DEPARTURK OF ICE-SHEET- FROM THE LAURENT! AN LAKES. 23 



Eiglit lower sliorelino?!, formed after the Western Superior lake was merged with 

 the more extensive lake Warren, are marked in and near Duluth hy small beach 

 ridges on portions of tlie (^Id lake shores situated favorably for their accumulation, 

 and by dehas of inflowing streams. A fine succession of these deltas was ol)served 

 along the coni-se of Cliester creek, through the city of Duluth, in its descent from 

 its high valley cut in the upi)er i)art of the blufls. To present concisely the results 

 of my studies for the Minnesota Geological Survey* of the whole series of lake 

 shores observed by me in the vicinity of Duluth and their jorobable correlations 

 with the shores observed farther eastward by Dr A. C. Lawson,t Mr F. B. Taylor,| 

 Professor J. W. Spencer | and others, the}' are arranged a little farther on in their 

 descending oi'der, with notes of their altitudes at numerous places in feet above 

 lake Superior, The observations along the north coast of this lake are by Dr Law- 

 son ; on Isle Royale and in part on the Keweenaw peninsula, by Dr A. C. Lane, 

 from unpublished work for tlie Michigan Geological Survey ; and along the southern 

 coast of lake Superior, about Green bay of lake Michigan and eastward to lake 

 Nipissing, by ^Ir Tayl(jr. On northern portions of the lake Superior coast several 

 of these old lake levels seem to be each represented by two or more shores, sepa- 

 rated by vertical intervals of 10 feet or more. Most of the beaches, it should be 

 remarked, are very feebly developed, even in the most favorable localities for their 

 formation, and are not discernible along the greater part of all the lake borders. 



BEACHES OF THE MESTEIiX SUPERIOR GLACIAL LAKE AXD THEIR ALTITUDES 



First Duluth Beach. — At Duluth, 535 feet above lake Superior; on mount Joseph- 

 ine, 607 feet; at Kimball, Wis., 570 feet; and at L'Anse and Marquette, Mich., 590 

 feet. 



Second Duluth Beach. — At Duluth, 515-510 feet; on mount Josephine, 587 feet. 



Boulevard Beach. — At Duluth, 475-470 feet; on mount JoseiDhine, 509 feet. 



BEACHES OF THE GLACIAL LAKE h'ARREX ASD THEIR ALTITUDES 



Belmore Beach. — This name was given by Professor N. H. AVinchell to the corre- 

 sponding earliest shoreline of lake Warren in Ohio. Near Wrenshall and in 

 Duluth, 410-415 feet; Grand Portage, 440 feet; on the Kaministiquia river, 455 

 feet ; at ^lackenzie, on the Canadian Pacific railway 13 miles northeast of Port 

 Arthur, Dr Lawson's descriptions indicate that this lake level, at about 475 feet, 

 adjoined the melting ice-sheet (1. c, i)age 204) ; eight miles east of Cartier, about 

 600; southeast of lake Nipissing, ()05-()20. The Ridgeway beach of Professor 

 Spencer. 



Nehon Beach. — Named by Taylor in the vicinity of North Bay, lake Nipissing; 

 probably united with the Belmore beacli in Ohio and northward to INLxckinac 

 island. At Duluth, 385 feet; at Mackenzie, a morainic terrace, 420 feet; at Jack- 

 fish bay, 418 feet; at Cook's mill, north of Green bay, lake Michigan, 150 feet; 



♦Geol. and Nat. Hist. Survey of Minnesota, Twenty-.second An. Rep., for 1893, pp. 54-GG. 



t" Sketch of the Coastal Topography of tlie North Side of Lake Superior, with special reference 

 to the Abandoned Strands of Lake Warren," Minnesota Twentieth An. Rep., pp. 181-289, with plates, 

 map and sections. 



J "The Ancient Strait at N'ipissing," Bulletin Geol. Society of America, vol. v, pp. r,20-n2r., April 

 1894 ; " Reconnaissances of the Abandoned Shorelines of Green Bay and of the South Coast of Lake 

 Superior," Am. Geologist, vol. xiii, pp. .'$10-327 and 3r,.')-383, with maps. May and .Tun*', 1894. 



§ Am. .Jour, of Science, Dec., 1890, Jan. and March, 1891, and .March, 1894 ; Bulletin Geol. Society 

 of America, vol. ii, pp. 4«]'>-47n, April, 1891. Ail these articles are accompanied with maps. 



