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Rh Reelevation of the St. Lawrence river basin. 5

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 ice- sheet 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, Illi- nois, 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 JSTelson 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. P. B. Taylor, this Journal, III, vol. xliii, pp. 210-218, March, 1892 (Mackinac island); Bulletin Geol. Soe. 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. B.Andrews, " The North American Lakes considered as Chronometers of Postglacial Time," Trans. Chicago Academy of Sciences, vol. ft. Nearly all the edition of this im- portant paper was consumed in the Chicago fire of 1871. It is quite fully re- produced 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 sec- tions). N. H. Winchell, J. S. Newberry, E. W. Claypole, and G. P. 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.