* £* *:::\{ --> | -- c. # , º, …? H & 8 { \ - ******. - I. : "A 1--" ºf | C (Reprinted, with slight revision, from The Journal of Geology, Vol. XII, July-August and October-November, 1904 . ... GLACIAL AND POST.GLACIALHISTORY OF THE HUDSON AND CHAM PLAIN WALLEYS - BY CHARLEs EMERSON PEET CHICAGO I Q O4 Q E. º 44, Low Point and - *\rese?-sº GPSºKwº ~. Goº-c, sº ºr c. * Carthage Landing; ºr. Pisaurº - "ss 14o, Mallett's Bay; - • *-es-- 8o, Maltaville; 4o Marlboro; 77, Mechanicsville;"142 as ºr ROY Missisquoi River; 85, Moreau Pond; 127, Morrison- .*****, ville; 93, Moses Kill; IoS, Mount Defiance; 122, Mount * ...)--" g-ac-ºssuº" - . Etna; 5, Newark Bay; 61, New Baltimore; 46, New 6,5c+(ots Acerº, Hamburg and Wappinger Creek; 63, New Scotland; 65, SS Gi Newtonville; 37, New Windsor; 114 North Branch of § Go Bouquet River and Tower's Forge; 62, Oniskethau, SSA Spraytkill, and South Bethlehem; 20, Ossining (Sing ~~~º Sing); 6, Passaic River; 2, Perth Amboy and Arthur Kill; 121, Peru; 117, Port Douglas; 88, Queensbury, Round Pond, and Jenkins Mills; 1, Raritan River and Bay; II.5, Reber; 54, Rondout: 39, Roseton; 79, Round Lake; 88, Round Pond, Queensbury, and Jenkins Mills; ro4, Rutland-Addison County Line; 123, Salmon River and Schuyler's Falls; 81, Saratoga Lake; 68, Schoharie Creek; 123, Schuyler's Falls and Salmon River; 20, Sing Sing (Ossining); 132, Snake Mountain; Ior, South Bay; 62, South Bethlehem, Spraytkill and Oniskethau; 124, South Plattsburg; 14, Sparkill Valley; 62, Sprayt- kill, South Bethlehem, and Oniskethau; 28, State Camp; 71, St. Johnsville; 18, Stony Point; 75, Teller Hill; Ioé, Ticonderoga; II.4, Tower's Forge and North Branch of Bouquet River; 128, Treadwell Bay; 52, Ulster Park; 25, Verplanck's Point; 64, Voorheesville; III, Wadham's Mills and Bouquet River; 46, Wap- pinger Creek; 47, Wappinger Falls; 130, West Beek- mantown; 5o, West Park; 112, Whallonsburg; 116, Willsboro; 139, Winooski River; 3, Woodbridge Creek; 96, Wood Creek; I41, West Milton and La Moille River. PO/U GAHN EPSIE Æ. 1eº-cs rºº"); 2.5 º }{crº e-rer- ºr 2. o …” gº a.Stº / . . tº erº" lau-a” £ie N tº # a oo “” se” ^s. C.” ^*, ºe" 418 CHARLES EMERSON PEET | and for the report on the Glacial Geology of New Jersey," under Professor Salisbury's guidance, work bearing on the problems here involved was carried out in 1897 and 1901. The main results here presented were in hand before the latter date, and the advance since then has been mainly in determining the crustal movement and in the analysis of facts bearing on the origin of the Hudson water body. To Professor Salisbury the writer is under obligation for the opportunity of detailed study of the Pleistocene formations of New Jersey and adjacent portions of New York, for early training in methods of investigation and mapping of those formations, and for suggestions in the original plans for the work, the results of which are here pre- sented. To Professor Chamberlin the writer is under obligation for assistance with difficulties encountered in this investigation, and for continued inspiration to perseverance in Searching out the truth. Neither Professor Chamberlin nor Professor Salisbury is responsible for opinions here expressed or for any failure to arrive at the truth. GENERAL STATEMENT OF TOPOGRAPHY OF EASTERN NEW YORK AND SOUTHERN NEW ENGLAND. Southern New England has been described as an upland rising gradually inland from the Sea and reaching elevations of 1,500 to 2,000 feet in southern New Hamsphire and Vermont.” Above this upland there rise higher elevations such as Mt. Monadnock, and groups of elevations such as the Green Mountains and the White Mountains. Below the upland, valleys have been sunk, a small amount near the sea, but deeper farther inland. These valleys are broad on the soft rocks and narrow on the harder rocks. Without assuming an identical history, this picture may be trans- ferred to eastern New York, where, as a first approximation to the truth, the country may be pictured as a rolling surface rising inland from the narrows at Long Island and Staten Island. Above this sur- face there are elevations, such as the Adirondacks and the Green Mountains. Below it there are depressions, such as the Hudson and Champlain Valleys. I See Glacial Geology of New Jersey, by ROLLIN D. SALISBURY, assisted by HENRY B. KUMMEL, CHARLEs E. PEET, AND GEORGE N. KNAPP (Vol. V of the Final Report of the State Geologist, 1902). 2 DAVIs, Physical Geography of Southern New England. GLACIAL AND POST-GLACIAL HISTORY 4I9 The Hudson Valley has three natural divisions: (1) the part south of the Highlands from Peekskill to the narrows at Brooklyn; (2) the Highlands from Peekskill north to near Fishkill; and (3) the broader Hudson Valley from near Fishkill to north of Glens Falls. North of the Hudson Valley is the Champlain Valley, to which two passages lead, one by way of Lake George and the other east of the Lake George pass by way of Southern Lake Champlain. The broader Hudson Valley and the Champlain Valley have been con- sidered the northeastward continuation of the Greater Appalachian Valley. SUB-LACUSTRINE OR SUB-MARINE GLACIAL DEPOSITS IN THE HUDSON AND CHAMPLAIN VALLEYS. In the bottom of the Hudson and Champlain Valleys there has been at built in recent geological times a plain mainly of clay, with margins frequently of gravel and sand." This plain has the form of an old | lake-floor or old sea-floor. The clay plain is best seen in the north- ern part of the Hudson from Catskill north. In the southern part of the valley—from Poughkeepsie south—it is either absent entirely, or is to be seen only in limited areas, and generally covered with gravel and sand. The clay in both the Hudson and Champlain Valleys is laminated, with alternate “fatty” and Sandy laminae having a thick- ness of one-fifteenth of an inch or more. (See Fig. 2.) The laminae are sometimes grouped into beds a few inches in thickness, sepa- rated by rather prominent lines of parting. In one place ripple marks were seen. (See Fig. 3.) The clay often shows faulting and frequently shows joint structure Conspicuously. (See Fig. 2.) It is sometimes contorted. The upper part of the clay is generally yellow in the Hudson Valley and brownish-red in the Champlain Valley. The # The clays and gravels and sands of the Hudson Valley have been described in considerable detail by F. J. H. MERRILL AND HEINRICH RIES in the Tenth Annual Report of the New York State Geologist, and by MR. RIES in the Bulletin of the New York State Museum, Vol. III, No. 12. The former report was in hand in the field, and while the interpretation placed on these deposits is quite different, the writer wishes here to make general acknowledgment of its aid in his studies. Specific acknowledg- ment is made in the proper place wherever this report has been drawn upon for facts beyond the writer's personal observation. The writer also had the aid in the field of the article by S. PRENTISS BALDWIN on “The Pleistocene History of the Champlain Valley,” American Geologist, Vol. XIII (1894), pp. 170–184. g 42O CHARLES EMERSON PEET lower part is blue. Bands and blotches of yellow often occur in the midst of the blue layers in the Hudson Valley. The clay often con- tains concretions. In thickness the clay varies from a small amount FIG. 2.-Showing joint structure in the laminated clay of the Hudson Valley. to 215 feet in the valley of the Hackensack and zero to 243 feet in the Hudson Valley, where it is commonly 80 to Ioo feet or more thick. In the Champlain Valley it is known to have a thickness as great as 60 to 75 feet, but is generally thinner than in the Hudson Valley. H. RIES, Bulletin N. Y. State Museum, Vol. III, No. 12, p. 184. GLACIAL AND POST-GLA CIAL HISTORY 42 I The clay overlies till (Fig. 4), gravel and sand, or rock ºl which are frequently striated. It fits into the irregularities of the till, or the stratified gravel and sand which sometimes appears to have the form of kames. In the upper Hudson the underlying stratified sand and gravel often has a high angle of dip, generally southward, but sometimes in other directions. These layers are interpreted as repre- senting deposits made by the ice waters in the standing body of water as the ice was retreating. This structure can frequently be seen from the car windows of the New York Central Railroad. The marginal FIG. 3–Ripple marks in the clay at New Windsor. deposits of gravel and sand have the form of plateaus of two distinct classes: Class I.-Gravel terraces and plateaus with undulatory topography on the edge toward the Hudson, which sometimes assumes a more or less kame-like or morainic form, or with the edge next to the Hud- son higher than the edge next to the valley wall, and with the dip of the layers of gravel and sand toward the valley wall and down- stream. This phase of the drift is the characteristic phase in the Highlands, and is not accompanied by a clay plain. Class 2.-The second phase of the stratified drift consists of gravel plateaus and terraces with the undulatory edge toward the 422 CHARLES EMERSON PEET valley wall, and the smoother and lower edge toward the Hudson." The inner and higher edge is sometimes marked by distinct kames or by moraine. The structure is delta-like. The layers usually dip at high angles toward the Hudson, and the coarse gravels and sands grade rapidly down the dip of the layers into fine laminated clay. (See Fig. 5, A and B, and Fig. 6.) In the clay and over the clay there are sometimes masses of till. (Fig. 4.) In the till there are sometimes masses of clay. Over the clay there often is coarse gravel with a subdued undulatory topography, and the contact of the Fig. 4.—Showing till both above and below the clay at Haverstraw. gravel and clay is of such a nature as to indicate that the gravel has been forcibly pressed against the clay surface. This phase of the gravel plateaus is the characteristic phase of the Appalachian Valley division of the Hudson Valley, and is usually associated with a wide clay plain. These two classes may be referred to as high-level ter- races. On the whole, they increase in altitude from south to north, but not at a uniform rate or continuously. They indicate a water 1 Some of the smoother plateaus may properly be called subaqueous overwash plains. See R. D. SALISBURY AND HENRY B. KüMMEL, Annual Report of State Geolo- gist of New Jersey, 1893, pp. 266-68; and R. D. SALISBURY, Glacial Geology of New Jersey, pp. 130–33. GLACIAL AND POST-GLACIAL HISTORY 423 body in the Hudson and Champlain Valleys as the ice was retreat- ing after making the Brooklyn-Perth Amboy moraine. Below the level of the high-level gravel plateaus there are two classes of deposits: (1) secondary deltas; (2) river terraces. The former have been recognized with certainty only in the northern Hudson. The latter occur in the northern Hudson Valley and in tributary valleys both in the northern and southern parts of the Hudson. In these lower terraces pebbles of clay occur rarely, evi- dently derived from the erosion of the higher clay deposits. :* # gº #*=se? *E. ă as *: º: * FIG. 5.-Diagrammatic sections: [A, of Haverstraw gravel plateau from west to east; B, of Newburg delta and moraine at the left and Dutchess Junction gravel plateau with morainic east edge on the right; C, a section similar to and about one mile south of D; D, Roseton on the left and the northern part of the Low Point deposits on the right. Par- allel horizontal lines represent clay. In the Hudson Valley this old sea- or lake-floor plain is naturally divided into three portions roughly corresponding with (1) the por- tion south of the Highlands, (2) the Highlands, and (3) the Hudson Valley north of the Highlands. Deposits in a lowland west of the Palisade Ridge will be described in connection with Division I. HUDSON VALLEY SOUTH OF THE HIGHLANDS AND LOWLAND WEST OF PALISADE RIDGE. From the narrows at Brooklyn northward to the Highlands the land rises gradually, as a slightly rolling upland, best represented by the even crest of the northern part of the Palisade Ridge, and by the 424 CHARLES EMERSON PEET level to which the hilltops reach east of the Hudson. Below the level of this upland to the west of the Palisade Ridge there is a low- land. Below the surface of this lowland too—150 feet there are FIG. 6–Photograph showing gradation of gravel and sand down the dip of the layers into clay, in the part of the Newburg delta north of the Quassaic. The work- man's shovel marks the point where one of the layers of gravel and sand at the left changes into clay. valleys” in which there are deposits of gravel, sand, and clay, pres- ently to be described. In the valleys in the southern part of this * New York City Folio, U. S. Geological Survey; Geography by R. E. DoDGE AND BAILEY WILLIS, p. 1. a Physical Geography of New Jersey, R. D. SALISBURY, p. 141. º IºIIE-ºv ºr Cº E-T- -AND *… L. C. L.N LTY Fig. 7-Model of New York City and vicinity. [Copyright by Edwin E. Howell; printed by permission.] 426 CHARLES EMERSON PEET lowland there are salt waters, which in their widest expanse consti- tute Newark Bay. (See Fig. I, No. 5, and Fig. 7.) The upland surface represented by the even crest of the Palisade Ridge is a remnant of the Cretaceous peneplain. The lowland sur- face represents a later peneplain developed on the softer rocks of the Triassic area." The valleys in this lowland represent erosion in pre-last glacial and post-Pensauken time. The stratified drift in these valleys was deposited largely by ice waters on the retreat of the ice from the Brooklyn-Perth Amboy moraine. Below the upland surface and at the east base of the Palisade Ridge is the Hudson Valley, now occupied by the waters of the Hudson estuary. Along the sides of the valley and below the waters of the Hudson estuary there are deposits of stratified gravels, sands, and clays similar in origin to those in the lowland west of the Pali- sade Ridge. Below the waters of the Hudson estuary and of Newark Bay there are certain submerged channels which are shown in Fig. 8 and will be referred to later. BROOKLYN-PERTH AMBOY MORAINE. Across the southern end of both the Hudson Valley and the low- land west of the Palisade Ridge there is the massive and complex ridge which forms the Brooklyn-Perth Amboy terminal moraine.” It is popularly referred to as the backbone of Long Island, and it also makes the more conspicuous elevations of the Southwestern part of Staten Island. Through this moraine there are two gaps—one at the south of the Hudson and the east end of Staten Island called the Narrows, and the other at the west end of Staten Island occupied by Arthur Kill. (See Fig. 8.) 1 This is called the Somerville peneplain by Professor W. M. Davis, and the pre- Pensauken peneplain by Professor R. D. Salisbury (loc. cit., pp. II4–15). 2 See R. D. SALISBURY, Glacial Geology of New Jersey, Chap. 9, and New York City Folio, U. S. Geological Survey. T. C. CHAMBERLIN, Third Annual Report, U. S. Geological Survey, 1881–82, pp. 377–79; WARREN UPHAM, American Journal of Science, 1879, pp. 81–92 and 179-209 : G. H. Cook AND J. C. SMOCK, Geological Survey of New Jersey, Annual Reports for 1877, 1878, and 1880. | %§§ \ºoºooºoººº. - FIG. 8.-Map of the drift and of the submerged channels of New York and vicinity [Taken from Plate 28 of R. D. Salisbury's Glacial Geology of New Jersey and from the New York City Folio of the U. S. Geological Survey. Some belts of thicker drift including kame belts and morainic areas are shown which were mentioned in the text of the former, but not included in Plate 28. On Long Island some belts are marked which were mapped partly as kames and partly as till areas. The submerged channels were traced from data obtained from the U. S. Coast Survey Charts.] LEGEND: A, belts of thicker drift including kame belts and morainic areas which are believed to mark halting places of the ice. B, areas of stratified drift with kames not included in A, and including some small areas of dune sand. C, mixed till and stratified drift. Till areas are shown in white, submarine channels in black. . . I, Raritan Bay; 2, Perth Amboy and Arthur Kill; 3, Woodbridge Creek; 4, Elizabeth River; 5, Newark Bay; 6, Passaic River; 7, Hackensack—city and river; 8, Englewood; Kill van Kull; Io, East River; 14, Sparkill Valley. s 428 CHARLES EMERSON PEET DRIFT OF LONG ISLAND AND STATEN ISLAND INSIDE THE BROOKLYN- PERTEI AMBOY MORAINE. Inside or north of the Brooklyn-Perth Amboy moraine a number of positions taken by the ice in its retreat are marked by moraines or kame belts, or other similar phenomena. Near the west end of Long Island at least two, and probably three, such belts are rep- resented more or less discontinuously. (See Fig. 8.) Possibly one such position is represented on Staten Island. DRIFT OF THE LowLAND west of THE PALISADE RIDGE AND NORTH OF THE BROOKLYN-PERTH AMBOY MORAINE. On the higher part of the lowland west of the Palisade Ridge and inside the Brooklyn-Perth Amboy moraine, there is an extensive series of belts of thicker drift, with more or less distinct morainic topography, or elongate belts of kames with the aspect of moraines, which are frequently bordered by plains of gravel and sand with the form of overwash or outwash plains. In some places such aggra- dation plains have no definite kame or morainic areas at their source. On the lower part of the lowlands there is a complex series of gravel and sand plains or plateaus, some of which head in kames, but others have ice-molded, but kameless, sources. Some of the plains have delta-like forms and delta-like struc- ures. The elevations of these plains at the south are 20–40 feett while farther north plains whose structure is unknown have eleva- tions of 80–100 feet." These deposits are found north from the latitude of Hackensack and Englewood well toward the northern border of the state. Underneath the gravel and sand of these plains, or spread out to the southward with little overlying sand or gravel, there is laminated clay which frequently has a thickness of Ioo feet and sometimes as great as 215 feet. This clay extends South of the latitude of Hackensack and Englewood, and is also found to the north.” I See R. D. SALISBURY AND C. E. PEET, “Drift Phenomena of the Palisade Ridge,” Annual Report of State Geologist of New Jersey, 1893, pp. 195–2 Io; and idem, “Drift of the Triassic Plain of New Jersey,” Glacial Geology of New Jersey (Final Report of State Geologist, Vol. V), Chap. 12, and especially pp. 506–13, 595-628, 632–42. 2The areal distribution of a large part of these deposits is shown in the maps of the New York City Folio, U. S. Geological Survey. See also Fig. 8 of this article. 6, 6- 6 6 6. e. 6, 6' 6' 6 9. FIG. 9.-Map showing some of the areas of stratified drift along the Hudson from north of Sing Sing to north of Camelot. LEGEND: A, moraines and kames, generally. In some places ice-shaped drift-forms that are neither moraine or kames are thus indicated. B, ice-moulded stratified drift. C, gravel plateaus made by ice waters. D and E, secondary deltas. F, clay chiefly, but other forms of stratified drift are included; knowledge is more certain where lines are not broken. G, approximate limits reached by the standing water. H, boundary lines showing approximate limits of the features inclosed. The white space next to the streams marks swamps, flood-plains, and low-level terraces. 14, Sparkill Valley; 15, Haverstraw and Minis- ceongo Creek; 17, North Haverstraw and Cedar Pond Brook; 18, Stony Point; 19, Jones Point; 20, Sing Sing (Ossining); 21, Croton Point and Croton River; 22, Croton Landing; 23, Oscawanna; 24, Crugers; 25, Verplanck’s Point; 26, Peekskill—village and creek; 27, Annsville; 28, State Camp; 29, Roye Hook; 3o, Highland Falls; 31, West Point; 32, Indian Brook; 33, Cold Spring and Foundry Brook; 35, Breakneck Mountain; 36, Cornwall; 37, New Windsor; 38, Newburg and Quassaic Creek; 39, Roseton; 4o, Marlboro; 41, Dutchess Junction; 42, Fishkill and Fish Kill; 43, Walcotville; 44, Carthage Landing and Low Point; 46, New Hamburg and Wappinger Creek; 47, Wappinger Falls; 48, Camelot; 49, Poughkeepsie. 43O * CHARLES EMERSON PEET DRIFT IN THE HUDSON VALLEY SOUTH OF THE HIGHLANDS AND NORTH OF LONG ISLAND AND STATEN ISLAND. The deposits of drift of special significance in this area occur north of Ossining (Sing Sing), where the valley begins to broaden out into Haverstraw Bay. Most of the deposits south of here are covered by the “Surficial Geological Maps” of the New York City Folio, and are mentioned in its text. The deposits of drift of special significance in this part of the valley belong to the two classes of high-level terraces mentioned above (p. 421). The features of Class I, similar to those found in the Highlands, are found (I) in a terrace at 120–Ioo feet A. T. from north of Sing Sing to south of Croton River mouth; (2) at Jones Point; and (3) features of similar import occur at Roye Hook near State Camp, Peekskill. These features are shown in Fig. 9, the first between Nos. 20 and 21, the second at No. 19, and the third at No. 29. To which class some of the features of a high-level terrace from Peekskill toward Osca- wanna belong is a question. (See Fig. 9, Nos. 23, 24, 25). The features of Class 2, similar to those prevailing in the Appalachian Valley part of the Hudson, occur at Croton Point and Croton Land- ing on the east side of the river, and from Haverstraw to north Haverstraw on the west side. (Fig. 9, Nos. 21, 22, and 15 and 17.) Haverstraw.—The deposits at Haverstraw of interest in connec- tion with this paper are of four types: (1) the narrow moraine at the foot of the Palisade Ridge; (2) a gravel plateau with undulatory topography and delta-like structure at an elevation of less than I2O feet A. T., which is underlain by (3) laminated brick clays, yellow in color above, and blue below; (4) low-level gravel, and clay. I. The moraine: The position of the ice-edge as it rested near the northern base of the Trap Ridge, which farther south makes the Palisades of the Hudson, is marked in the southern part of Hav- erstraw by a narrow moraine with a west-by-north and east-by-south trend, parallel approximately to the trend of the Trap Ridge. Where well-defined this moraine has a width of one-fourth to one-half of a mile. It has been traced for a distance of about two miles, from a point about one mile southeast of Thiell’s Station to within some- thing less than three-fourths of a mile northwest of Short Clove. It extends farther east in the form of a ridge, but with less definition GLACIAL AND POST-GLACIAL HISTORY 43I as Short Clove is approached. At its best the moraine shows a relief between hillocks and hollows of between 20 and 30 feet. (See Fig. 9, No. 15). Some of the hillocks are composed largely of strati- fied drift, but, So far as exposures show, a considerable part of the moraine is made up of till which is prevailingly of gneissic materials. There are places, however, where it shows a conspicuous red color from the abundance of Triassic constituents. 2 and 3. The Haverstraw gravel plateau has been called the Haverstraw delta. It extends from about the lower edge of the moraine above mentioned north- ward to Cedar Pond Brook, and descends from an elevation of a little less than I2O feet on the west to 40–60 feet on the east, where Fig. Io.—Cross-section of the Appa- it falls off abruptly to a lower achian Valley (after Pavis). g e e tº AB, uplands; CD, general valley lowland. Hori- plain bordering the Minisceongo zontaining shows. and Cedar Pond Brooks. - The topography of the plateau for the most part appears at first sight to be quite plain, with a general slope eastward and Southeastward. In the northern part, however, it becomes quite undulatory, and there are some depressions as great as 20 feet in depth, one of which is situated in a long conspicuous ridge extending north and South parallel to the road west of it, leading from West Haverstraw to North Haverstraw. This ridge is separated from the higher land to the west by a considerable trough-like hollow. On closer examination much of the surface, which at first sight appears to be quite plain, is found to be affected by ridge-like undulations and hollows with a relief of 6, 8, and Io feet These undulations extend eastward nearly to the abrupt east front. (See Fig. 5, A.) Structure and materials: Exposures are abundant in this plateau. In the higher western portion numerous gravel and sand pits show stratified sands and gravels more or less horizontal in the upper few feet, and dipping at high angles below in an easterly and Southerly direction. A little eastward these stratified gravels are said to over- lie clay, and still farther eastward exposures are of such a nature that it is quite certain that the gravels and sands grade into finer materials, and into clay with alternate layers of fine sand, and finally into the laminated brick clays. g tr * * j-. §§§§ * Kºź...Nº. 4 s 24Wºº SS ‘Sºs ºšš §§§ * 432 CHARLES EMERSON PEET While stratified materials appear to prevail in the capping of the clay, a number of places are to be found where the material is not stratified, and where it has the character of a compact till showing indications, at the contact with the clay, of having been subjected to a pressure which forced the clay and the till together. The contact surface is irregular. (Fig. 4.) The clay surface rises and falls as much as 2 feet in a distance of Io feet, while the layers of clay show contor- tion in the upper part. In earlier observations compact lumps of clay were noted in till-like material. Before it was firmly established that till overlies the clay, the writer did not feel sure that in the extraction of the clay for brick-making the lumps of clay had not become artificially mixed with till. It seems reasonably certain now, however, that the observed clay lumps in the till were not introduced artificially. Underlying the clay stratified gravel and sand was observed in some places with a topography which suggested buried kames. Flowing springs and flowing wells arising from this under- lying gravel and Sand indicate that the water has access to these porous layers at higher levels. 