Cleveland. Northeast and north from the old outlet the Leipsic beach reaches about 165 miles, past Adrian and Ypsilanti to Imlay, Mich., being nearly level to Ypsilanti, but thence in the 60 miles onward to Imlay having a rise of about 65 feet, to an altitude 849 feet above the sea. With the reces

sion of the ice-sheet and the extension of this lake to Imlay, a lower outlet was opened over the watershed between the Shiawassee and Grand rivers in Michigan, 729 feet above the sea or 148 feet above Lakes Huron and Michigan, where the Western Erie glacial lake became confluent with Lake Warren and was thus reduced about 30 feet, falling from the Leipsic or lower Western Erie beach to the Belmore or earliest beach of Lake Warren in the Erie basin.

Upon a large area, extending from Ft. Wayne east to Cleveland and northward to Ypsilanti and Detroit, the attitude or general slopes and levels of the land have remained unchanged since the departure of the ice-sheet, for these earliest beaches and the lower beaches of Lake Warren in the same area are still nearly horizontal. The whole country there, however, has been uplifted, without tilting, about 110 feet, after the end of the separate existence of the Western Erie lake, for this is the height of the Belmore beach around the west end of Lake Erie above the highest and earliest beach of Lake Warren at Chicago. A greater and differential uplift, with rapid tilting of northward ascent, was taking place north and northeast of Detroit during the Belmore and lower stages of Lake Warren, simultaneous with the uniform elevation of the Western Erie glacial lake area. Further we learn that about half of the uplift of 110 feet for this region had occurred before the beginning of Lake Algonquin and the date of the Algonquin beach, since that beach has a height of 602 feet near the south end of Lake Huron, being 60 feet higher than the correlative sublacustrine terrace plane beneath the surface of Lake Michigan near Chicago, which marks the old Algonquin shore there.

Lake Warren.*-Like the Western Superior and Western

* J. W. Spencer, Science, vol. xi, p. 49, Jan. 27, 1888 (proposing this name in honor of Gen. G. K. Warren); Proc. A. A. A. S., vol. xxxvii, for 1888, pp. 197199; Trans. Roy. Soc. of Canada, vol. vii, for 1889, sec. iv, p. 122; this Journal, III, vol. xli, pp. 201-211, with map, March, 1891; Bulletin, Geol. Soc. Am.. vol. ii, pp. 465-476, with map, April, 1891; "A Review of the History of the Great Lakes," Am. Geologist, vol. xiv, pp. 289-301, Nov., 1894 (containing citations of many additional papers by Prof. Spencer and others). G. K. Gilbert, "Changes of Level of the Great Lakes," in The Forum, vol. v, pp. 417-428, June, 1888; "History of the Niagara River," in Sixth Annual Report of the Commissioners of the State Reservation at Niagara, for 1889, pp. 61-84, with eight plates (also in the Smithsonian An. Rep. for 1890, pp. 231-257); Geology of Ohio, vols. i and ii. Frank Leverett, paper before cited; "Raised Beaches of Lake Michigan," Trans. Wisconsin Academy of Sciences, Arts, and Letters, vol. vii, pp. 177-192 (read Dec. 30, 1887). A. C. Lawson, "Sketch of the Coastal Topography of the North Side of Lake Superior, with Special Reference to the

Erie glacial lakes, the far more extensive Lake Warren at the beginning of its existence occupied only the southern end of the basin of Lake Michigan. It grew northward as the icesheet retired, and in due time it received these two lakes to itself, expanding thus into the basins of Lakes Superior, Huron, and Erie. The maximum development of Lake Warren stretched from Thomson, Minn., above and west of Duluth, eastward to Lake Nipissing, a distance of nearly 600 miles; and from Chicago, where it outflowed to the Des Plaines, Illinois, and Mississippi rivers, it extended eastward in its highest stages across the southern peninsula of Michigan, and later by way of the strait of Mackinaw and over Lakes Huron, St. Clair, and Erie, to the west end of the Lake Ontario basin and to Crittenden in southwestern New York. This area exceeded 100,000 square miles, being nearly equal to that of the glacial Lake Agassiz. The Belmore and Nelson beaches, the two highest formed by Lake Warren in the basins of Lakes Erie, Huron, and Superior, called by Spencer the Ridgeway beach (a later name than N. H. Winchell's "Belmore ridge") in their united course about the west half of Lake Erie, show that, since the fullest expansion of this great glacial lake, the whole basin of Lake Superior and the country eastward to Lake Nipissing have been uplifted 400 to 550 or 600 feet, in comparison with Chicago and the southern part of the Lake Michigan basin, while the uplift at Cleveland has been about 115 feet, and at Crittenden, N. Y., not less than 260 feet (more probably about 300 feet).

