Kay and K. D. White, 1915. Coal Resources of District VI, by G. H. Cady, 1916. Coal Resources of District II (Jackson Co.), by G. H. Cady, 1917. Surface Subsidence in Illinois Resulting from Coal Mining, by Lewis E. Young, 1916. Tests on clay materials available in Illinois coal mines, by R. T. Stull and R. K. Hursh, 1917. ENGINEERING EXPERIMENT STATION URBANA, ILLINOIS Coal Mining Practice in District VIII (Danville), by S. O. Andros, 1913. Coal Mining Practice in District VII, by S. O. Andros, 1914. Coal Mining Practice in District I (Longwall), by S. O. An- dros, 1914. Coal Mining Practice in District V, by S. O. Andros, 1914. Coal Mining Practice in District II, by S. O. Andros, 1914. Coal Mining Practice in District VI, by S. O. Andros, 1914. Coal Mining Practice in District III, by S. O. Andros, 1915. Coal Mining Practice in District IV, by S. O. Andros, 1915. Coal Mining in Illinois, by S. O. Andros, 1915. (Complete resume of all the district reports.) Subsidence Resulting from Mining, by L. E. Young and H. H. Stoek, 1916. U. S. BUREAU OF MINES WASHINGTON, D. C. Occurrence of Explosive Gases in Coal Mines, by N. H. Darton, 1915. The Humidity of Mine Air, by R. Y. Williams, 1914. Mine Ventilation Stoppings, by R. Y. Williams, 1915. The Inflammability of Illinois Coal Dusts, by J. K. Clement and L. A. Scholl, Jr., 1916. [