4. The low-level gravels are described below. North Haverstraw.—The gravel plateau at North Haverstraw very likely was once continuous with that described south of Cedar Pond Brook. It has a general elevation of something less than 120 feet A. T. On its west side, and a large part of its total area is Too feet A. T. It descends abruptly Ioo feet to the meadow along Cedar Pond Brook on the south, and on the northwest it descends abruptly to a plain at about 20 feet A. T. On the northeast the descent is to a kame-like gravel knoll at about 50 feet A. T. On the east there is a similar knoll. (Each of these knolls is indicated by a black circle at No. 17 in Fig. 9.) On the southeast the descent is to a terrace-like form at 40 feet, and farther South to a ridge of gravel of uncertain origin at 60 feet A. T. The west and northwest sides of the plateau have a gently undula- tory topography, and the surface of the plateau farther east has some ridge-like irregularities that suggest the presence of the ice during its deposition. Materials and structure: There are no good exposures in this conspicuous plateau, although exposures do occur in the lower gravel GLACIAL AND POST-GLACIAL HISTORY 433 forms to which the steep edges of the plateau descend. The indica- tions from the surface and from well data are that it is composed of gravel and sand. A well on the top of the plateau near the west side at the house of Mr. Neely is reported to have penetrated 120 feet of gravel and sand from an elevation of Ioo feet A. T. without reaching rock. The kame-like gravel knoll at the northeast edge of the plateau is situated South of the North Haverstraw Station of the West Shore Railroad. An exposure shows about 20 feet of coarse gravel. Far- ther south, east of the railroad, where the gravel likewise has a kame-like form, the layers dip north and south and east. North of these kames toward Stony Point clay occurs up to 40–60 feet, and has a form which may be due to erosion. -- Low-level gravel, and clay. What appear to be low-level terraces derived from the erosion of the higher gravels have been observed in the form of discontinuous shoulders on the north side of the Haverstraw gravel plateau on the slope to Cedar Pond Brook at elevations of 60 and 4o feet. A 40-foot level on the southeast side of the North Haver- straw plateau, and also a 60-foot level Southwest from the 40-foot level, may represent a product later in origin than the plateau itself. It may be said, however, that where the level of stratified drift varies so greatly as it does in this region it is not easy to determine posi- tively that the shoulders of limited area and uncertain relations are of later origin than the higher gravels, and do not represent remnants of undulations descending to the lower levels made while the ice was present. A wide plain extending along the water front from near Short Clove to Grassy Point, with an elevation by the topographic map of less than 20 feet A. T., has been so worked over in the making of bricks that it is difficult to say what was its original height and extent. Some exposures have been observed in it in which the materials included rounded pebbles of clay, evidently derived from the erosion of the higher level clays. In exposures near at hand and at about the same level the layers have a Southerly dip at a high angle, thus Sug- gesting lower-level delta deposits made from the erosion of the higher gravels and clay. At Grassy Point (south of No. 17, Fig. 9) there are deposits in this lowland which were made in the presence of the ice. No exposures which reveal the structure occur in the 60-foot and 434 CHARLES EMERSON PEET 40-foot levels south of Cedar Pond Brook. The 40-foot level at North Haverstraw is well exposed. In no part of the exposure was the delta structure seen which is so common in the high-level gravels, FIG. I. I.-The Catskills and the lowland in the Appalachian part of the Hudson Valley. [From A. P. Brigham, Geographic Influences on American History; courtesy of Ginn & Co.] and there is said to be no clay underlying the stratified gravel here for a considerable depth at least. Interpretation: (1) Ice present with its edge resting on the mor- aine at the foot of the Trap Ridge and with a general west-by-north and east-by-south direction on the west side of the Hudson. GLACIAL AND POST-GLACIAL HISTORY 435 (2) The ice retreated so that, either at one time or at successive positions, its edge occupied the Haverstraw and North Haverstraw gravel plateaus. (3) The ice waters discharged into a standing body of water and built up the deposits of gravel and sand, with the steep dipping layers of gravel rapidly grading into sand and then into clay. The clay was deposited on the irregular surface of the drift previously deposited. FIG. I.2.-Part of the Newburg delta, on the south side of the Quassaic. Looking West. (4) The ice, either by re-advances, or because of more favorable conditions in some places than in others while continually present, worked over the clays, producing some of the contortions observed, and involving masses of clay in the till which it deposited over the clay in favorable places. The water-worn gravel was in places brought under pressure, and the contact of the clay with the gravel was thereby made more intimate. (5) On the retreat of the ice and the fall of the water-level the higher-level gravels were eroded by the Minisceongo and Cedar Pond Brook, thus producing deposits at lower levels. Whether there are remnants of lower-level deltas cannot be confidently stated. They would naturally be expected. (6) After deeper erosion by the streams than the present Hudson level, submergence took place, thus drowning the mouths of the tribu- tary streams. 436 * CHARLES EMERSON PEET Croton.—On the east side of the river at Croton Point and Croton Landing, deposits of similar import occur, but not identical in detail, with those on the west side of the river. Lack of space forbids detailed description. Oscawanna—Crugers—Peekskill.—Clays and gravels: The clays and gravels in the city of Peekskill and south to Oscawanna show phenomena which in Some features are similar to, and in other features are unlike, those at Haverstraw and Croton. They are evidently deposits made later than the last-mentioned deposits. Their relations, however, to any marked and definite position of the ice-edge are not so well shown. The approximate area of these deposits is shown in Fig. 9 between Nos. 23 and 25. The deposits in this region are notable for their irregularity in level. The clay surface varies from an elevation approaching Ioo. feet A. T. to tide-level. It is in most cases covered with sand, or gravel, and in a broad statement it may be said that the finer materials predominate at the South, while at the north the materials overlying the clay include both fine materials and coarse gravels with bowlders up to five feet in diameter. In one or two instances till has been found overlying the clay in this region. The structure of the stratified materials overlying the clay even at high levels does not generally show the high angle of dip so common in the high-level gravels at Haverstraw and Croton. The high-level terrace has an elevation of Ioo-I2o feet A. T. Parts of it, however, reach lower levels—60–80 feet A. T., and per- haps less. It is somewhat difficult to discriminate between what may properly be called high-level terrace and what may properly be called low-level terrace. Terraces at low levels exist at 60, 40, 30, and Io–20 feet A. T. In general, these terraces are covered by gravel and Sand. The gravel is sometimes very coarse, containing bowlders as large as five feet in diameter. The relations to the clay are not always distinguishable. It is not an uncommon relation, however, to find these low-level gravels much lower in level than clay in the immediate vicinity. It is questionable, however, if in all cases this relation has been brought about by the erosion of the higher-level deposits. It is conceivable that some of the low-level deposits are original deposits by the ice water, which simply failed to build up at SA FIG. I.3.−Showing principal areas of stratified drift along the Hudson from latitude of South Schodack to north of Saratoga Springs. LEGEND: A, moraines and kames, generally. In some places ice-shaped drift-forms that are neither moraine or kames are thus indicated. B, ice-molded stratified drift. C, gravel plateaus made by ice waters. D and E, secondary deltas. On the Batten Kill some of the ice-water deposits may be included in the areas covered by this device. F, clay chiefly but other forms of stratified drift are included. Knowledge is more certain where lines are not broken. G, approximate limits reached by the standing water. H, boundary lines showing approximate limits of the inclosed features. The white space next to the streams marks swamps, flood-plains, and low-level terraces. - 62, South Bethlehem, Sprayt Kill and Oniskethau Creek; 63, New Scotland; 64, Voorheesville; 65, Newtonville; 66, Schenectady; 73, South Schodack; 74, East Green- bush; 75, Teller Hill; 76, Troy; 77 Mechanicsville; 78, Ballston Lake; 79, Round Lake; 8o, Maltaville; 81, Saratoga Lake; 82, Ballston Spa; 83, Lonely Lake; 84, Saratoga Springs; 85, Moreau Pond; 90, Hoosic River; 91, Batten Kill; 92, Fort Miller; 93, Moses Kill. 438 CHARLES EMERSON PEET these particular places to the level reached in adjacent places. It may be said that this relation is more clearly shown by phenomena seen elsewhere. The facts in this locality are sufficiently doubtful, at any rate, to justify caution in asserting the erosion origin of the irregularities in the clay. However, there are some facts which seem to indicate a considerable amount of erosion of the clay in this region and subsequent deposition of gravel in the clay channels. Jones Point and State Camp near Peekskill.—At Jones Point a narrow terrace less than a mile in length occurs on the right side of the Hud- son. It is made up mainly of stratified gravel and sand and a little clay. Formerly it contained more clay." The terrace has an elevation at its north end of about IOO feet A. T., and at its south end of about 60–80 feet, and at present, in places at any rate, is higher toward the Hudson than toward the valley wall. See Fig. 9, No. 19. At State Camp (28) near the mouth of the Peeks Kill there is a gravel plateau with an elevation of Ioo feet A. T. whose flat top is used by the New York state militia as a camping and parade ground. This plateau continues up the valley of Sprout Brook with some breaks, to a point about one mile northeast of Annsville (27), where it has an elevation of I40–160 feet A. T. It was not studied beyond this point. It also extends northward up the valley of the small tribu- tary north of State Camp and southeast of Wallace Pond. Its greatest development occurs, however, at State Camp on the right bank of Peeks Kill. A small remnant occurs farther upstream on the left bank. While the plain surface as a whole rises upstream, the northern portion of it at State Camp slopes eastward—a fact of some significance perhaps in determining the history of the plateau. The exposures in this plateau show gravel overlying clay. The clay reaches higher above sea-level near the extremity of the plateau than farther upstream, thus indicating a gradation of Coarse materials from upstream into the fine clay. Low-level terraces occur farther downstream on both right and left sides of the stream at 30–40 feet A. T. Roye Hook.-West of the plateau near the State Camp Station of the New York Central Railway there is an isolated hill of small dimensions, reaching an elevation of Ioo feet A. T. This is called 1 See H. RIES, Tenth Annual Report State Geologist of New York, p. 114. GLACIAL AND POST-GLACIAL HISTORY 439 Roye Hook (29, Fig. 9). At its base, both on the north and on the south, there are low-level terraces at about 30 feet. In the Roye Hook hill a large gravel and sand pit shows about Io feet of fine sand and gravel overlying 5 feet of silt, both sand and silt being hori- zontally stratified, or nearly so. But under the silt there is about 85 feet of coarse gravel and Sand, with layers dipping at a high angle eastward and southeastward. The gravel and sand in this lower portion of the exposure were not observed to grade into clay, as they were observed to do at Croton, and as they apparently do at Haver- straw. The phenomena at Jones Point and Roye Hook are more nearly allied to deposits which occur in the Highlands than they are to those that occur in the broader part of the valley to the south. These characteristics are discussed in the description of the Highlands phe- I) Oſſleſla. THE HIGHILANDS OF THE HUDSON. As indicated above in the description of the general features of the Hudson, south of Newburg and Fishkill the Hudson leaves the Appalachian district and crosses through the plateau to the South in that part of its course designated the Highlands of the Hudson. The features of the rock valley here differ radically from those at the north, and in place of a broad dissected lowland between distant uplands, like that in the Appalachian Valley, or of the broad amphi- theater between distant uplands like that at the north edge of the Palisade Ridge at Haverstraw, we have the upland descending abruptly from elevations of I, Ioo and 1,400 feet to the waters of the estuary, which is here generally from four-fifths to seven-tenths miles wide, and reaches a maximum width of one and three-fifths miles. In this narrow valley the gravel plateaus are present, but if there is a clay plain, it is covered by the waters of the estuary, or is represented by a few limited remnants only. The gravel plateaus in the Highlands of the Hudson have charac- teristics which are typical of Class I above described, and indicate the presence of the ice in the valley while these deposits were accumu- lating. There are situations however, where streams of water came from the ice outside of the immediate Hudson River valley and deposited their loads on slopes toward the center of the valley. Such 44O CHARLES EMERSON PEET phenomena occur where streams headed north from their debou- chure, and are represented, it is believed, by a part of the State Camp deposits on the southern edge of the Highlands. The gravel plateaus of the Highlands that were examined are (I) at West Point and south toward Highland Falls (30); (2) at Cold Spring (33) and south toward Garrison. The stratified drift at Roye Hook near State Camp, per- haps part of the State Camp plateau where the surface slopes east- FIG. I.4.—Looking across the clay plain of the upper Hudson. [Photograph by W. S. McGee.] ward, and the Jones Point plateau, on the southern edge of the Highlands have characteristics similar to those in the Highlands and indicate a similar position of the ice in respect to the valley when they were building. North of West Point in the Highlands there is little left of any former valley filling, if the valley ever was filled. One or two miles south of Storm King, on the right bank of the Hudson, a remnant of clay in a terrace form was observed at an elevation estimated at 60 feet, and nearer Storm King another remnant was observed. On the left bank there are several remnants of clay or gravel, the most conspicuous of GLACIAL AND POST-GLACIAL HISTORY 44 I. which is a terrace of coarse gravel on the south side of Breakneck Mountain (35, Fig. 9) with an elevation estimated at 80 feet. The weight of evidence in this part of the Hudson indicates that the ice protruded as a tongue down the valley, and that it was influential in shaping the edge of the plateaus toward the Hudson. An alternative hypothesis is that the ice retired in a northeasterly direc- FIG. I5–Looking eastward from the bluffs north of Albany across the trench of the Hudson, cut into the clay plain. tion; that the plateaus on the west side of the valley were made first and had their east edge shaped by the ice-front; and that later those on the east side of the valley were constructed and had their east edge shaped by the ice. This alternative hypothesis, however, does not explain the eastward-dipping layers of the plateaus on the east side of the valley, nor does it explain the apparent lower elevation of some parts of the terraces on the east side next to the valley wall. It would explain successive undulations from lower levels near the Hudson to higher levels away from the Hudson, such as are found at Cold Spring (33, Fig. 9). 442 CHARLES EMERSON PEET HUDSON VALLEY NORTH OF THE HIGHLANDS. The valley north of the Highlands has been considered the north- eastward continuation of the Greater Appalachian Valley. It lies between the upland surface on the east, which in New England is called the New England Plateau, and on the west it is limited by the Alleghany Front which is the steep slope from the Alleghany Plateau to the Greater Appalachian Valley, a part of the dissected edge of which is called the Catskill Mountains. Below the level of these eastern and western plateau surfaces is a broad lowland. Below the level of this lowland surface there are deep valleys. In the bottom of these valleys there are the deposits of stratified drift which have the form of an old lake- or sea-floor. Below this old lake- or old sea-floor are valleys and other depressions. In the bottom of the Hudson Valley are the Hudson and its estuary, beneath the waters of which is the submerged channel described below. In this region and farther to the Southwest, upland and lowland surfaces in the Appalachian district have been interpreted as representing peneplains at two or more levels." The interpretation of the pre-glacial history of the valley is beyond the scope of this article. The writer wishes to get before the reader a general picture of the region only, without refer- ence to the pre-glacial history. (See Figs. Io and II). In the Appalachian part of the Hudson the drift phenomena may be described in seven sections: (1) the Fishkill-Dutchess Junction (Fig. 9, Nos. 42, 41), and Newburg-New Windsor deposits (38, 37); (2) high-level terrace north of Fishkill (south of 44 and north of 42); (3) deposits from Carthage Landing to Low Point on the east side of the Hudson and at Roseton on the west side (Nos. 44 and 39); (4) New Hamburg gravel plateau and stratified drift on Wappinger Creek (Nos. 46 and 47); (5) Camelot kames (No. 48); (6) deposits north of Camelot from Poughkeepsie to Catskill; (7) deposits from north of Catskill to north of Glens Falls (Figs. I3 and 18). The deposits in Division I are similar in import to those in Division 7, and are very much like the phenomena at Haverstraw and Croton. * See R. D. SALISBURY, Physical Geography of New Jersey, pp. 8–14, 83–85, 94– 98; BAILEY WILLIS, “Northern Appalachians,” National Geographical Society Mono- graphs, Vol. I; C. W. HAYES, “Southern Appalachians,” ibid., and W. M. DAVIs, Pro- ceedings of the Boston Society of Natural History, Vol. XXV (1891), pp. 318 et seq. GLACIAL AND POST-GLACIAL HISTORY 443 The phenomena in Division 2 are somewhat like those from south of Peekskill toward Oscawanna, and indicate the presence of the ice in the valley near the north edge of the terrace when the deposits found here were being made. The Carthage Landing-Low Point and Roseton deposits indicate the presence of the ice in the valley when adjacent stratified drift at higher levels was accumulating. The New Hamburg gravel plateau and Wappinger Creek stratified drift indicate the presence of the ice in the valley at the edge of the New Hamburg plateau while the ice in the higher lands was retreating through the Wappinger Creek Valley. s I. NEWBURG-NEW WINDSOR AND FISHKILL-DUTCHESS JUNCTION. These places are situated on opposite sides of the river. On each side the Haverstraw phenomena are repeated. Gravel plateaus under- lain by clay are situated next to the river, and morainic phenomena occur on the higher land away from the river. The gravel plateau at Newburg is more delta-like in form than either at Haverstraw or Fishkill-Dutchess Junction. (See Fig. 12.) In the latter places the surface is marked by undulations similar in kind to, but more sub- dued than those in the moraines on the adjacent higher land. Masses of till are found at Dutchess Junction in the clay. At one place ripple marks were found in the clay at New Windsor. (See Fig. 3.) Interpretation: The interpretation of these deposits is similar to that of the Haverstraw deposits. It is difficult to see how the ice of a single ice-lobe can retire from a valley both to the eastward and to the westward, either simultaneously or successively, unless it be by the making of an embayment in its front. The evidence here, like that at Croton Point and Haverstraw, points to an embayment of the ice-front with at least wings of ice extending farther down the Hudson on each side. If the interpretation of the Jones Point, Roye Hook, and West Point-Cold Spring phenomena be correct, it would seem that the front changed from a protruding tongue in the Highlands and immediately south, to an embayment at Newburg-New Wind- Sor and Dutchess Junction-Fishkill. This is similar to the inter- pretation of a protruding ice tongue South of Croton Point and Haverstraw and an embayment at those places. The level to which the waters of the Hudson water body reached 444 CHARLES EMERSON PEET seems to be 140 feet. It may have reached somewhat higher. The only means of determining this limit seems to be the maximum limit of the delta structure. The presence of kames or moraine does not fix an upper limit to the water, as indicated by the North Haverstraw kame-like bodies at low levels, and by kames at Camelot and other places to be mentioned hereafter. - Low-level terraces on the Fishkill and Quassaic have the same import as those at Croton. It is a question how much erosion has taken place in the Hudson Valley itself. If the ice was on the valley sides and the waters discharging into the valley which was free from ice, it would be expected that the valley would be filled entirely across up to the level required by the slope of the deposits from each side. Since the clay would naturally take a very gentle slope if the valley was free, it would be expected to fill to a height somewhat less than the height of the clay on each side, but not very much less. Alto- gether it seems probable that the erosion here has been more than Ioo feet, while in regions immediately north it is very much less than this. II. EIIGH-LEVEL TERRACE NORTH OF FISHKILL. One and one-quarter miles north of Fishkill a sand-and-gravel- capped clay terrace at Ioo feet at its outer edge and I2O feet at its inner edge extends northward for about one mile, with a width of less than one-quarter of a mile up to three-quarters of a mile. The overlying gravel and sand have a depth of 6–Io feet, and the layers dip south. Near its north end gravel and sand occur at a higher level, with a slightly undulatory topography, which may mark the ice-edge on the land when the terrace was building in the Hudson water body. (See Fig. 9 South of No. 44 and north of 42.) III. CARTHAGE LANDING-IOW POINT AND ROSETON. At the northwest margin of the above-mentioned IOO–120-foot terrace a lower terrace of gravel-capped clay occurs at 20–40 feet A. T. The clay in this terrace varies in elevation from Sea-level or below to 40 feet above sea-level. The gravel above the clay is Coarse and contains some sink-like depressions. (Fig. 5, C.) It extends from a point one and one-quarter miles South of Carthage Land- GLACIAL AND POST-GLACIAL HISTORY 445 ing to a point three-quarters of a mile north of that place. For a half mile at its Southern end it borders the undulatory gravel area mentioned above in connection with the Ioo-I20-foot terrace. Nearer its north end it is separated from a higher deposit of sand-capped clay by a till area which has a slightly undulatory topography. (Fig. 5, D.) Opposite this low terrace, at Roseton and north toward Danskammer Light, a gravel-capped clay deposit occurs at a slightly higher level, with a terrace form. There are two hypotheses to explain these relations: (1) The deposits at Roseton once extended entirely across the valley and have since been eroded, and the 20–40- foot terrace is the product of erosion of the higher deposits. (2) The Second hypothesis is that the Roseton gravel-capped clay terrace and the high-level clay deposit on the east side of the Hudson were never continuous, but that the ice occupied the valley when they were made, and stood on the 20–40-foot gravel terrace, but failed to build it as high as the Ioo-I20-foot terrace to the south, or the Roseton terrace to the west and the clay to the east. The sinks in the 20–40-foot terrace, and the faint undulations in the till on the slope between the 20–40-foot terrace and the higher clay, bear this out. If this is the correct interpretation, it is a case similar in kind to the kame-like knolls near the North Haverstraw gravel plateau, and also like he phenomena just south of Peekskill