In the vicinity of Chicago, Lake Warren formed three beaches, belonging to lake levels successively about 45 to 50 feet, 15 feet, and 30 feet above Lake Michigan. That the Abandoned Strands of Lake Warren," Minnesota Geol. Survey, Twentieth An. Rep. for 1891. pp. 181-289, with map, profiles, and figures from photographs. F. B. Taylor, this Journal, III, vol. xliii, pp. 210-218, March, 1892 (Mackinac island); Bulletin Geol. Soc. Am., vol. v, pp. 620-626, with maps, April, 1894 (Lake Nipissing): Am. Geologist, vol. xiii, pp. 316-327 (Green bay) and 365-383 (south coast of Lake Superior), with maps, May and June, 1894; id., vol. xiv, pp. 273-289 (east of Georgian bay), with map, Nov., 1894. The highest beach on Mackinac island, which Mr. Taylor calls the " Algonquin beach," seems to be correlative with his Nelson and higher beaches in the vicinity of Lake Nipissing, regarded in this paper as marking the early high stages of Lake Warren. C. Whittlesey, Smithsonian Contributions, vol. xv, 1864, pp. 17-22. E. Andrews, "The North American Lakes considered as Chronometers of Postglacial Time," Trans. Chicago Academy of Sciences, vol. ii. Nearly all the edition of this important paper was consumed in the Chicago fire of 1871. It is quite fully reproduced by James C. Southall, in "The Recent Origin of Man," 1875, chapter xxxiii (pp. 495-506, with sections); and in "The Epoch of the Mammoth and the Apparition of Man upon the Earth," 1878, chapter xxii (pp. 348-367, with sections). N. H. Winchell, J. S. Newberry, E. W. Claypole, and G. F. Wright, as before cited. Geol. Survey of Canada, Report of Progress to 1863, pp. 912, 913. Warren Upham, Bulletin Geol. Soc. Am., vol. ii, pp. 258-265; vol. iii, pp. 484– 487. Geology of Minnesota, Twenty-second An. Rep. for 1893, as before cited. Am. Geologist, vol. xiv, pp. 62-65, July, 1894.

beach at 30 feet was formed after that at 15 feet is shown by the occurrence in some places of a peat deposit, described by Andrews and Leverett, which passes underneath the 30 feet beach and is continuous from its upper side down to the lower beach. The peat marks a land surface over which the lake rose to form the middle or third beach, after having stood at the lower or second beach for some time. Still later, however, it probably again stood at the lower level, corresponding to the present watershed in the abandoned outlet. This old channel of outflow, at its summit, as I am informed by Mr. Ossian Guthrie from the canal survey, is now 11 feet above the mean level of Lake Michigan, but the surface there is postglacial silt; at another point, where the channel bed consists of till, and at a third place where the bed is rock, its height in each case is only eight feet above the present lake, or 590 feet above the sea. The mouth of Lake Warren appears to have been at first near Lemont, on the Des Plaines river about 25 miles from the lake, where the river valley was obstructed by drift which suffered erosion, allowing the mouth of the lake to be transferred gradually upstream, at the same time being lowered, to its final position ten miles from the lake shore in Chicago. Epeirogenic movements, between the times of formation of the second and third beaches, slightly lifted the outlet and adjacent portion of the course of the Des Plaines river, as compared with the southern and southwestern part of the Lake Michigan basin, causing the old lake to extend a little farther on that side than before. Toward the north and east, however, this change was doubtless more than counteracted by the rapid differential rise of the land.

Fresh-water shells are found abundant in the 15 feet beach at Evanston and elsewhere southward through Chicago. All the species obtained, representing ten or more genera, are still living in this region. Wood of oak and cedar, and the thigh bone of a deer, have been also found in the same beach at Evanston.*

For the distance of about 185 miles from Chicago north to the south end of Green bay, the highest shore of Lake Warren appears to be now nearly level, for Mr. Taylor finds evidence of submergence only to a height of some 20 feet above that part of Green bay and the neighboring lake shore. Thence northward, however, the beach rises about 14 feet per mile for 110 miles to Cook's Hill, near the north end of this bay; in 60 miles from that latitude north to Houghton, it has an ascent of 260 feet, or 4 feet per mile; but in about 90

* H. M. Bannister, Geology of Illinois, vol. iii, 1868, pp. 241, 242. F. Leverett, "Raised Beaches of Lake Michigan," before cited, p. 189.

miles onward, across Lake Superior to Kaministiquia, where the shore is 455 feet above that lake, the rate of northward ascent is reduced to only a half of a foot per mile.

