Page:The American journal of science, series 3, volume 49.djvu/22

4 4 W. Upham — Champlain Subsidence and

Cleveland. Northeast and north from the old outlet the Leipsic beach reaches about 165 miles, past Adrian and Ypsi- lanti 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 Cleve land 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 up- lift of 110 feet for this region had occurred before the begin- ning 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 subla- custrine 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

honor of Gen. G. K. Warren); Proc. A. A. A. S., vol. xxxvii, for 1888, pp. 197- 199 ; 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
 * J. W. Spencer, Science, vol. xi. p. 49, Jan. 27, 1888 (proposing this name in