near Verplancks. Under this interpretation the 20–40-foot terrace may or may not once have extended entirely across the valley. Under the first hypothesis both the high-level and the low-level terraces formerly extended entirely across the valley. It may be objected to the second hypothe- sis that when the ice had retired to New Hamburg, and the clays and Sands and gravels were accumulating, some of the finer mate- rials at least should have been carried south into this unoccupied part of the valley. This argument would be especially strong if the Hudson water body was subject to tides whose ebb would tend to carry the fine detritus down into this space. It is, however, not at all necessary to believe that the valley between these two terraces was unoccupied at this time. If the valley was occupied, it was by a mass of stagnant ice. There is evidence elsewhere that such masses of stagnant ice were left in the valley. - 446 CHARLES EMERSON PEET IV. NEW HAMBURG GRAVEL PLATEAU AND WAPPINGER CREEK STRATIFIED DRIFT. A gravel plateau occurs at New Hamburg (46), which has a width in a north-south direction of about one-half mile, and connects with stratified drift which extends upstream to the northeast four miles or more, and spreads out to broader dimensions. It has an eleva- tion at its west edge of Ioo feet A. T., and a plain surface which rises upstream, and at Wappinger Falls (47), at an elevation of I40 feet A. T., it has a topography which indicates the presence of ice. Farther northeast kames occur in small areas. The edge of this plateau is steep at the northwest side, but farther south, and east of New Hamburg village, it falls off in undulations, which indicate the presence of the ice during its formation. Exposures in this plateau in this lower portion show layers of gravel and sand with dips west in the western part, and east in the lower portion of the eastern part. Apparently this gravel and sand grades into clay farther east. It will be noted that this would be upstream as the Wappinger Creek now flows. The easterly dipping layers are interpreted as the fore-set beds (of Davis) and the clay as the bottom-set beds. The westerly dipping layers are interpreted as the back-set beds. Farther upstream, just east of the print mills, near the point where the surface topography indicates the co-operation of the ice in forming the plateau, gravel and sand in considerable thickness overlie silt and yellow clay which reach 6o feet A. T. or more. Blue clay was observed farther south on the left bank of the Creek. The layers of gravel and sand dip west and southwest. Low-level terraces: In the village of Wappinger Falls a lower terrace at 40–60 feet is to be seen, and also one at 20 feet. Both are made of gravel with pebbles 2–3 inches in diameter. Farther down stream a terrace occurs at 30 feet A. T. V. CAMELOT KAMES. Near Camelot kames unassociated with a gravel plateau occur in a valley tributary to the Hudson within 20–40 feet of sea-level, and in the immediate Hudson Valley within 60 feet of sea-level. (Fig. 9, No. 48.) GLACIAL AND POST-GLACIAL HISTORY 447 VI. NORTH OF CAMELOT TO NORTH OF CATSKILL.” From north of Camelot to Catskill the study of the deposits was made largely in passage, so that the relations of the deposits to the successive positions of the ice-edge cannot be stated. These fugitive observations indicate a general higher altitude of the deposits next to the valley side and a lower altitude next to the Hudson. They also indicate an alternate increase and decrease in the elevation both in the present Hudson bluffs and farther back from the river, and this is interpreted as indicating more than one stand of ice in this area. South of Poughkeepsie is a pitted plain at 140 feet A. T. with a steep descent toward the Hudson. The origin of this descent is unknown. Gravel was observed at various points along the West Shore Railroad from West Park to Ulster Park, at elevations of Ioo and I4o feet A. T. Clay was observed nearer South Rondout at I40 feet, and in South Rondout clay underlies sand which has an elevation of 150 feet. At Kingston along the Hudson a sand-capped clay terrace occurs 220 feet A. T., while farther west along the West Shore Rail- road a plain at 180–200 feet A. T. is coated with sand and gravel that are said to be underlain by clay. North of Kingston the clay has an elevation of IOO–14o feet in the Hudson bluffs, and a higher elevation west of the bluffs, where sand covers the surface. At Glasco the clay has an elevation of 140 feet in the river bluffs and 180 feet along the West Shore Railroad two and one-half miles to the westward. At Saugerties and north toward West Camp it has an elevation of 140–160 feet. At Catskill it has an elevation of IOO–120 feet, and a plain surface which has been trenched by the Catskill and its tributaries. It has been described here by Professor W. M. Davis, who has also described the delta of the Cats- kill.” VII. NORTH OF CATSKILL TO NORTH OF GLENS FALLS. Old lake-floor or old sea-floor.—In the Appalachian Valley part of the Hudson north of Catskill, and perhaps from north of Pough- keepsie the first approximation to a correct picture of the topography I For places mentioned in this division see Fig. I. 2 Proceedings of the Boston Society of Natural History, Vol. XXV (1891), pp. 318–35. 448 CHARLES EMERSON PEET is that of a plain descending gradually from the valley sides to the bluffs (of clay generally) bordering the present Hudson. The eleva- tion, on the whole, increases from the south, where it is Ioo or 120 feet to 180 feet, toward the north, where it is 220–240 feet along the bluffs of the present Hudson. From these elevations marking the bottom of the trough or the meeting of the slopes of the sea- or lake-floor, the plain rises eastward and westward to the higher land marking its limits. (See Fig. I4.) - Gravel plateaus and deltas.-Above the plain on the east and On the west rise gravel plateaus, some of them delta-like in form, which represent approximately the level of the waters when the floor above described was being built up. These gravel plateaus and deltas are found at the following places: On the left bank—(1) South Schodack and northwest at 340–360 feet; (2) Troy, 300 and 360 feet (?); (3) Hoosick River, 360 and 280–300** (?) feet; (4) Batten Kill, 380–400 (?) and 300” feet; (5) At Glens Falls and vicinity, 460 (?), 389, 34o”, and 280–300* feet. On the right bank—(1) South Bethlehem, at 300, 240°, and 200–220° feet; (2) at Maltaville, 340–360 feet; (3) at Saratoga and vicinity, 400 (?), 320–340, 300, and 260 feet; (4) Southwest of Glens Falls, 34o” and 38o feet—a continu- ation of the Glens Falls levels of the left bank. The plateaus descend abruptly toward the plain. The layers of coarse gravel and Sand of which they are generally made may some- times be seen to dip at high angles in the same direction and to grade down the dip into the fine materials, and into the clay which makes up a large part of the plain. They are like those of Class 2 of the lower Hudson. The height of the gravel plateaus above the level of the floor varies from I60 to 180 feet on the north to IOO–12o or I4o feet in the southern part of this area. While these gravel plateaus descend abruptly toward the old lake- or old sea-floor, and the stratification bears the significant relation to the clay plain mentioned above, the relation of the gravel plateaus up the slope of their surface is just as significant. When traced back they are found to connect, r The stars indicate secondary deltas. Perhaps the 3oo-foot Troy delta should be considered secondary. Perhaps a part of the 3oo-foot delta on the Batten Kill is not secondary. It has been seen only in its northern part. Its Southern part as rep- resented on Fig. 13, No. 91 is hypothetical. GLACIAL AND POST-GLACIAL HISTORY 449 (I) with valley trains leading down from positions marking the ice- edge during its retreat: or (2) they head directly in kames or other morainic developments which are just as significant in showing the relation of the gravel plateaus to the source from which the material was derived, and from which emanated the waters that transported the delta materials to their present resting place. These kames and moraines have been traced back from the immediate Hudson Valley in a few cases, and have been seen to develop into fairly well-defined morainic topography, while in the lower lands the morainic phenom- ena are more subdued. Such kames and moraines are found at the following places: (1) At the eastern and northeastern margin of the South Schodack gravel plateau. The East Greenbush kame area makes a part of this belt. (See Fig. I 3, Nos. 73, 74). (2) The Teller hill kames (No. 75), which are fronted by clay without an - intervening gravel plateau. (3) The line of kames and moraine extending from North Albany to Newtonville (No. 65). (4) Kames at Troy (No. 76). (5) Glen Lake-Hopkins Pond kame belt north of Glens Falls (Fig. 18, Nos. 87 and 89). (6) Kames between New Scot- land and Voorheesville (Fig. I3, Nos. 63 and 64). (7) Kames at Saratoga Springs (Fig. 13, No. 84). (8) The Moreau Pond belt of kames (No. 85). That the relation of this kame belt to the gravel plateau east of it is similar to the relation of the kames and gravel plateaus mentioned above, is not certain. m The surface of the gravel plateaus is sometimes marked by ridges or by deep sinks. The clay plain at the outer edge of some of these plateaus has a higher level than at the same edge of the plain farther north, or the reverse may be true. The clay plain sometimes fronts kame areas without an intervening gravel plateau, and the top of the kame area may be lower than the level of the gravel plateau immedi- ately adjacent. On some of the streams, notably the Hoosick River, deltas occur without the undulatory surface. From north of the lati- tude of Mechanicsville to the northern part of Saratoga Springs, the western part of the lowland is occupied by a succession of gravel plateaus (area 50–75 square miles) with discordant levels, which are Separated by depressions having a general northeast-southwest direc- tion, and in the bottom of which are lakes such as Round Lake, Saratoga Lake (with a length of 5–8 miles and a width of 2 miles), 45O CHARLES EMERSON PEET . l and Lonely Lake. Probably Ballston Lake is thus situated. (See Fig. I3.) • Under Several of these gravel plateaus, over wide areas, clay is reported. In the bottom of the Round Lake depression there is till, and a limited coarse gravel area with deep sinks in it, although clay and stratified drift rise in steep faces to the north and to the west, and perhaps in other directions. It is believed that these northeast-southwest depressions were occupied by masses of stagnant ice while subsequent plateaus to the northwest were being built, and that the northeast-southwest trend of the depressions indicates some- thing of the direction of the ice-edge as it retreated. At Glens Falls and north a succession of gravel plateaus is believed to mark the successive positions of the ice-edge in a similar way, but they are not separated by wide depressions, or depressions of any kind so gen- erally. Below the level of these gravel plateaus are secondary deltas derived from higher gravels by erosion. It is believed that they have been recognized at South Bethlehem (two levels—one on Sprayt Kill and one on the Oniskethau) (Fig. 13, No. 62), on the Hoosick River (Fig. I3, No. 90), on the Batten Kill near Schuyler- ville (Fig, 13, No. 91), and on the Hudson in the vicinity of Glens Falls (two levels) (Fig. 18, Nos. 94 and 86.) Elevations above old lake- or old sea-floor.—Above the plain in situations not confined to its borders there rises another class of eleva- tions, some of which were islands in the sea or lake, when the gravel plateaus and deltas were being made. These hills sometimes are drift hills. More often they are drift-covered rock hills. Such islands may be seen in the following places: * (I) hill northeast of Saratoga; (2) highland east of Saratoga Lake; (3) hills north and south of Mohawk River; (4) hills Southeast of Albany; (5) hills south of New Baltimore and at numerous places southward, where the elevations are ridges elongate in a north-South direction. Some of these hills may have formed shallows only, at the highest stage of the Hudson water body, but most of them were distinct islands and served to break the water body up into Several more or less separate portions. There were doubtless other shallows or islands, and the elevations * See also WARREN UPHAM, American Geologist, Vol. XXXII (1903), pp. 223–30. 2 For these elevations see Fig. 13. GLACIAL AND POST-GLACIAL HISTORY - 45I that made shallows at the highest stages of the water body must have produced islands and peninsulas at lower stages. Depressions below old lake- or old sea-floor.—Below the level of the sea-floor or lake-floor plain there are two classes of depressions: (I) lake basins and similar depressions not occupied by lakes; (2) valleys produced by erosion. The depressions occupied by lakes are those like the Saratoga Lake basin and Round Lake basin, the origin of which has been referred to above and will be discussed below. The basins may be small—a few yards across and shallow; or they may be like the basin of Saratoga Lake, 5–8 miles in length and 4–2 miles in width, and with a depth below the plain surface of 60–100 feet, plus the depth of the water in the lake. The second class of depressions below the old lake- or old sea-floor are the valleys of the present streams, of which the Hudson is the chief. (Fig. I5.) Below Troy the Hudson is now an estuary, but above that place the tide does not reach. The course of the Hudson is inter- preted as marking the trough of the depression down to which the old sea- or lake-floor sloped from each side, and which was followed by the main stream when the floor emerged from the waters in which it had been built. Some of the details in the course of the Hud- son may be explained as due to the greater building out along one side of the lake or sea, as for example the westward bend of the Hudson opposite the mouth of the Hoosick River, where the building out of the delta from the eastern side of the valley crowded the depres- sion farther out into the midst of the plain than to the north or to the south beyond the influence of the delta deposits. This westward bend amounts to about two miles. There is no doubt that similar explanations will account for the fact that the Hudson is nearer one side of the valley than the other in different portions of its course, and for other details; but it is probable that other slopes of the floor were the resultant of the interaction of several factors—the original topog- raphy of the valley, the rate of deposition by the agencies building up the floor, and the length of time the building continued. At any rate, the course of the Hudson may be considered a consequent course determined by the slopes of the old lake- or old sea-floor across which it flowed when the floor emerged from the lake or sea that had occu- pied it. Since that time it has trenched its course below the level of 452 - CHARLES EMERSON PEET the plain I50–170 feet north of Athens, 190–200 feet at Albany, and 8o feet near Fort Edward. This channel is now covered by tide- water to a depth varying from IO-25 feet at Albany to 15–50 feet north of Athens. This depth of water is included in the above esti- mates of erosion, from Albany south. - The tributaries of the Hudson have courses that are as significant as that of the main stream itself. The larger streams and the longer small streams that head in the country beyond the limits of the plain and above the level of the Hudson water body descend in general by rather steep slopes to the plain, Cross the plain on gentle gradients and descend abruptly near their mouths to the Hudson (Fig. 16, A). On A T- - - FIG. I.6. A, profile characteristic of streams tributary to the upper Hudson, or flowing either into the Poultney- Mettawee or Fort Edward Valley; B, profile characteristic of streams crossing the clay plain and flowing Into northern Lake Champlain. the smaller streams in general this steep slope is not far from the Hud- son, and on the larger streams in general it is less abrupt and is farther back from the Hudson. The courses of these streams like that of the Hudson have been determined with few exceptions by the topography of the old lake- or old sea-floor, and one may picture the streams as extending their courses across this floor following the slope of the land as the Hudson water body receded. To these consequent streams Subsequent tributaries have no doubt been added, and to the Original Consequent character of the stream gradients has been added the steep gradient found at the mouth of so many of the streams. The full explanation of this will be taken up later, but it may be said here that this steep gradient is due to so rapid a cutting down of the valley of the Hudson that the smaller and weaker tributaries were unable to keep pace with it. The reason for this will appear later. In some cases the failure of the tributaries to keep pace with the Hud- Son in its downcutting is due partly to the disadvantage of a hard rock-bed, with which the Hudson did not have to contend. GLACIAL AND POST-GLACIAL HISTORY 453 SUBMERGED CHANNEL OF THE HUDSON. The submerged channel extends from Troy, the limit reached by the tides, through the Narrows of Brooklyn and beyond out to the outer edge of the overwash plain fronting the Brooklyn moraine. Beyond this there are a number of channels, but none can be Con- sidered a continuation of the channel through the Narrows until opposite Sandy Hook, where a channel begins that can be traced southeastward to the forty-one-fathom line. (See Fig. 17.) Whether this should be considered a continuation of the Narrows channel will be discussed later. . Extra-morainic channel.—This channel can be traced from a point opposite Sandy Hook South- eastward and ends at the forty- one-fathom line,” eighty nautical miles from Sandy Hook. In depth below the plain into which it is cut it varies from zero to 90 feet. FIG. I.7.-Submerged extra-morainic Tenmiles from Sandy Hook it has channel of the Hudson. a d epth Of 48 feet, and incr CalSCS G, shallower channel to forty-one fathom line; 5 H, deeper channel. [Taken from map by A. south-eastward to 90 feet, and Lindenkohl in the U. S. Coast and Geodetic Survey again decreases to zero feet, at the Report for 1884.] forty-one-fathom line. Beyond this channel, after an interval, there is a much deeper ravine, with which this paper is not concerned. It is 25 miles long, 3 miles wide, and has a maximum depth of 2844 feet.” Channel inside the moraine.—The channel inside the moraine is covered by the waters of the Hudson estuary which vary from Io to 216 feet in depth. On the whole, the minimum depth increases from Troy to just north of Newburg. South of here the water is shallow to the Highlands. In the Highlands it is deep, and from North Haverstraw South it is shallow again, but on the whole grows deeper to the Narrows. Throughout its entire length there is a very great variation in the depth, however. There are certain “deeps” which *A. LINDENKOHL, American Journal of Science, Vol. CXXIX (1885), pp. 475–80. 2 LINDENKOHL, loc. cit. 454 CHARLES EMERSON PEET * vary from a maximum of 216 feet at West Point to 120 feet and less (See Fig. 8 for the submerged channels near New York city.) WAVE-WE&OUGHT IFEATURES IN THE HUDSON VALLEY. There is an entire absence of wave-wrought features in the Hudson Valley, so far as known, with the possible exception of some gravel ridges on the low-level delta at Fort Edward east of Glens Falls, and some indistinct terraces on the west side of the valley south of Ballston. * Bl]RIED SOILS. An old soil with an elevation close to sea level has been observed on the clay surface South of Hackensack. It is overlain by ten feet of sand, the lower part of which contains clay a few inches in thick- ness, associated with fragments of leaves and woody stems. The soil is leached to a depth of one foot." On the east side of Newark Bay, south of the Lehigh Valley Rail- road, a bed of peat or peaty soil is buried by Io-3o feet of sand, much and perhaps all of which is a wind deposit.” FOSSILS IN THE HUDSON VALLEY, AND IN THE LOWLAND WEST OF THE PALISADE RIDGE. The only fossils that have been found in deposits of the Hudson water body in the Hudson Valley are: (1) Sponge spicules, fresh- water diatoms, and worm-tracks at Croton;3 and (2) leaves of Vaccinia oxycoccus at Albany." In the lowland west of the Palisade Ridge, near Hackensack, leaves and woody stems have been found in a bed of stratified sand and clay which underlies 8 feet of sand, con- taining a few gneiss bowlders, and Overlies an old soil having an ele- vation close to sea level.5 . * “Drift Phenomena of the Palisade Ridge,” Annual Report of the State Geologist of New Jersey (1893), p. 207. * Loc. cit., p. 205, and GEORGE H. COOK, Geology of New Jersey (1868), p. 227. 3 H. RIES, Bulletin of N. Y. State Museum, Vol. III, No. 12 (1895), pp. 119, 12o. 4 Described by Dr. James Eights in 1852 as probably Mitchella repens. Pro- fessor B. K. Emerson thinks they are probably Vaccinia oxycoccus, which are the most abundant leaves in the clays of the Connecticut. See M onograph of U. S. Geo- logical Survey, Vol. XXIX, p. 718. 5 “See Drift Phenomena of the Palisade Ridge,” Annual Report of State Geolo- gist of New Jersey (1893), p. 207. .—Showing known areas of stratified drift from south of Glens Falls to north of Crown Point. FIG. I.8 LEGEND: A, moraines and kames, The numbers refer to the following places: Creek; 97, Fort Ann; 98, Mettawee River; 99, Whitehall; Too, Poultney River; Ior, South Bay; Io2, Benson Landing; Iog, Putnam Station; Io4, Addison-Rutland county line; gravel plateaus made by ice waters. generally. In some places ice-shaped drift-forms that are neither moraine or kames are thus indicated. B, ice-molded stratified drift. F, clay chiefly, but other forms of stratified drift are included. Knowledge is more certain where lines are not H, boundary lines showing approximate limits of the features inclosed. The white space next to the streams The heavier circles southeast of Io'7 and northeast of Io8 show secondary deltas. D and E, secondary deltas. C G, approximate limits reached by the standing water. broken. marks swamps, flood-plains, and low-level terraces. Round Pond, and Jenkins Mills; 89, Hopkins Pond; 94, Fort Edward; 95, Dunham’s Basin; 96, Wood 86, Glens Falls; 87, Glen Lake and Glen Brook; 88, Queensbury, Io8, Crown Point Center; 131, East Creek. Ioé, Ticonderoga; Io'7, Street Road; y Mount Defiance; IoSA, Baldwin; IO5, 456 CHARLES EMERSON PEET WESTERN PASSAGE FROM HUDSON TO CHAMPLAIN WALLEY. North of Glens Falls (where the Hudson emerges from the Adi- rondacks) the broad lowland occupied by the Hudson ends suddenly in the rather abrupt rise of the land caused by the closing in of the highlands from the east and from the west. Through this high- land there are two narrow passages—one by way of Lake George, and the other by way of Whitehall and southern Lake Champlain. These two passages are separated by highlands reaching elevations of more than 2,000 feet, and with a common elevation of I,2OO–I,8oo feet. This highland ends, however, in Mount Defiance near Fort Ticonderoga, and north of this place the two passages unite and broaden out into the wide valley between the Adirondacks on the west and the Green Mountains on the east, in the bottom of which is Lake Champlain. (See Fig. 18.) The Western or Lake George Passage is a long, steep-sided, narrow valley opening out on a clay plain near Ticonderoga at the north and connecting with the Lake Champlain valley. In the bottom of this valley is Lake George, 32 miles long, and 2 miles wide in its Southern, and one-half as wide in its northern part. Its greatest depth is IIo feet. At the south end of this valley there are two gaps, the western one of which has a rock-bottom at more than 500 feet A. T. The eastern and broader gap is blocked by a massive Com- plex gravel ridge, which is a northeastward continuation of the Glen Lake kame area. (Fig. 18, No. 87.) Well data to the south of this ridge indicate a filled valley with a bottom which is lower than the deepest known part of Lake George. Through this massive gravel ridge, which obstructs the South end of the Lake George valley and is responsible for Lake George, there is a small gap followed by a tributary of Glen Brook (the outlet of Glen Lake). This tributary appears from the map to flow through a flat-bottomed valley, and One of its branches starts from a low divide at 349 feet A. T. in this valley, which separates it from streams flowing into Lake George. As will be seen later, this flat-bottomed valley may have been the outlet for a higher glacial Lake George, which existed (if it existed at all) after the ice had retreated beyond the Glen Lake kames and before it had retreated north of Ticonderoga. (See Fig. 18, No. Ioff.) GLACIAL AND POST-GLACIAL HISTORY 457 ASTERN PASSAGE FROM HUDSON TO CHAMPLAIN VALLEY. East of the highland through which is the Lake George passage the lowland of the Hudson valley is continued to Lake Champlain with a width of 5-6% miles. The higher hilltops in this lowland are 300–400 feet below the highland farther east, and are more than double this amount below the western highland. The lower hills in the lowland have elevations of 200–400 feet lower than the higher and reach elevations of 300–520 feet. The clay and stratified drift found in the Hudson Valley is like- wise found through this lowland connecting the Hudson and Cham- plain Valleys. South of the Addison-Rutland county line and east of Lake Champlain it is somewhat discontinuous because of the numerous hills rising above the levels reached by the waters in which the clay accumulated. In the lower lands along the narrow part of Southern Champlain it probably was once Continuous. Cut into this old clay-floor there is a valley which extends from the Hudson northward. It has two divisions which will be called the Fort Edward Valley and the Whitehall-Putnam Station Valley. These will be described presently. (See Fig. 18, Nos. 94, 99, Iog.) CHAMPLAIN VALLEY. The lowland of the eastern passage above described extends into the Lake Champlain region, where it is found between the Adiron- dacks on the west and the Green Mountains on the east. It is made of the softer sedimentary rocks generally,” over which are the clays and other classes of drift Corresponding to those found in the Hudson Valley. EAST SIDE OF LAKE CHAMPLAIN. North of the Rutland county line the more hilly higher land recedes eastward from the lake shore, and from the descriptions of Baldwin" and some observations of the writer it would seem correct to state that the lower land near the lake is marked by a wide clay- mantled plain as far north as the Winooski, where gravel and sand deposits interrupt. It occurs again north of the gravel and Sand plains of the Missisquoi River. To the eastward the clay decreases in quantity or ceases altogether, and on the higher land the drift- covered or bare rock hills cease to be mantled with the clay. +American Geologist, Vol. XIII (1894), pp. 170–84. 