Along a west to east course, the Nelson beach (named by Taylor in the vicinity of North Bay, Lake Nipissing, probably not distinct from the Belmore beach in Ohio and northward to Mackinac island) is 385 feet above Lake Superior at Duluth; 410 feet at Houghton, having an eastward ascent of 25 feet in 150 miles; 414 feet at the Sault Ste. Marie, running level for 200 miles east from Houghton; and about 538 feet at the north side of Lake Nipissing, or 497 feet above that lake, and 1,140 feet above the sea. In the distance of 220 miles from Sault Ste. Marie to Lake Nipissing this beach now shows an ascent of 126 feet, or about seven inches per mile. These figures, with the preceding from Houghton to the north side of Lake Superior, justify to a remarkable degree Dr. Lawson's opinion that the ancient shore lines of Lake Warren in the Superior basin remain parallel with the water level of to-day. As compared with Chicago, the country enclosing Lake Superior has been uplifted 400 to 450 feet; and the greater part of the differential elevation, expressed by tilting, took place upon the west to east belt of the northern peninsula of Michigan.

Three beaches of Lake Warren are mapped by Spencer and named the Ridgeway, Arkona, and Forest beaches in Ohio, northwestern Michigan, and the province of Ontario north of Lake Erie. These probably represent the three noted at Chicago and about the south part of Lake Michigan. Farther north the number of distinct shore lines is much increased. In and near Duluth I find eight beaches referable to Lake Warren, the lowest being 50 feet above Lake Superior. On northern portions of the Lake Superior coast several of these seem, as shown by Lawson's observations with leveling, to be each represented by two or more shores, separated by vertical intervals of 10 feet or more. Most of the northern beaches, it should be remarked, are very feebly developed, even in the most favorable situations for their formation, and are not discernible along the far greater part of the lake borders. During all the time of differential uplifting of the Lake Warren basin and sinking of the water surface, whenever the diminishing lacustrine area was nearly unchanged for a few years or longer, the erosion and deposition effected by the great waves of storms, and the tribute of streams forming deltas, recorded these shore lines.*

* Prof. Spencer, in his latest paper ("A Review of the History of the Great Lakes," Am. Geologist, vol. xiv, pp. 298, 301, Nov., 1894), supposes that an outflow from Lakes Superior, Huron, Michigan, and Erie, passed by the way of

Lake Algonquin.*-When the glacial melting and retreat at length permitted an outflow from the St. Lawrence basin over a lower pass, which was through central New York to the Mohawk and Hudson, the water surface of the basins of Lakes Michigan, Huron, and Superior, fell only some 50 or 75 feet, from the latest and lowest stage of Lake Warren to its shortlived successor, Lake Algonquin. This lake appears to have been ice-dammed only at low places on its east end, as at or near the heads of the Trent and Mattawa rivers, lying respectively east of Lakes Simcoe and Nipissing, where otherwise its waters must have been somewhat further lowered to outflow by these passes. Careful study and comparison of the work of Spencer in tracing the Algonquin beach about the southern part of Lake Huron and Georgian bay, and of Taylor in exploration of his "Nipissing beach" from Duluth east along the south coast of Lake Superior and the north side of Lake Huron and Georgian bay to Lake Nipissing, convince me that these beaches were of contemporaneous formation, marking respectively the southern and northern shores of Lake Algonquin, and therefore both to be known by the name Algonquin beach of Spencer, according to the law of priority. The earliest and principal stage of Lake Algonquin is shown by these beaches to have coincided closely in area with Lakes Michigan and Superior, but to have been considerably more extensive eastward than the present Lake Huron and Georgian bay. It held a level which now by subsequent differential epeirogenic movements is left probably wholly below the level of Lake Michigan by a vertical amount ranging from almost nothing to about 40 feet. Its shores were nearly coincident with the western shore of Lake Huron, but eastward they are now elevated mostly 150 to 200 feet above that lake and Georgian bay; and in the Lake Superior basin they vary from about 50 feet above Lake Superior at its mouth, and along its northeastern and northern shores, to 25 feet at Houghton, and to a few feet or none at Duluth.

The Algonquin beach at the south end of Lake Huron coincides very closely with the land surface there and with the

Chicago to the Des Plaines and Mississippi rivers so lately as about 1,500 years ago, when the Niagara river had cut back its gorge to the Johnson ridge, about a mile north of the present site of the falls. This would have formed a beach 10 to 15 feet above Lakes Michigan and Huron, and about 20 to 25 feet above Lake Erie, around all their shores; and the absence of such a modern and still horizontal shore line, slightly higher than the present lake levels, upon all this large area, forbids an acceptance of this hypothesis.

* J. W. Spencer, "Deformation of the Algonquin Beach, and Birth of Lake Huron," this Journal, III, vol. xli, pp. 12-21, with map, Jan.. 1891; and other papers before cited. G. K. Gilbert, F. B. Taylor, and Warren Upham, as before cited for Lake Warren. G. F. Wright, Bulletin Geol. Soc. Am., vol. iv, pp. 4235; with ensuing discussion by Dr. Robert Bell, pp. 425-7.