458 CHARLES EMERSON PEET Through the clay on the plain high hills rise to levels beyond that reached by the waters in which the clay accumulated. These hills are drift-covered, and the rock outcrops frequently. Other lower hills, which sometimes have the form of ridges, have rock cores, are till-covered, and are mantled by the clay so as to subdue the original irregularities of the rock and drift. - WEST SIDE OF LAKE CHAMPILAIN. While this plain has its widest extent in the southern Champlain Valley on the east side of the lake, it has been most studied on the west side. From Ticonderoga to Port Kent the plain is not more than 3 miles wide at any point, and contracts and expands as the mountains approach or recede from the lake shore. The mountains approach close to the shore just south of Crown Point, both north and south of Port Henry, south of Whallonsburg, and north of Wills- boro. They recede from the shore, near Ticonderoga, at Crown Point, from a few miles north of Port Henry to Westport, and again from several miles south of Willsboro to a few miles north of that place. North of Port Kent the plain widens out continually to the national boundary. In its lower eastern part clay prevails at the surface, except along the streams. In the higher western part till frequently covers the surface. (See Figs. I8 and I for places mentioned.) Gravel plateaus and deltas—upper and lower series.—On approach to the higher land the plain ends abruptly against the drift-covered slopes or in gravel plateaus analogous to those in the Hudson Valley. Near the rivers the plain gives place to a series of deltas and gravel ridges, which are grouped into two series—an upper and a lower, with a space of about 120 feet between the series. The upper series has a range of about 80–IOO feet at the north and a greater range at the south. These gravel plateaus and deltas are, on the whole, higher at the north than at the south, but there are exceptions. Their ele- vations are as follows: Street Road gravel plateau, 540; delta, 320– 340. Delta on Bouquet River, 460–480; 4oo (?). North Branch Bouquet River near Tower's Forge, 460–80; 400 (?); near Reber, 440–60. Ausable River, 580–600 (?); 500. Saranac River, 640 (?); 520–40. The top of the Street Road 540-foot plateau may be higher than the level reached by the standing water. The lower series GLACIAL AND POST-GLACIAL HISTORY 459 of levels is made up of a succession of deltas and bar-like gravel ridges, and has a range from about 180 to 200 feet A. T. at the south, and 420 to 450 feet A. T. at the north, down to the level of Lake Champlain (IoI feet above sea-level). The upper series of deltas consists of two—an upper and a lower. The upper one was made by the ice waters. The lower was made by the erosion of higher gravels. The one made in the presence of the ice may be absent on some of the more northerly streams. Wave-wrought terraces.—Corresponding to these two series of gravel plateaus or deltas there are two series of wave-wrought terraces separated by an interval of about 120 feet at the south and I55 feet at the north. In this interval the terraces are either absent or very faint. Upper series of wave-wrought terraces: The upper series of ter- races have been seen at various points from Street Road to West Chazy. They have not been studied north of the latter place. This series of terraces has a range at Street Road and Crown Point of 200– 220 feet (520–320 feet A. T.), if certain rather faint terraces be accepted as wave-wrought. The range of terraces at the north varies from 75 feet near Whallonsburg (510 –435 feet A. T.) to 80 and Ioo feet farther north. On the whole the range increases north from Whallonsburg, but is greatest south, at Street Road and Crown Point. Except for the fact that the upper terrace at Whallonsburg and corre- sponding deltas on both branches of the Bouquet River are somewhat lower than at Street Road or Crown Point, the series increases in alti- tude northward. Both series of terraces are best developed and have been studied most at places from Port Kent northward. In this region the upper series of wave-wrought features is distinct, and, when one's attention has been called to it, is somewhat conspic- uous. The Series embraces wave-cut terraces and gravel beach ridges, and in favorable situations bars, spits, and hooks. At places where these features can best be seen they have a range of (I) about 80 feet at Port Kent; (2) 80–90 feet one-half mile west of Harkness Station; (3) 77 feet east of Mount Etna and a little north, between the latitude of Peru and Schuyler's Falls; (4) 60 feet northwest of Peru a few miles, and nearer Schuyler's Falls than (3) above; (5) south of the Saranac River on the farm of Thomas Riley and a neighbor, the 46o CHARLES EMERSON PEET. range is Ioo feet and possibly somewhat greater; (6) southwest of West Beekmantown one and one-half to two miles the range is 8o feet (600–68o feet A. T.); (7) three to three and a half miles north of the latter place, and about the same distance southwest of West Chazy, the range is 95 feet (605–700 feet A. T.). The lowest terrace of this series when projected southward connects with the bottom of the Fort Edward Valley. Lower Series of wave-wrought terraces: A gap intervenes between the lower terrace of the upper series and the upper terrace of the lower Series, in which the signs of wave-action are either very faint or alto- gether lacking. Because the lower series of terraces is often faint, there is some uncertainty as to the amount of this gap. At Street Road it seems to be about 120 feet; at Crown Point Too-T20, and possibly I40 feet. At Port Kent this gap is 124 feet (380–504 feet A.T.). At the Saranac River it is not known exactly. It is as much as I2O and no more than 165 feet. West of West Chazy it is 155 feet. The upper part of this lower series of terraces has been examined at a few points only; namely, west of West Chazy, where distinct terraces and beach ridges range from 450 down to 4oo or 380 feet A. T. Other lower levels not systematically studied are to be seen east of West Chazy. At Port Kent an extensive series of terraces and beach ridges and bars was observed to extend from an elevation of 380 feet well down toward present Lake Champlain level. There were at least thirteen levels represented. The terraces of the lower Series are best brought out along the streams. They have been observed on the south side of the Saranac, where sixteen levels were observed between an elevation of 300 feet and the level of Lake Cham- plain. They also occur on the Salmon River. At some of these levels, low-level deltas were built. Between Port Henry and West- port the low-level terraces may be represented at several places. At Crown Point a delta level appears to be present at 180–200 feet A. T., and indistinct terraces below this level have been seen south of Crown Point. - At Street Road distinct terraces occur at I60-180 feet, and indistinct terraces are perhaps represented up to 220 feet A. T. The upper terrace of this series projected southward falls below the Fort Edward valley. GLACIAL AND POST-GLACIAL HISTORY 461 Fossils-Below the upper terrace of the lower series of terraces marine fossils occur on the west side of Lake Champlain at the fol- lowing elevations: Plattsburg, 346 feet A. T.; Port Douglas, 3oo feet A. T.; Willsboro, 200 feet A. T.; Port Henry, 140 feet A. T. So far as the writer knows, the last-mentioned place is the most southerly point where marine fossils have actually been found. At South Plattsburg both marine shells and vegetation are found in a deposit of sand and silt, the top of which has an elevation of 220 feet. SALMON RIVER SECTION, NEAR SOUTH PLATTSBURG.” 15. Silt. I4. Ten feet of coarse gravel, with ridge topography. The sand below the gravel ridges is eroded and replaced by coarse gravel, largely of Potsdam sandstone, but some light-colored limestone. Shells in single valves. One square-shouldered valve found. . 13. Six feet of sand (and gravel?), some stratified; single valves of round-shoul- dered shells. * - 12. Fifteen to twelve feet of sand and silt with round shouldered-shells in the sand. II. Eight feet of coarse sand; shells rare—only one found. Io. Two feet of fine sand, a three-inch layer with occasional round-shouldered shells (valves together). 9. Clay and sand; a four-inch log, two inches from the bottom of the layer; shells rare. Shells and vegetation. - Two feet two inches of alternating sand and clay. Layer of vegetation one-half an inch thick, with a fragment of a beetle. One foot of sand. Two feet nine inches of sandy clay; no shells, but vegetation marks. Blue clay; square-shouldered shells in sandy Seam with specks of vegetation four feet above the river. Till; stony material, largely limestone; some purple quartzite. I. Rock. 2 The layers of sand and silt are much contorted near the surface, and again not far from the base of the section. The dip is eastward at a low angle. Just a little farther downstream there are several * DR. D. S. KELLOGG, Science, June 17, 1892, p. 341. 2 The material found in this section has not been fully identified but is being studied. Leaves in layer 6 have been identified by Professor J. M. Coulter as belonging to some species of boreal willow. The square-shouldered shells are prob- ably Saxicava rugosa and the round-shouldered shells are Tellina Groenlandica. 462 CHARLES EMERSON PEET different levels of the gravel with the form of limited terraces, which are due to the slumping down of the surface as the bank has been undercut. A layer of sand containing marine shell fragments and colored by the presence of vegetation was observed west of Mooers. It underlies Coarser gravel and sand. The exposure was not suf- ficient to allow it to be determined whether the sand with the car- bonaceous material represents an old soil or is a layer like some in the Salmon River section, colored with vegetable matter. On the east side of the lake.—Marine shells in the form of Macoma jusca and Saxicava occur at low levels. North of central Addison Township Baldwin says they are common at levels below 150 feet, and reach an elevation close to 250 feet at Vergennes. The writer was unable, however, to find any up to that level south of Otter Creek at Vergennes, and search was not made north of that place. Baldwin also reports Macoma jusca at Shelburne Falls and Morses in strati- fied sands up to 180 feet. In the northern part of Shelburne shells which from descriptions are thought to be marine are reported, he says, at 4oo feet. If this is correct, it is the highest level at which they have been found. The same writer reports shells of Saxicava and Macoma jusca in the stratified sands of the 270-foot LaMoille delta at Checkerberry village, on the south shore of Mallett’s Bay and in West Milton. Bones of a whale (Beluga Vermontana, Thompson) were reported from Charlotte Township at 150 feet above the sea." Land-snail shells have been found in high-level deposits at a number of points in the southern Champlain region a few feet beneath the surface. In one or two cases they appeared to be imbedded in the undisturbed stratified materials of wave-wrought terraces. In most cases they occur in a surface loam which has a very irregular contact with the underlying drift. A number of things connected with their occur- rence in the loam point to introduction in openings made by roots of trees, but it is possible that some were buried contemporaneously with the making of the wave-wrought terraces of the upper Series. Moraines.—Above the upper series of terraces at a number of * Vermont Geological Survey, Report in rô49, Vol. I, pp. 162–65; and DAWSON, ‘Cetacean Remains in Champlain Deposits,” American Journal of Science, Vol CXXV (1883), pp. 200–202. GLACIAL AND POST-GLACIAL HISTORY 463 points, notably (1) at Crown Point, (2) between the latitude of Hark- ness and the Salmon River, and (3) at Cadyville and westward toward Dannemorra, a moraine or a series of moraines with a peculiar ridge-like topography have been observed on the eastern mountain slope. At two places these moraines are situated across the course of streams in the valleys of which gravel plains occur on the upstream side of the morainic ridges, reaching to the level of their lowest part. The situation is such as to suggest the presence of local lakes in which the gravel was deposited. This point is men- tioned here to call attention to the fact that the ice at this stage, at any rate, and in this part of its front, did not have the same relation to the gravel plateaus as in the upper Hudson, for apparently its edge was on the landward side and the body of ice was on the lakeward side. This appears to have been true when the Street Road gravel terrace was made, but where the ice-edge and the body of ice were at Crown Point when the highest deposits of lacustrine origin were deposited is not known. It seems difficult to reconcile the stratified drift, with its eastward-dipping layers, with the position of the ice when the moraine higher up on the mountain side was made. The deltas on the Bouquet River are so situated that it is not necessary to assume either an embayment in the ice-front or a protruding tongue of ice down the Champlain Valley. The possible 580-foot Ausable “delta” may be interpreted with either front. The Saranac high-level delta indicates the presence of the ice at its northern margin, and possibly also at its western margin; but this delta, if it be a delta, is not well known. Below the level of the lowest terrace of the upper series a group of kames which may mark a position of the ice-edge was seen northwest of Peru, and morainic topography was likewise observed one and three- fourths to two miles west of West Chazy, between the upper and lower series of terraces. Eskers.--An esker with a length of eight to ten miles, and with a north-by-west and South-by-east direction, is found north of the latitude of Beekmantown," and a mile and a half northwest of Tread- well Bay. Its top has a maximum elevation of 240 feet and a com- This esker was first described by DR. D. S. KELLOGG, of Plattsburg. See Science, June 17, 1892, p. 34.I. 464 CHARLES EMERSON PEET mon elevation of 220 feet. It stands 20–40 feet above its surround- ings. The top is often quite flat and has been subjected to considera- ble wave-action. The materials are frequently coarse gravel, with occasional large bowlders. A number of wells on this esker are reported by their owners to reach clay after penetrating the gravel. Marine shells are found on the slopes of this esker a few feet beneath the surface. The streams and their valleys.--Down the slopes of the higher land the streams extended their courses as the waters of the lake, and sub- sequently the waters of the sea withdrew and exposed more and more of the lake-floor and sea-floor. The courses which the streams took were determined by the slope of the land. Into their deltas the streams have cut valleys, and some have cut, not only through the delta gravels, but also through the underlying till and into the rock below. This is notably true of the Ausable River, which has reached the Potsdam sandstone at a number of places from above Keeseville to Ausable chasm. At the latter place it has cut into the Potsdam rock to a depth of 80–100 feet, causing the falls to recede from their original position at the lower end of the chasm to their present position one and an eighth miles back. The Saranac River has not only cut through the morainic ridge west of Cadyville, but through the till and into the underlying Potsdam sandstone; again to the eastward it has cut through the upper delta deposits and underlying till into the underlying sandstone. The Saranac from Cadyville downstream some distance, and the Ausable from the lower end of the chasm to some distance above, have remarkably Crooked courses, with almost rectangular turns, which have been determined by the joint planes of the rock. (See Fig. 19.) Successive stages in the downcutting of their valley-fillings are shown by a series of river terraces on the Ausable above and below Keeseville, on the Salmon River above South Plattsburg, on the Sara- nac above Morrisonville, and doubtless on many other streams. The successive levels of the waters of the lake and of the Sea are shown on the streams by lower deltas and by lower bars and beach ridges. Some of these low-level deltas are not simple, but appear to contain glacial deposits buried in and modified by subsequent deposits. This is notably true on the Ausable. GLACIAL AND POST-GLACIAL HISTORY 465 In the southern Champlain Valley the tributaries bear evidence of recent drowning of their lower courses. North-heading streams show a recent revival, while south-heading streams show arrested develop- ment. In the eastern passage to the Hudson a valley has been mentioned which will be described in two divisions as the Fort Edward Valley FIG. 19.-Showing the relation of the joint structure in the Potsdam sandstone to one of the rectangular turns in the Saranac River. [Photograph by W. S. McGee.] and the Whitehall-Putnam Station Valley. The tributaries flowing into these valleys show characteristics similar to those of the Hudson tributaries. They descend to the main valley, over steep slopes, which have been pushed farther back on the larger streams and reduced to gentler slopes than on the smaller streams, except where the rock has been encountered. This character is to be contrasted with the comparatively gentle gradients of the streams flowing into Lake Champlain farther north, where the streams lack the sudden descent at their mouths that is characteristic of those flowing into southern Champlain or into the Fort Edward Valley, except where 466 - . CHARLES EMERSON PEET such descents have been produced by inequalities in the hardness of their beds. (See Fig. 16, A and B.) . f Fort Edward Valley–This valley extends from the south end of/ Lake Champlain at Whitehall to the Hudson River. From Dunham's Basin south it is divided into two parts. The western part ends at Fort Edward. The eastern part ends three miles farther south, and about the same distance north of Fort Miller. The narrowest part of the valley is at the edge of the highlands north of Fort Ann, where the width is one-tenth to one-fifth of a mile and the bottom is on the rock. The widest part of the valley, where the width is more than one and a half miles, is southeast of Dunham's Basin. The com- bined width of the eastern and western parts in the latitude of Fort Edward is nearly two miles. The bottom of the valley has an eleva- tion, at F ort Edward, of I40 feet, an altitude which is probably con- siderably less than twenty feet higher than the present Hudson. The same may be said,of the eastern branch of the valley three miles north of Fort Miller. At Whitehall the valley bottom is 120 feet in altitude above the sea. Between these two extremes the divide, which is near Dunham's Basin, is close to 160 feet in altitude. The valley is followed by the north-flowing Mettawee River and its tribu- tary, Wood Creek, and by the south-flowing Fort Edward Creek and Durkeetown Creek, a tributary of the Moses Kill. All these streams are very small compared with the width of the valley. The amount of cutting of the valley is difficult of exact determi- nation. At Fort Edward it certainly is less than 120 feet, and perhaps no more than 35 feet. In other places, on the whole, the indications are that there has been a cutting of less than IOO feet. The maximum possible cutting of the Hudson valley immediately to the southward is 160 feet, but may be only Ioo-12o feet. Whitehall-Putnam Station Valley.—This valley is occupied by the southernmost and narrowest portion of Southern Lake Champlain. This part of the lake, including swampy borders, has a width varying from one-tenth to seven-tenths of a mile, and a common width of one- half mile. Its sides show frequent cliffs of clay, or clay overlying silt and stratified gravel and sand, and remnants of a former valley- filling which reached, in places at least, elevations of 180–200 feet A. T. Beneath the waters of this part of the lake, and extending lA kit, cºll A M P LA IN rºllow colº's lºy to Willitºll-ll. -- --- ---------- --- |- - - - - - - - - -- - - - FIG. 20.-The submerged Poultney-Mettawee Valley, from Lake Survey Charts on which con- tour lines have been drawn. Contour interval: 5 feet, down to the ninety-foot line. 468 CHARLES EMERSON PEET beyond it to a point five miles northeast of Port Henry, is the sub- merged Poultney-Mettawee Valley. (See Fig. 20.) Submerged Poultney–Meltawee Valley.—This valley can be read from the Lake Survey charts. It occurs beneath the waters of south- ern Champlain from Whitehall to five miles northeast of Port Henry. The depth of water covering this valley varies from 12 to 55 feet Copyright by S. R. Stoddard. FIG. 21.-Photograph of southern Lake Champlain, looking north near Dresden Station. Smaller view looks northwestward from Benson Landing across Lake Cham- plain toward Putnam Station. Beneath the waters of the lake in both views is the submerged Poultney-Mettawee Valley. [Smaller photograph by W. S. McGee.] upstream from the delta. The outer edge of the latter is covered by water from 50 to 78 feet deep, depending on the interpretation of the edge. The depths of the valley are greatest at the narrowest parts, and the greatest depths are nearly as great at the south end of the val- ley as near the north end. South Bay seems to be a drowned valley partly filled, which was tributary to the main Poultney-Mettawee. The width of the valley varies from one-tenth to one-half of a mile. Its sides are often steep, and the Lake Survey charts indicate plain areas between the cliffs which rise above the water of Lake Cham- plain and the tops of submerged bluffs. (See Figs. 20 and 21.) GLACIAL AND POST-GLACIAL HISTORY 469 Erosion of tributaries flowing into southern Lake Champlain.— From South Bay northward the tributaries from the west have cut valleys 40–60 feet deep below the top of the clay, and in a few cases near the lake shore as much as 60–80 feet deep. Between the valleys the points of land show cliffs furnishing numerous exposures along the Delaware and Hudson R. R. The streams on the east side of the lake are less numerous and flow down from land with a less elevation; in general, their valleys are not so extensive. Several show erosion to a depth of 40–60 feet, and one has cut perhaps as deep as Ioo feet near its mouth. These figures refer to the depth of the valley above Lake Champlain level, and do not include depths below the lake-level. The lower parts of many of these tributary valleys are drowned for a distance of three-tenths of a mile from the cliff heads, and swampy bottoms farther up the valley in some cases occupy a probable former extension of the lake for five-tenths to seven-tenths of a mile. CHARLEs EMERSON PEET. LEWIS INSTITUTE, Chicago, Ill. [To be concluded.] GLACIAL AND POST-GLACIAL HISTORY OF THE HUDSON AND CHAMPLAIN VALLEYS. II. I. OUTLINE–Concluded. HISTORY. Hudson water body and successive positions of ice-edge as it retreated through Hudson Valley. Successive positions of the ice-edge in the passages from Hudson to Cham- plain Valley. Successive positions of ice-edge in Champlain Valley. Hudson-Champlain water body. Higher Glacial Lake Champlain. Erosion of Fort Edward Valley—making of upper series of terraces. Lake St. Lawrence. Marine Champlain. Making lower series of terraces. Extended course of Poultney-Mettawee River. Inauguration of present Lake Champlain and changes since then. Drowning of lower Poultney-Mettawee River Valley. Cutting of outlet of present Lake Champlain. History in Hudson Valley in Higher Glacial Lake Champlain time and later. Disappearance of Hudson water body. Trenching of old lake- or old sea-floor of Hudson Valley. Origin of Hudson Deeps. Drowning of lower Hudson. Post-Hudson-Champlain changes of drainage in the Hudson Valley. Piracy of Outlet Creek and beheading of Drummond Creek. Correlation of Terraces in the Champlain Valley with those in the Hudson Valley. * First assumption. Second assumption. Another interpretation. Altitude of Hudson water body. Origin of Hudson water body. Lake hypothesis. Sea hypothesis. Origin of northward rise of gravel plateaus on each hypothesis for Hud- Son water body. - - Origin of submerged channels on each hypothesis for Hudson water body. * Continued from p. 469. - 617 ÖI3 CHARLES EMERSON PEET Origin of the gaps in the moraine. Explanation of scarcity of wave-wrought features in Hudson Valley under each hypothesis for Hudson water body. Features unexplained by salt-water hypothesis of Hudson water body. Absence of distinct wave-wrought features at outer edge of Brook- lyn-Perth Amboy moraine. Presence of overwash plains at the ice-front. Absence of life certainly marine in Hudson water-body deposits. Absence apparently of tidal distribution of muds in Hudson water body. Altitude of Hudson water body. Evidence that Hudson water body was a lake. Arguments opposed to the Hudson lake hypothesis. Relation of Hudson water body to Connecticut Valley water body. Relation of Hudson water body to water body west of Palisade Ridge. Relation of Hudson water body to Lake Iroquois. Relation of Higher Glacial Lake Champlain to Lake Iroquois. Duration of Hudson water body. - Time divisions. HISTORY. HUDSON WATER BODY AND SUCCESSIVE POSITIONS OF THE ICE AS IT RETREATED THROUGH THE EIUDSON VALLEY. As THE ice retired from the Brooklyn-Perth Amboy moraine northward, it halted for a greater or less time at the successive posi- tions which are marked on the higher lands by belts of thick drift, with more or less distinct morainic topography, by elongate kame areas with the aspect of moraines, often bordered by plains of gravel and sand having the form of overwash or outwash plains, or by aggradation plains without moraine or kame areas at their source. On Staten Island possibly one morainic belt of limited extent, and on Long Island at least two and probably three such morainic belts, mark some of the halting-places of the ice, north of the main moraine. On the Triassic lowlands in New Jersey, no less than seven such positions are marked by belts of thick drift with either the moraine or kame aspect. (See Fig. 8, p. 427.) In the lower ground, both in the lowland west of the Palisade Ridge and in the Hudson Valley, the ice and the ice-waters discharged into a standing body of water. In the low ground, west of the Palisade Ridge, the deposits of the ice-waters are marked by the Complex Series of Sand- and gravel- GLACIAL AND POST-GLACIAL HISTORY 6I9 plains or plateaus, some of them heading in kames and others with ice-molded but kameless sources, which is found from the latitude of Hackensack and Englewood nearly to the northern border of the state. The deposits of the ice-waters are also marked by the clay which is found underneath the gravel and sand in the southern part of these lowlands, or spread out with little overlying sand or gravel, and which has thicknesses from Ioo feet or less, to 215 feet.* . That the water body in which these deposits accumulated may have been separated from, and perhaps was slightly higher than the Hudson water body will be shown later (p. 645). It is to be noted that the accumulations marking the successive positions of the ice- edge on the higher land are not traceable across the lowlands occupied by this water body, at least not to the same extent, either in number or continuity, as on the higher land. In the Hudson Valley the deposits marking the successive positions of the ice-edge do not have notable development south of Sing Sing, but from a little north of this place to north of Glens Falls, and beyond into the Champlain Valley, there is a succession of deposits, described above (pp. 430 ft.), which, it is believed, mark its successive positions. As the ice retreated northward, the ice-front appears to have assumed two distinct phases in different parts of the valley. Phase I.-In those parts of the valley (notably the narrower parts) where the gravel plateaus are marked either by morainic phenomena or by irregularities of similar import at the edge next to the Hudson, or by higher elevation next to the Hudson and lower next to the valley wall, and with layers dipping toward the valley wall and south- ward, it is believed that the ice protruded down the valley, and that the accumulations took place at the edge of this ice-tongue, or between * See Annual Report of the State Geologist of New Jersey for 1893, pp. I95–2 Io, and Final Report, Vol. V (1902), pp. 506–13, 595-628, 632–42. At the time this report was written three hypotheses were suggested to explain the form of these higher gravel plains and plateaus; namely, (I) that they were accumulated in a water body, either a lake or an arm of the sea; (2) that they had received their form from stagnant ice- masses; (3) that both Co-operated. In the absence of wave-wrought features, and in the absence of exposures, the junior author preferred to leave open the question of the origin of these features, where the structure was unknown, although at this time, and for some time before, it had been recognized that a water body existed in the Hudson Valley as the ice was retiring, and that both ice and water body had been influential in producing the forms there found, 62o CHARLES EMERSON PEET the ice-tongue and the valley wall. Such deposits, it is believed, are represented (1) by the terrace south of the Croton River mouth (Fig. 9, No. 20, p. 429); (2) by the moraine on the north slope of the Palisade Ridge, which has not the accompanying gravel plateau (Fig. 9, No. 15); (3) by the Jones Point gravel plateau (Fig. 9, No. 19); (4) by Roye Hook (Fig. 9, No. 29), and possibly that part of the State Camp plateau which appears to slope eastward. In some places where tributary streams head northward the ice occupied the upper portion of the tributary valley at the same time that the ice- tongue existed in the main Hudson near its mouth, so that deposits with layers dipping toward the valley wall contributed from the ice- tongue in the Hudson Valley, occur side by side with deposits from the tributary streams of ice-water which show layers dipping toward the Hudson. The main part of the State Camp plateau, which appears to have been built of materials brought by streams of ice- water down the valley of the Peekskill and its tributaries, is thought to be an example. Other phenomena which indicate the presence of the ice in the valley, against which stratified drift was accumulating at higher levels, but to which this valley ice was not active in contrib- uting, it is thought, may be represented by the deposits at Carthage Landing and Low Point (Fig. 9, No. 44), and at New Hamburg (Fig. 9, No. 46). At the latter place, however, the waters from the ice in the valley may have been active contributors in building the plateau, at least in its early stages. (5) The West Point gravel plateau, and probably the Cold Spring kames and the Cold Spring-Garrisons ter- race (Fig. 9, Nos. 31, 33) also represent deposits made at the edge of a tongue of ice which occupied the valley. Phase 2–The second phase of the ice-front is represented in the broader parts of the lower Hudson and in the broad upper Hudson where the gravel plateaus are marked by moraines or kames or undulatory topography of similar import, at the margin toward the valley walls, and by the smoother surface and steep outer face toward the Hudson, together with the dip of the layers generally away from the valley wall, and the gradation of the materials down the dip from coarse gravel into sand and finally into clay. This clay spreads out in the upper Hudson as a wide plain, rising gradually from the present Hudson River bluffs toward the gravel plateaus and the valley GLACIAL AND POST-GLACIAL HISTORY 62I walls. In these parts of the Hudson it is believed that an embay- ment in the ice-front existed in the deeper water over the lower parts of the plain, and that the ice-edge is marked (I) by the series of gravel plateaus with the characters above mentioned at their upper margin; (2) by the kames fronted by clay-plains without intervening gravel plateaus; and (3) by the series of elongate depressions like those between the plateaus of the series south of Saratoga Springs now Occupied in part by lakes, such as Round Lake and Saratoga Lake, Lonely Lake, and perhaps also Ballston Lake." Such a form of the ice-front is marked, it is believed, by the deposits (1) at Croton and Croton Landing, and at Haverstraw and North Haverstraw (Fig. 9, Nos. 22, 15, and 17); (2) at Newburg-New Windsor, and Fishkill-Dutchess Junction (Fig. 9, Nos. 37, 38, and 42, 41). Other places where the ice halted are marked (I) by the South Schodack gravel plateau (Fig. I 3, No. 73, p. 436) and the line of kames extending northwest of East Greenbush (Fig. 13, No. 74), by kames near Teller Hill, and the line extending through North Albany to Newtonville (Fig. 13, No. 65), (2) by the South Bethlehem gravel plateau (Fig. I3, No. 62); (3) by kames near New Scotland and Voorheesville (Fig. 13, Nos. 63 and 64); (4) by the Troy gravel plateau and kames (Fig. 13, No. 76); (5) by the series of kames and the gravel plateaus separated by elongate depressions at Saratoga Springs and South, where several successive positions of the ice-edge are marked; (6) by the succession of kames and gravel plateaus near Glens Falls, where several positions of the ice-edge are marked (Fig. I3, No. 85, and Fig. 18, west of No. 86, and Nos. 87 to 89, p. 454). This includes the Glen Lake kame area north of Glens Falls. The depth of water into which the ice flowed and built up kame areas and similar deposits appears in places to have been considerable, as 'much as 60 to 80, or possibly Ioo feet, if the evidence furnished by the Teller Hill kames, southeast of Albany (elevation of top, 28o feet) and the adjacent South Schodack-East Greenbush gravel plateau (elevation, 340–360 feet) be correctly interpreted. The 260–280- foot Lonely Lake gravel plateau (Fig. I 3, No. 83) was built in water 1 The writer does not mean to imply here that the plateaus between these depres- Sions were built only from successive positions marked by the depressions, for probably the building was in process during the retreat from one depression to the next succeeding 622 CHARLES EMERSON PEET which was Ioo feet deep over the plateau, if the adjacent plateaus be correctly interpreted. These figures are in accord with those showing the depth of water in which the ice succeeded in making a subdued moraine in the basin of Lake Passaic. They do not show the total depth of water in the water body, but the depth only in which the ice was able to build the moraine, kames, etc., mentioned. If the proportion of ice to débris carried were known, it would furnish a means of estimating the thickness of the ice on these moraines and kames. In the Hudson Valley no less than fifteen halting-places are thus indicated, and of these at least six are marked by distinct morainic phenomena. This does not take account of the area between Pough- keepsie and Catskill, which was observed only in transit. SUCCESSIVE POSITIONS OF THE ICE-EDGE IN THE PASSAGES FROM EIUDSON TO CHAMPILAIN VALLEY. The successive positions of the ice as it retreated from the Hudson Valley into the Lake Champlain region are not known. In the western or Lake George passage, after having built the Glen Lake- Hopkins Pond kame area (Fig. 18, Nos. 87–89), thus forming the dam that blocks the valley and makes the basin in which southern Lake George is situated, the ice is not known to have made notable deposits until the northern end of Lake George is reached, where the western passage opens out into the Lake Champlain Valley. In the eastern passage the successive positions of the ice-edge are not known. It seems probable, however, that the ice-front had a direc- tion such that local lakes were formed in tributary valleys in which clays similar to those of the Hudson and Champlain regions were deposited, but at levels higher than those reached by the Hudson water body. SUCCESSIVE POSITIONS OF ICE-EDGE IN CHAMPLAIN VALLEY. The successive positions of the ice in the Lake Champlain Valley are not well known. Some of its positions are marked by the ter- races: (1) at Baldwin and northward (Fig. 18, No. IoS, A, p. 455); (2) at Street Road (Fig. 18, No. 107) and northward; (3) by the moraine northwest of Crown Point (Fig. 18, northwest of No. 108); (4) by limited gravel areas along the mountain-side from Port Henry GLACIAL AND POST-GLACIAL HISTORY 623 to Westport; (5) by the Bouquet River high-level delta; (6) by the Reber and Towers Forge gravel plateaus or deltas on the North Branch of the Bouquet River; (7) by the moraine or series of moraines along the higher land between Harkness and Schuyler's Falls, and at Cadyville and west toward Dannemorra; (8) by the Saranac high- level gravel plateau; (9) by kames or moraine west by south of West Chazy. HUDSON-CHAMPLAIN WATER BODY. When the ice had retreated into the Champlain Valley, the Hudson water body occupied the lowland between the Hudson and the Lake Champlain Valley also, and may now be conveniently referred to as the Hudson-Champlain water body (see Fig. 22). The successive positions of the ice as it retreated up the Champlain Valley are known to the writer at a few points only, and these are on the west side of the valley. The moraines found above the highest level reached by the water body near Crown Point, and at the various places indicated in the detailed description above (pp. 462, 463), between Harkness Station and Cadyville, and west of the latter place toward Dannemorra, all indicate a general north-South and northeast-southwest direction of the ice-front, and also indicate that the ice was in the lower land and its edge was on the slopes of the higher land. This appears like- wise to have been true when the Baldwin and Street Road plateaus were built. Where the ice-edge and the body of ice were at Crown Point when the highest deposits of lacustrine origin were deposited is not known, although doubtless, it could be determined by detailed investigation. It seems difficult to reconcile the eastward dip of the stratified drift built out in the water body with the position of the body of the ice in the lowlands when the moraine higher on the mountain-side was built. The deltas, both on the main Bouquet River and on the north branch, are so situated that neither the assump- tion of an embayment in the ice-front nor a protruding tongue of ice down the Champlain Valley is necessary to explain the phenomena. The deposits of gravel at 580 feet on the Ausable may be interpreted * This name was first given to the water body occupying the Hudson and Cham- plain Valleys by MR. WARREN UPHAM, who published on this subject in 1891 in the Bulletin of the Geological Society of America, Vol. III, pp. 484–87, and in the American Journal of Science, Vol. CXLIX (1805), pp. 13 ſ. FIG. 24. FIG. 23. FIG. 22.-Approximate area once covered by the Hudson-Champlain water body on the assump- tion that it was a lake. The outline does not include the highest levels reached as the ice was retreat- ing from the Brooklyn-Perth Amboy morainc to Kill van Kull, nor does it include the extension of the area into Long Island Sound. The Newark Bay water body also is shown. FIG. 23.-Approximate area once covered by Higher Glacial Lake Champlain. No attempt is made to show the northern limit, FIC. 24.—Approximate area covered by “Marine '' Champlain. No attempt is made to show the northern limits reached by these waters. GLACIAL AND POST-GLACIAL HISTORY 625 with either form of front. The highest Saranac gravel plateau indi- cates the presence of the ice at its northern margin, and possibly some of the phenomena of the western margin indicate its presence there, but this plateau is not well known. It will be referred to again. On the whole, then, the moraines of the west side of the Cham- plain Valley, at high levels, indicate a retreat of the ice with a general north-south or northeast-southwest front, and with the body of the ice in the valley. At lower levels, in general, no embayment in the ice-front seems to be required by the gravel plateaus, although deposition of some of the stratified drift in the water body is difficult to understand if the ice occupied the lowlands, and there was no embayment. The high-level Saranac gravel plateau or delta is probably an example. It seems necessary to believe that when the moraines at high levels near Harkness and west of Cadyville were being built local lakes existed at the front of the ice in the valleys of streams now flowing into Lake Champlain, at levels higher than the level of the water body in the Champlain Valley. BIGHER GILACIAL LAKE CHAMPILAIN. As the ice retreated through the Champlain Valley, an uplift took place at the South which separated the water body in this valley from the Hudson water body south of Fort Edward and inaugurated the history of a water body which Baldwin first named Glacial Lake Cham- plain. In view of the fact that another glacial lake may be represented by the upper part of the lower series of terraces, it seems best to call it Higher Glacial Lake Champlain. This lake drained southward through the Fort Edward Valley and across the barrier south of Fort Edward. Whether the Hudson water body continued to exist for any length of time after the inauguration of Higher Glacial Lake Champlain is not known. Indeed, it is not known that its dis- appearance may not have been on the appearance of Higher Glacial Lake Champlain. By this time, or earlier, those peculiar conditions which it appears had existed through much of the history of the Hudson water body, and had prevented the making of distinct wave- wrought features, ceased to be effective, and the upper series of wave-wrought features, which may be seen from Street Road north, 626 CHARLES EMERSON PEET was made. Contemporaneously with at least the lower terraces of this upper series, the Fort Edward outlet valley was eroded. The question as to where the ice-edge was when Higher Glacial Lake Champlain was inaugurated will be referred to presently, as will also the greater range of the upper series of wave-wrought features from Street Road to north of Crown Point. When the lowest terrace. of the upper series was made, the water-level remained constant long enough for a delta to be built on a number of the northern streams. LAKE ST. LAWRENCE. After the upper series of terraces had been completed, the Fort Edward outlet was abandoned, and the water-level fell rapidly to the upper terrace of the lower series. Whether this level was the sea-level or not seems uncertain. The level of the marine fossils falls below it 70–80 feet at the north, and not far from that amount at the south, so far as the writer has been able to discover." If this water-level, represented by the upper terrace of the lower series, was not the sea-level, then it represents a lake-level made by the opening up of some outlet, presumably toward the St. Lawrence, which was lower than the Fort Edward outlet. The location of such an outlet is entirely unknown, and its existence is hypothetical. In 1895 Mr. Warren Upham suggested such a lake “occupying an area from Lake Ontario to near Quebec,” and “dating from the confluence of Lakes Iroquois and Hudson-Champlain.” Concerning it he says: From the time of union of Lakes Iroquois and Hudson-Champlain a strait at first about 150 feet deep, but later probably diminishing on account of the rise of the land about 50 feet, joined the broad expanse of water in the Ontario basin with the larger expanse in the St. Lawrence and Ottawa valleys and the basin of Lake Champlain. At the subsequent time of ingress of the sea past Quebec the level of Lake St. Lawrence fell probably 50 feet or less to the ocean level. The place of the glacial lake so far west as the Thousand Islands was then taken by the sea.” As thus defined, Lake St. Lawrence would fall in with the non- fossiliferous part of the lower series of terraces in the Champlain region. It is to be noted, however, that these terraces do not belong * If fossils occur up to 250 feet, South of Vergennes, as reported by early investi- gators, the above may not hold. 2 American Journal of Science, Vol. CXLIX (1895), page 16. GLACIAL AND POST-GLACIAL HISTORY 627 to the Hudson-Champlain water body, nor even to the Higher Glacial Lake Champlain water body, but were made after the abandonment of the Fort Edward outlet. In 1903 Mr. Upham referred the low- level delta of the Hudson at Fort Edward and certain high-level terraces in Chesterfield in the Champlain region to Lake St. Lawrence. As will be seen from the foregoing account of the history of this region, the present writer considers this low-level delta at Fort Edward as having been made either in the latest stage of the Hudson-Cham- plain water body or in the earliest stage of Higher Glacial Lake Champlain, and the high-level terraces in the northern part of the Champlain region as having been made in Higher Glacial Lake Champlain. If the non-fossiliferous levels in the lower series of terraces in the Lake Champlain region be referred to Lake St. Law- rence, the Fort Edward delta and the high-level terraces in the northern Lake Champlain region cannot be so referred. Since it is doubtful if the water body in which either the high-level terraces. or the Fort Edward delta were made reached to the St. Lawrence, it would seem to be inappropriate to call it Lake St. Lawrence. Altogether it seems best either to reserve this name for the hypo- thetical lake which followed the union of the water bodies in the Ontario and Lake Champlain regions, as originally defined by Upham, or to use it, or some other name, for the water body succeeding Higher Glacial Lake Champlain and draining (presumably) toward the St. Lawrence after the abandonment of the Fort Edward outlet. MARINE CHAMPLAIN. If the upper terrace of the lower series represents the sea-level, then, on the abandonment of the Fort Edward outlet, the history of the Higher Glacial Lake Champlain was closed, and that of Marine Champlain was inaugurated when the water had fallen to the level of this terrace. If during the fall of Higher Glacial Lake Champlain level to the upper terrace of the lower series there was no change in the altitude of the land, then, since the difference in level between the two series is generally 120 feet, Higher Glacial Lake Champlain must have been at its closing stage 120 feet above sea-level, and at its higher stage, barring uplift during its history, it must have been at least 75–Ioo feet higher. If the upper terrace of the lower series 628 CHARLES EMERSON PEET of terraces does not represent the sea-level, but does represent a lake-level, then Higher Glacial Lake Champlain was more than I2O feet A. T. when its outlet was abandoned. It is to be noted that the level of the Fort Edward outlet valley at Whitehall is close to 120 feet A. T., and if Higher Glacial Lake Champlain at the close of its history was 120 feet above sea-level, then there has been no change in level in this part of the outlet since that time, but farther south, at the I60-foot divide near Fort Edward, there has been an uplift of more than 40 feet. - During Marine Champlain time the lower series of terraces was made in the Champlain region from the uppermost marine level down to near the present Lake Champlain levels. Since the upper- most terrace of the lower series, when projected southward, falls below the Fort Edward outlet level, and since marine fossils have not been found south of Port Henry, where they were found at a level of 140 feet and lower, it is clear that the sea did not reach south as far as the Hudson Valley." It has been calculated, by projecting the terrace gradient Southward, that Benson Landing or Putnam Station was approximately the southern limit reached by the waters forming the upper terrace of the lower series. During the time in which the lower series of terraces was being made, which it will be convenient to refer to as “Marine” Champlain” time, uplift was taking place, greater at the north than at the South, thus producing a wider range of the lower series of terraces at the north than at the south. EXTENDED COURSE OF POULTNEY-METTAWEE RIVER, While the waters of the south end of “Marine” Champlain were receding northward on account of the uplift of the land, or at first on account of the cutting of the outlet of Lake St. Lawrence, if “Marine” Champlain includes lake terraces, and later on account of the uplift of the land, the streams which had flowed into Higher Glacial Lake Champlain, and which, because of the rapid fall of its water-level, had 1 Since the Fort Edward Valley was an outlet valley during Higher Glacial Lake Champlain time, this is of course necessarily true, unless there was a great depression of the land between Higher Glacial Lake Champlain time and Marine Champlain time. There are no indications whatever of such a de Bººk, l - ºłº 4 yº. g; Weis - “Marine” Champlain levels would thus include both these of the hypothetical Lake St. Lawrence and the levels marked by marine fossils, which are called Marine Champlain levels (without the quotation marks). GLACIAL AND POST-GLACIAL HISTORY - 629 extended their courses across the old lake-floor plain to the new shore, finally were extending their courses across the old sea-floor to the reced- ing shore. This was true of the Poultney and Mettawee Rivers, which during Hudson-Champlain and Higher Glacial Lake Champlain time debouched into that water body by independent mouths (see Fig. 25, A). On the fall of Higher Glacial Lake Champlain to “Marine” Champlain they became united and with other formerly independent streams extended their courses across the newly exposed lake-floor from near Whitehall to the new water-level, which was, perhaps, G FIG. 25.—Changes in the Poultney-Mettawee River System. A, the system dissevered in Hudson-Champlain time; B, the united and extended courses of the Poultney and Mettawee Rivers and their tributaries at the beginning of “Marine’’ Champlain time; C, the same at the close of “Marine '' Champlain time or on the inauguration of present Lake Champlain; D, the Poultney-Mettawee system dissevered by the tipping of the water of Lake Champlain into the southern end of its basin caused by differential northern uplift; E, Port Henry; F, Benson Landing and Putnam Station; G, Poultney River; H, Mettawee River. - somewhere near Putnam Station. The main stream of these united streams is referred to as the Poultney-Mettawee River (see Fig. 25, B). As the “marine” water body gradually withdrew, this stream extended its course to the new levels, and finally at the close of Marine Champlain time, on the inauguration of present Lake Champlain, it had its mouth some five miles northeast of Port Henry (Fig. 25, C, E) where, apparently, it built out a delta which is now about 23–51 feet above sea-level or 50–78 feet below lake-level (Fig. 20, p. 467). During “Marine” Champlain time this stream cut out the channel in the clay plain described above (pp. 466–68) from Whitehall to Benson Landing and northward to beyond Port Henry. Deposits made by the stream at successive positions of its advancing terminus, 63o CHARLES EMERSON PEET other than the submerged delta, have not been recognized, but they are in part beneath the waters of the lake. The earlier deposits, however, should be found at low levels north of Benson Landing. INAUGURATION OF PRESENT LAKE CHAMPLAIN AND CHANGES SINCE THEN. The emergence from the sea of the barrier which makes present Lake Champlain, closed Marine Champlain history and inaugurated present Lake Champlain. By greater northern uplift Lake Champlain has been warped into the Southern part of its basin, thus submerging the lower Poultney-Mettawee Valley, dissevering its system, and drowning the lower courses of its tributaries, including the South Bay Creek, and numerous other streams in southern Champlain (see Fig. 25, D, Fig. 20, and Fig. 21). - The streams in northern Champlain did not have their courses extended because of the uplift, for the outlet at the north controlled the water-level. Their courses have been extended only by the lowering of the water-level because of the cutting down of the outlet—an amount which Baldwin" has placed at 50 feet, but con- cerning which the writer has made no observations. Terraces lower than those of Marine Champlain have been made in present Lake Champlain and exposed to view by the lowering of the water-level due to the cutting of the outlet. With this uplift, greater at the north than at the south, came the revival of north-heading streams and the arrest in the development of South-heading streams—a process which seems, from the topo- graphic maps, to be well shown by East Creek, and by Dead Creek and its south-heading tributaries. Revival seems to be shown by the north-heading tributaries of Dead Creek. The rapid down-cutting of the Poultney-Mettawee River, because of its steep northward gradient (I2O feet in 14 miles, if the estimates of elevations at the beginning of Marine Champlain time be correct) surpassed that of most of its tributaries, which had neither the advan- tage of its steep northward gradient (since most of them had either an eastward or westward flow), nor had they the advantage of the volume of water of the larger stream. Consequently these tributaries American Geologist, Vol. XIII (1894), p. 104. GLACIAL AND POST-GLACIAL HISTORY 631 were left to descend over steep slopes into the valley of the main stream (See Fig. I6, A, p. 452). The larger tributaries have been able to push this steep part of their gradient farther back from the main stream than the Smaller ones. South-heading tributaries, with the advantage of the steep gradient given by the attitude of the land when the Poultney-Mettawee was cutting its channel, were more successful in keeping pace with the cutting of their mains, but since the northern uplift they have been arrested in the continuance of this work, while north-heading tributaries have been given the advantage. It is believed that on some of the streams this record can be read from the topographic maps. HISTORY IN HUDSON VALLEY IN HIGHER GLACIAL LAKE CHAMPLAIN TIME AND LATER. The history of the Hudson Valley has been left at the point where the wave of uplift brought a barrier south of Fort Edward into effective position and inaugurated Higher Glacial Lake Champlain (see Fig. 23). How long the Hudson water body survived is not known. It is not known, indeed, that its history overlaps to any extent the history of Higher Glacial Lake Champlain. The uplift which produced the latter may have been the final cause for the disappearance of the former. If the Hudson water body survived long after the inauguration of Higher Glacial Lake Champlain, then deposits made by the outlet stream from that lake would be expected at the point where it debouched into the Hudson water body. They may be present, but the region where they would be expected has not been studied enough to determine this point. Some stages in the lowering of the Hudson water body are represented by the low-level deltas mentioned at South Bethlehem, on the Hoosick River, on the Batten Kill, on the Hudson River, and possibly on other streams. It is a question whether any of these fall within Higher Glacial Lake Champlain time. Possibly the 280–300-foot Hudson River delta does, but if so it was made in Higher Glacial Lake Champlain and not in the Hudson water body. If the Oniskethau low-level delta at South Bethlehem falls within that time, the Hudson water body had been reduced to a very shallow representative of its former extent, for this delta is only 20–40 feet higher than the lowest part of the floor opposite this place. 632 - CHARLES EMERSON PEET Whatever may have been the history soon after the inauguration of Higher Glacial Lake Champlain, it is certain that long before the close of that history the Hudson water body had disappeared, and that the outlet stream of Higher Glacial Lake Champlain, the greater part of which flowed through the present Hudson River valley (see Fig. 23), had taken its course across the old floor of the Hud- son water body, that the streams which had debouched into the Hudson water body had extended their courses across its old floor to the main stream flowing through the bottom of the trough made by the meeting of the slopes of the old floor. Into this old floor the outlet stream of Higher Glacial Lake Champlain trenched its course at a rate so rapid that the tributary streams were unable to keep pace with it, and they were thus made to descend to their main over steep slopes, which the Small streams have not yet succeeded in pushing back far from the present Hudson bluffs (see Fig. 16, A). Where the mouth of the Hudson was at this time is a subject for discussion, but it is certain that the land was higher than now and that the Hudson, at least in those regions where it is bordered by clay plain, cut its channel to depths now covered by the waters of the Hudson estuary Io-50 feet deep north of Catskill. Just how deep the cutting of this channel in the lower Hudson was during Higher Glacial Lake Champlain time is a matter of less certainty for two reasons: First, because there has been subsequent filling, as shown by at least 25 feet of clay at Croton, which contains “flags” and shells, while the clay below does not contain them, as reported by the dredgers excavating clay from the river for brick-making; second, because of the occurrence of certain “deeps,” the origin of which is a matter of discussion. Such deeps are the New Hamburg “deep” (120 feet), the West Point deep (216 feet), Stony Point- Verplanck’s Point deep (Io2 feet), Fort Washington deep (155 feet), and others. These deeps may be due either to scouring" by the Hud- son during Higher Glacial Lake Champlain time or by the tide since then, or they were original depressions bridged by buried masses of stagnant ice over which the large amount of clay eroded from the upper Hudson during Higher Glacial Lake Champlain time was * For ability of a stream to scour its channel below sea-level see CHAMBERLIN AND SALISBURY'S Geology, Vol. I, pp. 162 and 184. GLACIAL AND POST-GLACIAL HISTORY 633 carried to the sea. If such ice-bridges existed, the deposition in these “deeps” of materials carried by the waters of the stream would not be possible, and the melting of the ice after the clay from the upper Hudson had been carried across these ice-bridges would leave the “deeps.” - While the origin of these deeps is open to discussion, on the whole it seems certain that the Hudson had cut its channel to a considerable depth below present sea-level before the close of Higher Glacial Lake Champlain time. This necessitates an altitude of the land at that time higher by the amount of the general cutting, at least. In the process of down-cutting the river terraces which occur in the upper Hudson and on the tributary streams in both upper and lower Hudson, were made. Some river terraces had also been made in the tributary valleys before the close of the history of the Hudson water body. Before the close of Higher Glacial Lake Champlain history, it is believed, the depression which has drowned the lower Hudson and its tributaries had begun. One basis of this belief is the amount of filling of the southern Hudson since the submergence. While this is a matter subject to revision on more accurate knowledge, calcula- tions made indicate that the contributions of the Hudson and its tributaries since the submergence would be inadequate to furnish the material for this filling, and therefore that some of it was supplied by the cutting of the trench in the old lake-floor or old sea-floor in the northern Hudson Valley, before the Fort Edward outlet was abandoned. Post-HUDSON-CHAMPLAIN CHANGES OF DRAINAGE IN THE HUDSON VALI.E.Y. By the close of Higher Glacial Lake Champlain history nearly all the cutting by the Hudson south of Fort Edward had been accom- plished. This is shown by the fact that the Fort Edward outlet floor is within less than 20 feet of the present Hudson level. Aside from the trenching of the consequent courses of the streams below the floor of the Hudson water body, the pushing back of the steep gradients from the neighborhood of the Hudson River bluffs, and the development of subsequent tributaries on the consequent 634 CHARLES EMERSON PEET streams, a part of which at least was accomplished in Higher Glacial Lake Champlain time, there have been few changes in the valleys of the small streams since the disappearance of the Hudson water body. Depression of the land, part of which probably took place before the close of Higher Glacial Lake Champlain time, has drowned the lower courses of many tributaries from Troy south, and gravel has been carried out from the higher land into the trenches in the clay, making, in Some cases, a gravel-floor, and in others, by further erosion, a gravel- floor and gravel-capped clay terraces, as on the Oniskethau. In a few places it seems likely that readjustments in drainage have taken place because of the competition of neighboring streams. This seems to be true of the relations between Drummond Creek, a tributary of Saratoga Lake, and Outlet Creek, the outlet of Ballston Lake, which flows into Round Lake from the northwest (see Fig. 26). Piracy of Outlet Creek and beheading of Drummond Creek.-- Drummond Creek flows northeastward into Saratoga Lake through a rather broad, flat-bottomed val- ley, which is the northeast- ern part of one of the de- pressions between gravel plateaus South of Saratoga. Although this depression extends southwest beyond Ballston Lake, its south- FIG. 26.-Piracy of Outlet Creek. - - o, c-outla cº, D. c-Drummond creek "*P* including Ball- B. L=Ballston Lake; R. L.-Round Lake; S. L.- ston Lake, is not drained Saratoga Lake. through Drummond Creek, but by a stream called Outlet Creek, flowing from Ballston Lake northeastward to a point a little over a mile from the lake near a place named East Line, where it makes a sharp turn southeast- ward and descends through a narrow, steep-sided valley with a high gradient to Round Lake (188 feet in altitude). At the point where Outlet Creek makes its southeastward turn its floor is something less than 280 feet in altitude. The question whether Drummond Creek has been beheaded by the working back of Outlet GLACIAL AND POST-GLACIAL HISTORY 635 Creek, which tapped it and thus diverted its waters into Round Lake, would seem to rest upon the question whether Ballston Lake, which is now 285 feet above the sea, was ever enough higher to drain over the divide at 3oo feet, down Drummond Creek into Saratoga Lake. CORRELATION OF TERRACES IN THE CHAMPLAIN VALLEY WITH THOSE IN THE HUDSON VALLEY. In the description of the wave-wrought terraces of the Lake Champlain region mention was made of the fact that in the upper series of terraces there is a range from the highest to the lowest of about 200–220 feet at Street Road and Crown Point. This great range may extend north of the latter point, but it is not known so far north as the Bouquet River. From this river north the known range is from 75 to IOO feet, apparently increasing from South to north. The question arises at once: What is the explanation of the greater range of wave-wrought features at Street Road and Crown Point? Were they produced wholly in Higher Glacial Lake Champlain, or are part of them due to wave-action in the preceding Hudson- Champlain water body before the inauguration of Higher Glacial Lake Champlain 2 The decision of these questions depends on the correlation of the terraces in the Champlain Valley and of these levels with those in the Hudson Valley. Since terraces have not been found in the narrow east and west passages which would connect the levels in the Hudson and Champlain regions, the possible correla- tion of the terraces in these regions must be covered by a “series of assumptions which shall include the range of probable fact.” First assumption.—If the making of the gravel plateaus at Street Road and Crown Point be correlated with the emergence of the barrier at the south of the Fort Edward outlet, then the wave-wrought terraces of the upper series all fall within the history of Higher Glacial Lake Champlain and the greater range here might be due to the Cutting down of the outlet and consequent fall of water-level, before the ice had retired far enough north to permit the making of all these terraces in the northern Champlain valley. If this be the true explanation, it would require a total cutting of the Fort Edward outlet of 200–220 feet, during Higher Glacial Lake Champlain history, which is greater by 60–80 feet than any possible barrier 636 - CHARLES EMERSON PEET indicated by the present topography. The second hypothesis to account for the greater range of wave-wrought terraces in Southern Champlain, on the assumption that they were all made in the Higher Glacial Lake Champlain water body, is that during the history of this water body there were not only the conditions mentioned in hypothesis I, but there was also a warping upward of this particular portion of the basin, in excess of the up-warping at the outlet, so as to produce the extra spread of terraces. On the most favorable assumption as to the original height of the barrier south of Fort Edward, this would require no less than 60–80 feet of up-warping at Street Road and Crown Point in excess of that at the outlet." The emergence of the barrier assumed in this correlation requires a fall of the Hudson-Champlain water-level of 120 to 160 feet,” while the ice was retiring from the neighborhood of the barrier south of Fort Edward to Street Road and Crown Point. If the Hudson- Champlain water body was an arm of the sea, this fall of water-level was due to uplift. The time necessary to produce this uplift was sufficient to permit the making of at least one secondary delta near Glens Falls on the Hudson—the 340-foot delta, and perhaps a sec- ond—the 280–300-foot delta east of the latter (see Fig. 18, p. 455). It is possible, however, that the 280–300-foot delta was made in the Higher Glacial Lake Champlain water body. It is a question whether this length of time was not more than that required for the ice * A third possible explanation of the extra spread of the terraces in this part of the Lake Champlain basin is that some of these terraces were not made in Higher Glacial Lake Champlain time, but were made in the interval between that time and Marine Champlain time. The lower part of the upper series of terraces at Street Road and Crown Point would thus be correlated with the fainter terraces which have been seen at a few places in the gap between the upper and lower series. This hypothe- sis had been considered, but was not included in the original article in the Journal of Geology because of several objections to it. The discovery by J. B. Woodworth of several terraces on the Mooers quadrangle in a position corresponding to the writer's interval between the upper and lower series of terraces has removed one of these objections. (See 56th Annual Report of the N. Y. State Museum, 1904, p. r. 9.) * A fall of more than this is required if the doubtful 460-foot plateau north of Glens Falls marks a water-level. This plateau was not thought by the writer, while in the field, to be a standing water form, but there are some reasons for entertaining the idea that the standing water at one time reached this level. These reasons are involved in the explanation of the present gradient of the Hudson in harmony with the history stated in this article, but are not indispensable to this explanation. GLACIAL AND POST-GLACIAL HISTORY 637 to retreat to Street Road and Crown Point, and to make any deposits that are known between the deposits in the vicinity of Glens Falls and these points. If the time for the ice to retreat from its positions near Glens Falls to Street Road is indicated by the time necessary to make the two secondary deltas of the Hudson River, it would seem that the ice retreat was excessively slow. If, on the other hand, the rate of retreat was similar to that in the lower Hudson, it would seem that the rate of uplift was excessive. There are, however, some indi- cations that the history between the making of the glacial deposits in the vicinity of Glens Falls and those at Street Road and Crown Point was somewhat complicated, and, if so, there may have been time for the uplift mentioned during this history. If the Hudson-Champlain water body was a lake, the fall of the water-level which preceded the emergence of the barrier south of Fort Edward was in part due to the cutting of the Brooklyn Narrows outlet. The full, amount of the cutting of this outlet, so far as known, is abºº f this be distributed among the sixteen or more halting places between Brook- lyn and Street Road, it would produce but a few feet of fall during the time of the retreat of the ice from the barrier South of Fort Edward to Street Road and Crown Point. Even if allowance be made for the increase in rate of cutting of the Narrows outlet on the accession of the waters of Lake Iroquois through the Rome outlet, the lowering of the water-level from this cause, while the ice was retreating from the barrier South of Fort Edward to Street Road, can have been only a small part of the total change in water-level produced by the cutting of the Narrows outlet. It would therefore follow that a large part of the 120–160-foot fall of water-level (or more) required in order to permit the emergence of the barrier south of Fort Edward was due to uplift, and the above remarks concerning the rate of the uplift and of the ice retreat would apply. The correlation above assumed has the advantage of being in accord with the facts which suggest the existence of a Higher Glacial Lake George during the retreat of the ice from north of Glens Falls to near Street Road, and the disadvantage of permitting the forma- tion of wave-wrought terraces at Street Road and Crown Point in Higher Glacial Lake Champlain in the approximate neighborhood of the ice under conditions which are cited below as causes preventing 638 CHARLES EMERSON PEET the formation of such terraces in the Hudson-Champlain water body. - Second assumption.—If the upper levels at Street Road and Crown Point be correlated with levels above the barrier south of Fort Edward, then the Street Road gravel plateau, the Crown Point high-level deposits, and a part of the upper series of wave-wrought terraces at these places were formed in the Hudson-Champlain water body. The absence in northern Champlain of the upper levels in the upper series of these wave-wrought terraces may be ascribed to the presence of ice here while they were being formed in southern Champlain. Under this assumption the demands made by the post- Higher Glacial Lake Champlain uplift at Street Road and Crown Point, will possibly permit the correlation (I) of the highest Street Road terrace with the 389-foot Glens Falls level, and (2) certainly with the 340-foot level. If the first correlation be correct, it is fatal to the hypothetical Higher Glacial Lake George; or if the Higher Glacial Lake George be real and not hypothetical, then its existence is fatal to the first correlation, and probably also to the correlation of the 340- foot Glens Falls delta with the Street Road and Crown Point levels, although it is barely possible that the latter correlation is permissible, even though the Higher Glacial Lake George did exist. If some ter- races of the upper series at Street Road and Crown Point be thus assigned to the action of the Hudson-Champlain waters, then it fol- lows that when Higher Glacial Lake Champlain was inaugurated the ice was as far south as the delta of the Bouquet River, where the known range of the upper series of terraces is not greater than may be assigned to the latter lake. But if the ice was present on the Bouquet River when Higher Glacial Lake Champlain was inaug- urated, there was time for the cutting down of the outlet as it retreated northward, and thus it would be expected that the terraces at the Bouquet River would have a greater range than northward where the uppermost wave-wrought terrace was not made until after the uppermost Bouquet terrace was completed. If the doubtful 400-foot delta on the north branch of the Bouquet River represents a water- level, then the range is greater than farther north, as would be expected if the water-level fell as the ice retreated. If, however, this level be rejected and the 435-foot level be the lowest, the terraces have GLA CIAL AND POST-GLACIAL HISTORY 639 a less range than farther north. This might be due to an approxi- mately stationary water-level as the ice retreated from the Bouquet River and a later differential northern uplift. The water-level may have been maintained (a) because the outlet was cut but little at this time. This small amount of cutting of the outlet may have been because of a slow rate of cutting or it may have been because of a short period of time between the exposure of the shore to the action of the waves in the latitude of the Bouquet River and in more northerly latitudes. The general north-south trend of the ice-edge, more or less parallel to the shore where the trend is known, would favor the opening up of a large part of the shore to the action of the waves by a small amount of recession of the ice-edge from it, and might thus give but a short time for the water-level to fall as the ice retreated north from the Bouquet River to north of the Saranac. (b) It is possible that uplift of the outlet maintained the water-level, or even caused it to rise in the northern part of the basin as the ice retreated, in spite of the cutting of the outlet. When the ice had retired beyond the Saranac River some distance and the water-level began to fall throughout the basin, differential northern uplift would produce a greater range of terraces at the north than in the latitude of the Bouquet River. - If the water-level remained approximately stationary for some time as the ice was retreating, more pronounced shore features would be expected to mark this level. The writer has not observed any such difference in the development of these features as the hypothesis would require. The difficulties avoided by accepting the uncertain levels which make the range of terraces of the upper series here greater than farther north, and yet less than farther south inclines the writer to this interpretation. Another interpretation.—The above has been written on the assumption that either the 580-foot Ausable, or the 640-foot Saranac gravel plateau, or both of them, are deltas made in the presence of the ice, and that the 500-foot Ausable and 520–540-foot Saranac deltas are the later product of erosion of the higher gravels. If it should be found that neither the 580-foot Ausable nor the 640-foot Saranac deposits are glacial deltas, but that the 500-foot Ausable and the 520–540-foot Saranac deltas are the highest, and if also some of the 64o CHARLES EMERSON PEET more indistinct and uncertain terraces at Street Road and Crown . Point be assumed not to be wave-wrought, then, because the wave- wrought terrace curve and the delta curve would be made to cross in the southern Champlain region, another succession of events must be assumed: After the ice had retired beyond the Saranac River, and after the 500-foot Ausable and the 520–540-foot Saranac deltas had been made in the Hudson-Champlain water body, the uplift at the south took place which inaugurated Higher Glacial Lake Champlain, and further uplift took place which tipped this water body into the northern end of the basin, causing it to rise to the level of the highest terrace in the upper series. The cutting of the outlet then permitted the upper series of terraces to be made. e; On the whole it seems best to accept the reality of the upper terraces at Street Road and Crown Point, and to interpret these levels as in part Hudson-Champlain levels, and the lower part of this upper terrace series in the vicinity of Street Road and Crown Point and the entire upper series of terraces from the Bouquet River to north of the Saranac, as due to the waters of Higher Glacial Lake Champlain. While this may now seem to be the best interpreta- tion, it certainly is not demonstrated. ALTITUDE OF THE HUDSON WATER BODY. If the Hudson water body was a lake, its height above sea-level is indicated by three things: (1) elevation of the southern barrier at that time; (2) height above sea-level of Lake Iroquois, which drained into this Hudson water body through the Rome outlet; (3) the amount of change in elevation of the barrier since it emerged from the Hudson water body, and produced Higher Glacial Lake Champlain. Elevation above sea-level of the southern barrier.—If the sub- merged extra-morainic Hudson channel was used at this time, as a part of the outlet valley, and if the Narrows channel was cut entirely as an outlet channel, then the land must have been higher than now by 122 feet plus the amount of the slope of the channel to the sea. With the large volume of water flowing through this valley, it may have been cut to a very gentle gradient, and the elevation of the Hudson water body above the sea-level may not have been more than 35–50 feet. It may have been much more. GLACIAL AND POST-GLACIAL HISTORY 64I Evidence from the altitude of Lake Iroquois-Since this lake drained into the Hudson water body, it follows that the Hudson water body was lower than Lake Iroquois. The level of the latter has been calculated at about 200 feet." It follows then that the Hudson water body was less than 200 feet above sea-level, by the amount of fall of the outlet stream from Lake Iroquois to the Hudson water body. If the lower delta of the Mohawk mentioned by Professor A. P. Brigham” at Schenectady (34o feet A. T.) was deposited by the Mohawk and not by streams of ice-water from the ice-front, it would require an average slope of this outlet stream of less than 2% feet per - mile to permit the Hudson water body to be above sea-level. Amount of uplift of barrier south of Fort Edward since inaugura- tion of Higher Glacial Lake Champlain.—Since the barrier is now no more than 26o and no less than 220 feet A. T. it follows either that the Hudson water body was above sea-level when the barrier emerged from it, or, if it was at sea-level, there has been an uplift of 220–260 feet since the inauguration of Higher Glacial Lake Cham- plain. Since changes in the gradient of the outlet valley may require an uplift of 60 feet or so, since the close of Higher Glacial Lake Champlain history,” it leaves an uplift of 160–200 feet to take place during the history of this lake. If there was this amount of uplift during this time, then the Hudson water body was at sea-level when the barrier which produced Higher Glacial Lake Champlain emerged from its waters. ORIGIN OF HUDSON WATER BODY.4 There are two hypotheses to explain this water body. 1. (a) The water body was a lake made by a barrier at the south. * Monograph 41, U. S. Geological Survey, p. 775. 2 Bulletin of the Geological Society of America, Vol. IX (1898), p. 205. 3 This is based on the assumption that the valley at Whitehall has not changed in level and was 120 feet above sea-level when Higher Glacial Lake Champlain fell 120 feet to “Marine” Champlain level, and on a reasonable assumption as to the slope of this outlet valley. It is to be remembered, however, that the Fort Edward outlet valley may have been more than 120 feet A. T. at the close of the Higher Glacial Lake Champlain, and if so the 60 feet should not be subtracted from the present altitude of the barrier to obtain the amount of uplift during the history of the lake. It is possible indeed that something should be added to allow for recent depression. 4 See WARREN UPHAM, American Journal of Science, Vol. CXLIX (1895), pp. 13 ff.; R. D. SALISBURY, Glacial Geology of New Jersey (1902), pp. 195 ft., 51 1, 512, 642. - - CHARLES EMERSON PEET (b) There was a succession of lakes made by a succession of barriers, or by a migrating barrier. - 2. The water body was an arm of the sea. Aside from the deposits made in its waters there are four series of phenomena that must be accounted for in any explanation of the Hudson water body. They are: (1) the rise in level of the deltas and gravel plateaus northward; (2) the submerged channels, both in the lower Hudson and in the upper Hudson as far north as Troy; (3) the gap in the moraine at the Brooklyn Narrows, and the gap in the moraine at Perth Amboy, occupied by Arthur Kill (see Fig. 8, p. 426); (4) the scarcity of wave-wrought features. 1. The rise of the gravel plateaus northward.—Under either of the above hypotheses the land was relatively lower at the north during the presence of the water body than it is now, and there has been subsequent greater northern uplift. This greater northern uplift is necessary to account for the disappearance of the Hudson water body, if it was a lake, because the depth of the floor below the delta levels exceeds the known amount of the cutting of the outlet. If the Hudson water body was a lake, the amount of northern uplift necessary to produce the present altitude of the deltas is greater than the amount necessary if they were formed in the sea, for the following reason: As the ice was retreating, the outlet was being lowered, so that the more northerly deltas must have been made at successively lower levels, unless there was some action to maintain the water-level. If the amount of cutting of the outlet be distributed among the sixteen or more different stands of the ice south of Street Road, it would cause but a small amount of fall between the successive stands. Even if the effect of the accession of the waters from Lake Iroquois by way of the Rome outlet be taken into consideration, and reasonable allowance be made for the increase in rate of cutting after that, it makes the fall in water-level between successive positions of the ice a comparatively small amount, much less than could be read from the topographic maps. Inequality in level of deltas due to this cause is much less than that due to unequal building up at 618; J. B. WooDworth, 55th Annual Report N. Y. State Museum (1903), p. r. 9 f. The writer had not seen this report at the time this article was published in the Journal of Geology. GLACIAL AND POST-GLACIAL HISTORY 643 the successive positions of the ice. In the aggregate, however, the amount of fall of water-level is considerable. If the cutting of the outlet during the history of the Hudson water body was 122 feet, it requires, in order to produce the present delta gradient, that the last delta made in this water body undergo an uplift of 122 feet more than would be required if they were all built in the sea at one stand of the land. e 2. Origin of the submerged channels.-Under the first hypothesis (the lake hypothesis) the land was not only relatively lower, at the north than now, but at the south, from the beginning of the ice- retreat or soon after, it was higher than now. Its final altitude, however, before the recent submergence may not have been its alti- tude when the ice began its retreat. If the land at the south had its full altitude when the retreat of the ice began, then depression only is necessary here since then. If the full altitude was attained only after the ice had retreated some distance, the movement at the south was first one of uplift and finally one of depression. During the higher altitude, the channels, which are now under the waters of the Hudson estuary, were eroded and subsequent depression of the land has submerged them. Under the estuary or salt-water hypothesis the land was lower than now both north and South, when the gravel plateaus and other standing-water features were produced, and was subsequently uplifted; erosion produced the channels, and subse- quent depression submerged them. Under either hypothesis, then, the retreat of the ice was followed by a time of higher altitude of land than now, and was succeeded by one of depression. The chief differ- ence in the hypotheses is in the original altitude of the land and the time of uplift. According to the salt-water or estuarine hypothesis, the time of uplift was on the inauguration of Higher Glacial Lake Champlain, although the uplift may have been in progress in the southern Hudson before the emergence of the barrier in the northern Hudson that produced Higher Glacial Lake Champlain. The amount of this uplift before the disappearance of the Hudson water body is limited, however, by the levels which would give the sea access to the northern Hudson, if the water body was an arm of the sea. According to the lake hypothesis, the land was higher than now when the ice began its retreat, or soon after, and had either attained 644 CHARLES EMERSON PEET its full height then or did so during the retreat of the ice. According to either hypothesis, the full altitude of the southern Hudson had been attained before the close of Higher Glacial Lake Champlain history, and probably southern depression had begun. 3. The gaps in the moraine.—There are two gaps in the moraine between Brooklyn and Perth Amboy, the Narrows gap and the Arthur Kill gap (p. 426). The gap occupied by Arthur Kill has slopes which indicate that it may have been cut down from an elevation of from 25 to 40 feet above tide. The Narrows gap has steep slopes, which indicate that it may have been cut down from an elevation of 60 feet above tide. These estimates are not so reliable as they would be if the gaps were cut in a plain, because the moraine surface rises and falls, and a depression at a lower level than that indicated by the top of the steep valley side may have existed where these gaps now are." How- ever, it does not affect the results greatly whether the height of the barrier was a few feet more or less than the above estimates, but it is a matter of considerable importance to know whether the sea had access to the Hudson without an altitude of the land lower than the present, as the ice was retreating from the Brooklyn-Perth Amboy moraine. While it cannot be said to be demonstrable, the weight of the evidence seems to indicate that it did not. According to the hypothesis that the Hudson water body was an estuary, these gaps must have been first scoured out when the land was enough lower to permit the sea to enter and the tide to scour. This requires a depression Somewhat less, possibly, than 60 feet for the Narrows gap and 25–40 feet for the Arthur Kill gap. According to this hypothesis, tidal Scour must have lowered these gaps to such an amount that, on the subsequent uplift which permitted the sub- merged channels to be carved out, either there was free passage for the streams that flowed through them, or they were scoured to a level lower than that of any other part of the barrier, and thus took off the drainage which finished the work of cutting away the barrier. * Professor Salisbury has suggested that these steep slopes may be due to recent wave-action. If this be the correct explanation, it makes the amount of cutting of the gap through the moraine even less certain. If, however, the overwash plain fronting the moraine was once continuous across the Narrows, as seems likely, the altitude of its inner margin (20–40 feet A. T.) marks the minimum level from which the gap has been cut here. GLACIAL AND POST GLACIAL HISTORY 645 According to the hypothesis that the Hudson water body was a lake, these gaps were made by the outflow of fresh waters and not by tidal scour. This does not refer to the gaps at their present level, which may in part be due to tidal scour since the recent depression, but to their depth before the recent depression. If these gaps were cut by outflow of fresh waters, their relations are such as to require first a cutting as outlets of independent lakes, and later, when the ice had retired far enough to permit these independent water bodies to coalesce, either (1) they did coalesce or (2) the outlets had been cut enough to so lower the water-level of each that they remained inde- pendent. If the lakes coalesced, then either (a) one of the outlets had been cut lower than the other, and thus rapidly drew off the water below the level of the other, or (b) both persisted and were rivals in the task of draining the lake. In order that the requirements of the situation be clearly under- stood reference must be made to the maps showing the gaps and their relations to the present channels (see Fig. 8, p. 427, and Fig. 7, p. 425). From these maps it is observed that the Arthur Kill gap opens southward from Newark Bay, and that the Narrows gap opens southward from New York Bay. Newark Bay and New York Bay are connected by Kill van Kull ten miles north of Arthur Kill gap. New York Bay is connected with Long Island Sound by East River. The east end of Long Island Sound opens to the sea by wide channels. The land on the sides of both Kill van Kull and East River seems to indicate that the channels which they occupy have not been cut from much above sea-level. It follows, therefore, that if Arthur Kill and the Narrows gap were cut at first as outlets of independent lakes at the ice-front, and later as rival outlets of a water body that covered Newark Bay and New York Bay, they must either have been cut below the level of the divide between Long Island Sound and New York Bay before the ice retreated beyond it, or the present gap at the east end of Long Island must have been closed by a higher alti- tude of the land. Otherwise the Narrows gap at least would have been abandoned for a lower channel into Long Island Sound. While it is not at all unlikely that the gap at the east end of Long Island was closed, it is not essential for our present purpose to assume this. The writer, however, believes that the hypothesis that the present 646 CHARLES EMERSON PEET gap at the eastern end of Long Island was closed at that time by a greater altitude of the land is as tenable an hypothesis as any to account for the waters in which accumulated the Pleistocene clays of the Con- necticut Valley and other valleys opening into Long Island Sound. It is in harmony with the published facts in regard to the distribution of those clays." However, this is aside from the point under discussion. If the Narrows gap and Arthur Kill gap were started as outlets of independent lakes at the ice-front, then by the time the ice had retreated far enough to permit these water bodies to coalesce, either both had been cut below the divide now crossed by Kill van Kull, and had thus produced independent water bodies in Newark Bay and New York Bay, or they became rival outlets to a common water body. If they became rivals, then one of the following things happened: One of them drew off the water below the level of the other, or before either one was victorious both had succeeded in cutting below the level of the land along Kill van Kull, and thus produced independent water bodies (in Newark Bay and New York Bay). If one was victorious, the Narrows gap, since it finally became the deeper, presum- ably was the one. Under this interpretation the Newark Bay Lake became tributary to Hudson Lake. Arthur Kill may have remained, however, the channel of the Rahway-Woodbridge Creek system (see Fig. 8), and thus have been deepened more. In either event, the Newark Bay water body became independent and drained either through Arthur Kill or by way of Kill van Kull. The deposits in the lowlands west of the Palisade Ridge were made in this independent water body. If Arthur Kill remained the outlet, then the present Kill van Kull channel is due either to tidal scour or to the work of a tributary working back from the Hudson, or to both. If Arthur Kill was abandoned, and Kill van Kull was the outlet of this Newark Bay Lake, the present channel is due to cutting by the outflow of its waters and to subsequent tidal Scour, and Arthur Kill gap is due partly to cutting as an outlet of a lake, and later to cutting by the Rahway-Woodbridge Creek, and no doubt also to some recent tidal SCOUT. I See N. S. SHALER, J. B. WooDworthſ, AND C. F. MARBUT, “Glacial Brick Clays of Rhode Island and Southeastern Massachusetts,” Seventeenth Annual Report, U. S. Geological Survey (1895–96), pp. 957–IOO4. GLACIAL AND POST-GLACIAL HISTORY 647 If the submerged channels be accepted as inheritances from the past, and not due to tidal scour, or at least not enough to obscure their former relations, it would seem that the Hackensack-Passaic system, along with Elizabeth River, finally became tributary to the Hudson through Kill van Kull on the disappearance of Newark Bay Lake, and that the Rahway River with Woodbridge Creek formed a system flowing through the Arthur Kill gap. If the submerged channel outside the moraine south of Tottenville, likewise is an inheritance from the past and not due wholly to tidal scour, the Rahway-Woodbridge system was tributary to the Raritan, which, presumably, was tributary to the Hudson. The connection of the submerged Raritan and extra-morainic Hudson channel, however, cannot now be traced. 4. Scarcity of wave-wrought features in the Hudson Valley.—The almost complete absence of wave-wrought terraces in the area of the Hudson water body south of Glens Falls is not what would be expected. Even faintly developed terraces have been observed at a few places only. This apparent lack of effective wave-action may be due to the following: (I) In the presence of the ice-sheet the water body was frozen over for considerable periods of the year, and during the summer season the presence of floating ice would tend to reduce the effective- ness of the wind in producing waves. This explanation would apply on either hypothesis for the origin of the Hudson water body. It would be more applicable if the body was a lake, but would apply if the water body was the sea, and if much freshened as suggested below (p. 652), it would be nearly on a par with the action in a lake. (2) After the ice-sheet had retired to the northern part of the area, these conditions would no longer exist or would be much weakened in their effect and wave-action would be expected. (a) It is to be noted here, however, that the southern part of the area is the narrow part where the wind would have comparatively little chance to produce effective waves, even under the most favorable conditions of tempera- ture. The greater width of the water body in the northern part of the Hudson would seem to necessitate effective wave-action after the ice retired into the Lake Champlain region and the climate had become warmer, so that the surface was no longer frozen over for so large a part of the year. Too much emphasis, however, must 648 CHARLES EMERSON PEET not be placed on the warming up of the climate, for boreal willows in the Salmon River section indicate a climate considerably colder than the present in Marine Champlain time. (b) It is to be noted, also, that this wide northern part of the Hudson water body was divided into smaller portions by numerous islands and shoals (see Fig. 13, p. 437), and these would decrease the efficiency of the wind in producing waves. (c) If this water body disappeared shortly after the ice had reached the Champlain valley, the length of time for this effective wave-action was reduced, and the earlier the dis- appearance the more applicable the explanation becomes. If the Hudson water body existed until the ice had retired to near the Bouquet River, or beyond the Saranac, as is considered in the various hypothe- ses stated for the time of origin of the Higher Glacial Lake Champlain, then there was a long time for the production of shore terraces. The time necessary to make the secondary deltas noted on the Batten Kill and the Hudson River would seem to be ample for the develop- ment of distinct wave-wrought terraces, and it is in this part of the valley only that features have been observed that may be assigned to wave-action, but it is surprising that they are not better developed here. (d) There is evidence that the water-level was not constant. Possibly there were two things to make it inconstant: first, the cutting of the outlet, and, second, crustal movement. The first could be true, of course, only if the Hudson water body was a lake. The second could be true under either hypothesis for the origin of the water body, and, as mentioned above, is necessary for the disappear- ance of the water body under either hypothesis. Altogether the slight development of wave-wrought features in the Hudson is unexpected, and the above explanations do not seem to be wholly satisfactory, especially when it is recalled that under apparently very similar conditions distinct wave-wrought features were made in the Champlain region. The writer is forced to believe that a more detailed examination of the Hudson region will bring to light more evidence of wave-action. Features unexplained by the salt-water hypothesis.-Certain features are present which are in accord with the lake hypothesis, but not with the salt-water hypothesis. There are certain features not present which seem to be required by the latter hypothesis, but not GLACIAL AND POST-GLACIAL HISTORY 649 by the former. If the Hudson water body was an arm of the sea, the presence of some of these features and the absence of others must be accounted for. These features are: (1) absence of dis- tinct wave-wrought features at the outer edge of the Brooklyn-Perth Amboy moraine at the levels required by the hypothesis; (2) presence of the overwash plain on Staten Island and Long Island without distinct features to be ascribed to wave-action; (3) entire absence of life certainly marine in the deposits made in the Hudson water body; (4) apparent absence of tidal distribution of muds in the Hudson water body; (5) evidence of the altitude above sea-level of the Hudson water body. I. Absence of distinct wave-wrought features at the outer edge of Brooklyn-Perth Amboy moraine.—There is an absence of wave- wrought features of a decisive character outside of the moraine in a region where the materials are soft and easily washed and which must have been exposed to strong waves from the Atlantic. Although these materials are displayed with a topography which would not offer the best opportunity for effective wave-action, yet it seems incredible that the sea could have been present over the area outside of the moraine, at the levels demanded by the gaps in the moraine and for the time necessary for the tide to scour out these gaps to the required depth, without leaving a decisive record in the easily eroded drift. Three suggestions aiming at an explanation of this are as follows: (a) That these gaps were first made by the wearing of ice-waters before depression took place, and were subsequently deepened by tidal scour when the land had been depressed enough to admit the Sea. If this be admitted, the same early conditions as those under the lake hypothesis are assumed, the main difference being in the time of depression and in the number of depressions. (b) That ice pro- tected the shore from wave-action. This would seem plausible for the time when, and the places where, the ice was present, but is diffi- cult of acceptance after the ice-edge had retreated. Shore-ice might, however, have remained for long periods of the year, after the ice-sheet had retreated. (c) The land rose rapidly after the original depression, thus preventing the making of a distinct record of wave-action. If this was so, equally rapid Scouring of the channels must be postulated in order to accoount for the access of the sea to the Hudson Valley, 65o CHARLES EMERSON PEET It is doubtful if the rapid rise would be effective unless the movement was very rapid, and then the scouring would be handicapped. 2. Presence of the overwash plains at the ice-front.—The presence of the overwash plains at the ice-front on Long Island and Staten Island without distinct features to be ascribed to wave-action, or a form that the presence of the sea over them would lead one to expect, argues strongly for an altitude of land above sea-level when the over- wash plain was building. If the submergence hypothesis is tenable, it would seem necessary to assume access of the sea to the Hudson without submergence of the overwash plains. This necessitates an altitude of land at least as high as the present while these overwash plains were being made, and higher while the gaps were being cut to such a depth that on subsequent depression the Hudson water body was formed without submerging the overwash plains. The comple- tion of the gaps and the making of the channels now submerged are later events. 3. Absence of life certainly marine.—The only fossils that have been found in deposits in the Hudson water body are: (1) sponge spicules, fresh-water diatoms," and worm tracks at Croton; and (2) leaves of Vaccinia oxycoccus at Albany. No marine fossils have been found, unless the sponge spicules are such, and their identifi- cation, it seems, is uncertain. The presence of fresh-water diatoms is not necessarily fatal to the hypothesis of a salt Hudson water body, for they may have been brought into the salt water by the streams and deposited with the sediments in the salt water. If the sponge Spicules are those of Salt-water sponges, and if they were found in clays which antedate the recent depression, they settle the question of the origin of the Hudson water body.” Although there is an * See footnotes 3 and 4, p. 454. * These sponge spicules were reported from Croton by Mr. Heinrich Ries in 1895. Since the above was written and first placed in the hands of the printer, word has been received from Mr. Ries that the sponge spicules are those of species not confined to salt water. The exact locality at Croton from which the specimens came is also a matter of Some uncertainty. That they came from 20 feet below sea-level and were found in Solid lumps of clay is certain, however. Inasmuch as some of the clay used at Croton for brick-making has accumulated in the Hudson estuary since the recent depression, it is possible that the clay in which these specimens were found was deposited long after the disappearance of the Hudson water body, and that therefore the fossils mentioned have no bearing on the origin of the Hudson water body. GLACIAL AND POST-GLACIAL HISTORY: 651 entire absence of life certainly marine in the deposits of this time throughout the entire stretch of 240–265 and possibly more than 3oo miles through which the Hudson-Champlain water body extended (see Fig. 22), in the northern portion of the same region there is abundant evidence at low levels of marine life, which came up the St. Lawrence after the Hudson-Champlain water body had disappeared. Unless there is a sufficient explanation, this must be admitted as a strong argument against the Salt-water hypothesis. However, it must be admitted that there is likewise a paucity of any forms of life in the Pleistocene deposits of the Hudson Valley. In explanation of the absence of marine life in this hypothetical long arm of the sea three suggestions have been made: (1) The waters were cold while the ice was near. (2) The waters were muddy while the ice was near. (3) The waters were freshened because of the great territory—at one time the Great Lakes drainage basin—drained into this water body, and because of the shallow sill over which little salt water could pass. (I) In regard to the first suggestion it may be said that the waters were cold, but they were decreasingly cold as the ice retreated 240– 3oo miles and more northward. In Greenland, at the present time, marine life is abundant in the waters close to the ice-edge, so that even if the waters were cold it does not appear to be a sufficient reason for the absence of salt-water life. Further than this, marine life invaded the Champlain region soon after the ice had retreated across the St. Lawrence and permitted the sea to enter. The fact that it failed to do so during the much longer time it had to get into the Hudson from the south while the ice was retreating northward. argues strongly against the salt-water hypothesis. - - (2) The waters were muddy. This argument would hold good so long as the ice was near. When at a greater distance, the argu- ment does not hold good, for it seems to be true that there was com- paratively little deposition of muds at a distance from the ice. Were it not so, the kames and other ice-molded forms at low levels would have been buried. The presence of marine life in the clays on the coast of Maine, and also in somewhat younger clays in the Lake Champlain region, indicates that marine life could exist while the I Verbal communication of Professor Chamberlin. See also R. D. SALISBURY, Glacial Geology of New Jersey, p. 513. 652 - CHARLES EMERSON PEET deposition of considerable fine sediment was taking place. The explanation of the absence of life because of the muddiness of the waters therefore does not carry conviction with it, especially since there was so much opportunity for the introduction of life after the ice had retreated a great distance and the waters had become clear. (3) The water was kept fresh because of the shallow sills over which the salt water had little access. This is perhaps the best explanation offered." It necessitates a higher altitude at the east end of Long Island Sound than the present; otherwise there would have been abundant opportunity for life to come into the Hudson over the low land between Long Island Sound and the Hudson, and the Connecticut Valley deposits, which appear to resemble those of the Hudson in many respects, would be expected to show abundant marine life. It may be said, however, that this argument of shallow water over the sills has its limitations. It has been shown that it is necessary to believe that the channels through the moraine were cut down a con- siderable amount before the Hudson water body disappeared. On the submergence hypothesis tidal scour must be relied on to do this cutting, and reduction of the amount of water to get in over the sills at high tide reduces the amount that could go out with the ebb, and thereby proportionally reduces the efficiency of Scour; and if none comes in, the scouring is reduced to the action of the fresh water supplied by the streams. This limitation would be more severe in Newark Bay perhaps than in the Hudson, where the great amount of fresh water flowing from Lake Iroquois into the Hudson waters after the Rome outlet came into use would be available for Scouring the channel. The argument would not apply so well, however, in explanation of the absence of marine life in the Connecticut Valley. The demands of later events require a scouring out of the Hudson channel at the Narrows to a considerable depth—possibly as much as 132 feet—before the Hudson water body disappeared. It would seem that this amount of scour would admit plenty of Salt water and marine life. It may be, however, that water in the scoured channel was kept shallow by uplift, and the supply of salt water was thereby limited. Altogether it would seem possible that the explanation I See R. D. SALISBURY, Glacial Geology of New Jersey, Final Report of the State Geologist, Vol. V, pp. 51 I-I3. GLACIAL AND POST-GLACIAL HISTORY 653 offered might account for the absence of marine life in the Hudson, if the delicate adjustment required to keep the water shallow over the sills existed. It is not known, however, that the conditions postu- lated actually did exist. The explanation would not apply to the phenomena in Long Island Sound, and in the Connecticut Valley, if the altitude of the land was as low as at present. It is doubtful if it is adequate even for the Hudson Valley phenomena without a higher altitude of land at the east end of Long Island Sound. This higher altitude is a requirement of the same kind, and nearly as great, as for the lake hypothesis in both the Hudson and Connecticut Valleys, and greater than required for the Hudson Lake alone, which could have existed without this eastern uplift. 4. A fourth argument against the Salt-water body is the absence of tidal action indicated by the fact that fine sediments were apparently not carried to any great distance from the ice-front. This is shown by a failure to bury some of the kames and other ice-molded features at low levels adjacent to higher gravel, sand, and clay. It may be said that this apparent failure of the fine sediments to be carried out on older and lower deposits in some situations, especially in the southern Hudson, is so extraordinary as to tax even the lake hypoth- esis. In some places this may be explained, however, by the per- sistence of protective stagnant ice-masses. There may be a question whether stagnant ice-masses would endure long enough to be thus effective. 5. A fifth point bearing on the hypothesis that the Hudson water body was an arm of the sea is the evidence presented by its altitude when Higher Glacial Lake Champlain was separated from it. The evidence goes to show that its altitude at this time was some- thing less than 200 feet above tide. How much less is unknown. If the amount of uplift while Higher Glacial Lake Champlain was being drained could be determined, the altitude of the Hudson water body when the barrier south of Fort Edward appeared would follow. (See pp. 640, 641.) WHAT EVIDENCE IS THERE THAT THE HUDSON WATER BODY WAS A LAKE P If the existence of a body of standing water be admitted, all the arguments against the Submergence or Salt-water hypothesis throw the scales in favor of the lake hypothesis. The evidence in favor of the 654 CHARLES EMERSON PEET lake hypothesis is as follows: (1) the existence of a barrier; (2) the evidence of deep channels cut through that barrier and submerged channels of drainage both inside and outside the barrier; (3, 4, 5, 6, 7) the five points mentioned above, as opposed to the salt-water hypothesis. 1. The existence of a barrier makes the lake possible.—Under the Sea hypothesis it also makes it necessary to explain the gaps in the barrier as, in part at least, due to tidal scour—an action which may have been limited (see the explanation for the absence of marine fossils as due to the shallowness of the water over the sills giving access to the Salt water, p. 652). A barrier at the east end of Long Island Sound is not necessary for the existence of Lake Hudson, but an altitude of the land higher than now in that region is required by the supplementary explanation attached in this article to the salt- water hypothesis, and an altitude but little greater would produce a lake, and thus bring the Connecticut Valley phenomena and Hudson Valley phenomena under one explanation. It is not meant to imply here, however, that the Hudson and Connecticut water bodies were one water body. It seems certain that if they were at an early date, they became independent later. 2. The channels through the barrier and the submerged channels tnside and outside the barrier.—Under the lake hypothesis the outlet valley was a necessary feature, and the submerged channels are the natural Consequences of the drainage of the lake, Subsequent erosion by the Hudson, and later depression. Under the salt-water hypothesis the gaps must be explained as due to tidal Scour which extended to a depth great enough to let the streams flow through them when eleva- tion had taken place, but the completion of the channels was by the erosion of the Hudson at the subsequent higher stand of the land and perhaps by recent tidal Scour. The lake hypothesis makes the gaps and extra-morainic channels now submerged, contemporaneous, in part at least, with the existence of the lake. The salt-water hypothesis makes them due in part to tidal Scour, and in part to erosion following the uplift of the land and the consequent recession of the sea. The channels inside the moraine in Newark Bay may be contem- poraneous with the later history of the Hudson Lake. Under the GLACIAL AND POST-GLACIAL HISTORY 655 salt-water hypothesis they follow uplift, but may be contempora- neous with deltas in the upper Hudson. The fact that the disappear- ance of the Newark Bay water body followed an uplift of the land of just about the amount necessary to cause this water body to dis- appear favors the submergence hypothesis (see p. 659). ARGUMENTS OPPOSED TO THE HUDSON LAKE HYPOTHESIS. There are two possible arguments against the lake hypothesis. One of them is based on the altitude of land farther south in New Jersey. Certain terraces on the south shore of Raritan Bay and south form in part the basis for belief in the lower altitude of land in that part of New Jersey, but such terraces are not found on the drift-covered north side of Raritan Bay." This would indicate that the submergence which produced the terraces on the south side of Raritan Bay came earlier, and that, if it extended to the north side, emergence had taken place before the ice retired. Professor Salis- bury assigns the date of the submergence which produced these ter- races either to late glacial or post-glacial time,” but he considers the question of submergence in the vicinity of New York as still an open one. The absence of distinct wave-wrought features on the Brooklyn-Perth Amboy moraine and on the overwash plain between Brooklyn and Perth Amboy does not favor the hypothesis of sub- mergence there, and it is difficult to reconcile the absence of these features with the hypothesis of a lower altitude of land. There is another objection to the lake hypothesis which, if it were valid, would argue for the Salt-water hypothesis. It is that the south- ern barrier could not have lasted during the great time it took to make the clays in the region north of the moraine. As will be seen from the discussion of the origin of the gaps in the moraine, if the barrier consisted of the moraine only, and was limited to that part of the moraine above present sea-level, it must be admitted at once. It must be remembered, however, that at the time of maximum south- ern elevation the outlet stream was cutting through a wide stretch of land outside the moraine. As mentioned before, the shore line of this time may have been 95–IOO miles farther South. It is very likely, I G. N. Knapp, verbal communication. 2 Glacial Geology of New Jersey, p. 204. 3 See New York City Folio, U. S. Geological Survey, p. 16. 656 CHARLES EMERSON PEET also, that the outlet was never very high above sea-level, but that the uplift was taking place while the ice was retreating, so that the rate of cutting of the barrier would be kept close to a minimum. It must be remembered also that the character of the lower portions of the channels through the moraine is unknown. It may well be is ºf FIG. 27.-New York and vicinity as it would appear if depressed enough to permit the entrance of the sea over the probable original height of the barrier at the Narrows and at Perth Amboy, and if the depression south of the Raritan River were forty to fifty feet. Black color indicates land not covered by waters during the hypothetical depression. The outline represents the present coast. that it is of such a nature as to resist erosion. It would be expected, indeed, that after a certain amount of erosion of the moraine the GLACIAL AND POST-GLACIAL HISTORY 657 concentration of the larger bowlders which are common in moraines would form a pavement in the bottom of the channel and would check the down-cutting. - In conclusion, it may be stated that, while no single argument seems to be fatal to the salt-water hypothesis accounting for the Hudson water body, unless those drawn from the phenomena on the outside of the moraine be such, it is likewise true that the facts are not fatal to the lake hypothesis, unless the sponge spicules reported from Croton represent salt-water species.* Aside from these sponge spicules, the weight of the evidence seems to be in favor of the lake hypothesis. RELATION OF HUDSON WATER BODY TO THE CONNECTICUT WALLEY WATER BODY. . If the Hudson water body was an arm of the sea, there is no need of discussing the relation between the Connecticut Valley deposits and those of the Hudson more fully than they have already been discussed. It is enough to repeat here, what has been said before (p. 652), that in order to account for the absence of life certainly marine in the Hudson, on the hypothesis stated above (p. 652), it seems necessary to postulate a higher altitude of the land at that time at the east end of Long Island Sound, so as to shut out free access of salt water to both the Connecticut Valley and the Hudson Valley. If the Hudson water body was a lake, it does not necessarily follow, of course, that the Connecticut Valley deposits accumulated in a lake. This explanation is given for these deposits in Massachu- setts.” It is true nevertheless that a southern uplift somewhat more than that necessary to make Hudson Lake would equally well account for the phenomena of the Connecticut Valley. So far as published accounts indicate, there is little, if any, clay of late glacial age, outside of the area north of Long Island Sound, which could not be explained as having accumulated either in local lake basins, or in the sea when the land at the north was depressed enough to submerge the clay areas along the eastern New England coast. This northern depres- * See footnote, p. 650. * See EMERSON, Monograph XXIX, U. S. Geological Survey, Chap. 19. 658 CHARLES EMERSON PEET Sion is not incompatible with the southern uplift which would produce a lake in Long Island Sound and in the valleys and lowlands north of it. If Long Island and the land to the east were high enough to make a lake north of it, either from the start or later on, this water body was divided into several parts. RELATION OF HUDSON WATER BODY TO WATER BODY WEST OF PALISADE RIDGE. As already indicated, if the Hudson water body was an arm of the sea, so also were the waters in the lowland west of the Palisade Ridge by the time the ice had retired beyond the Sparkill Valley or earlier. If the Hudson water body was a lake, the waters west of the Palisade Ridge," which may be called Newark Bay Lake, were probably inde- pendent while the ice was present, and either drained through Arthur Kill, or first through that outlet and later into the Hudson by Kill van Kull. This Newark Bay Lake, nd doubt, disappeared long before the Hudson Lake. It is interesting to note that when the ice had retreated beyond the Sparkill Valley, which crosses the Palisade Ridge just north of the New Jersey boundary (Fig. 9, No. 14, p. 429), the waters of this Newark Bay water body coalesced with those of the Hudson water body through this narrow valley, the bottom of which is now 20–30 feet above tide at the west side of the Palisade Ridge. Since the land was at this time down at the north by 75–90 feet more than at the south, it follows that this Sparkill Valley was the lower outlet, and that when the Hudson water body had been lowered to the level of this valley, the Newark Bay water body disappeared. What- ever cutting, therefore, was done at a Southern outlet was accom- plished before the ice had retired beyond this valley. It is likewise interesting to note that with this amount of northern depression the slope of the Hackensack Valley floor, for instance, would have been just the reverse of the present. If, when the water body disappeared this was true, the lower Hackensack, for instance, and other streams would have flowed in the reverse of their present direction and joined the Hudson water body through the Sparkill Valley. Since thcre is no evidence, so far as the writer is aware, that such a reversal has taken place, it would follow that by the time the Newark Bay water 1 For discussion of hypotheses to account for this water body see R. D. SALISBURY, Glacial Geology of New Jersey, pp. I95-200. GLACIAL AND POST-GLACIAL HISTORY 659 body disappeared there had been an uplift sufficient to produce a slope southward. That uplift must have been as much as 45–60 feet, and may have been more. Since the water-level must have been lowered this same amount in order to disclose the floor, it would seem that the disappearance of the water in this area was due to uplift. This may have been true under either origin of the water body, and must have been true under the estuarine hypothesis. The early history of this water body was in part contemporaneous with that of Lake Passaic," but the latter lake had disappeared before the Newark Bay water body had attained its greatest dimensions. When the Newark Bay water body disappeared, the floor was exposed as a broad stretch of plain partly covered with sand, through which the Passaic-Hackensack River took its course and was joined east of Shooter's Island by the extended course of Elizabeth River. From the sands of this Newark Bay lake-floor the dunes which occur on the west side of Newark Bay at various places were made.” If the peat under this Sand is a salt marsh accumulation, as Professor George H. Cook thought, the interpretation must be altered accord- ingly. RELATION OF HUDSON WATER BODY TO LAKE IROQUOIS. The delta of the Mohawk River in the Hudson water body is reported at 340 feet above tide.” If this was made at a time when Lake Iroquois was draining out through the Rome outlet, it shows that the Hudson water body had a level lower than Lake Iroquois, by an amount, however, not necessarily the same as the present difference between the Lake Iroquois level and the delta level. If Higher Glacial Lake Champlain was inaugurated before the ice retired beyond the Adirondacks, then here is the only opportunity to determine the relation between the levels of Lake Iroquois and the Hudson or Hudson-Champlain water body. If Higher Glacial Lake Champlain was not inaugurated until after the ice retired beyond the I See ROLLIN D. SALISBURY AND HENRY B. KUMMEL, “Lake Passaic: An Extinct Glacial Lake,” Annual Report of the State Geologist of New Jersey for 1893, pp. 225–328. * See Geology of New Jersey, 1868, p. 228, and Annual Report of New Jersey State Geologist, 1893, p. 205. 3 A. P. BRIGHAM. 66o CHARLES EMERSON PEET Adirondacks, then the waters of Lake Iroquois must have fallen to the level of Hudson-Champlain, and subsequently had the same level as that of Higher Glacial Lake Champlain on the uplift of the barrier south of Fort Edward. The weight of the evidence, however, is against this succession of events. RELATION OF HIGHER GLACIAL LAKE CHAMPLAIN TO IROQUOIS. Lake Iroquois was made by the ice blocking the St. Lawrence and causing the waters in the Ontario basin to overflow at the lowest point of the basin which was then near Rome, N. Y. During the retreat of the ice a differential uplift was in progress greater at the north. G. K. Gilbert says that when the Rome outlet (present level, 44o feet above tide) was abandoned at the close of the Iroquois epoch, “the water of the Ontario basin descended for a time along a course beginning near Covey Hill, and ending near West Chazy, N. Y.” Whether these levels are marked by shore terraces is not stated. If they are, it would seem that when the ice retired far enough north in the Champlain Valley, the waters of the Ontario and Champlain basins coalesced. This water body might properly be called Lake St. Lawrence—a name suggested by Upham in 1895.” If these levels are not marked by shore terraces, but simply by a series of outlet levels, 3 then it would seem that the waters of Higher Glacial Lake Champlain and the successor to Lake Iroquois did not coalesce, at any rate not until the close of Higher Glacial Lake Champlain time, when both fell to the levels which have been called “Marine” Cham- plain levels although the highest of these levels do not seem to contain marine fossils (see p. 626). During “Marine” Champlain time these waters not only occupied the Champlain Valley, but extended into the Ontario basin, as is shown by the fact that the “marine” shores of the Champlain Valley extend westward through northern New York to the Ontario basin, being continuous with the so-called Oswego shore line.” In the Ontario 1 Eighteenth Annual Report, U. S. Geological Survey, Vol. I, p. 59. a See American Journal of Science, Vol. CXLIX (1895), pp. I-18; Monograph XXV, U. S. Geological Survey, p. 264. See also this article, p. 626. 3 Since this was written and placed in the hands of the printer the writer has learned from conversation with Mr. Gilbert that this is the fact. 4 G. K. GILBERT, loc. cit. GLACIAL AND POST-GLACIAL HISTORY 66I basin as in the Champlain basin there is evidence of differential uplift greater at the north, in the late stages of the ice-retreat. DURATION OF HUDSON WATER BODY. If the Brooklyn-Perth Amboy moraine be correlated with the earliest Late Wisconsin terminal moraine, the history of the Hudson water body spans, or more than spans, the history of the entire system of moraines of that time represented in Ohio, Indiana, and Illinois. In terms of the history of the succession of the Great Lakes, it spans or more than spans, the history of Lakes Maumee, Whittlesey, War- ren, Dana, and part of Iroquois," and possibly all of the latter, accord- ing to the interpretation of the time of inauguration of Higher Glacial Lake Champlain. In terms of the history of Lake Chicago, it began earlier, and whether it ended earlier or later depends on the time the northern outlet of Lake Chicago was opened up by the retreat of the ice. TIME DIVISIONS. If the beginning of the retreat of the ice from the Brooklyn-Perth Amboy moraine be counted as Champlain time, then the time since the moraine was made may be divided as follows: Hudson-Champlain. Higher Glacial Lake Champlain. St. Lawrence-Champlain. Marine Champlain. 5. Present Lake Champlain. The St. Lawrence-Champlain time would include the time from the abandonment of the Fort Edward outlet to the fall of the water- level to the sea-level. : CHARLES EMERSON PEET. LEWIS INSTITUTE, Chicago. * For an account of the history and relations of these lakes see LEVERETT, Mono- graph 41, U. S. Geological Survey, pp. 7 Io-75.