THE CONTINENTAL ICE-SHEET. HI 



Including this Canadian part of the southern limit of the Wisconsin 

 stage of the ice-sheet, its course at the begiinuing of its time of formation 

 of the series of mai'g-inal moraines, several of which were formed contem- 

 poraneously with the existence of Lake Agassiz, may be briefly noted as 

 follows: From Nantucket, Marthas Vineyard, Block Island, and Long Island 

 it runs west-northwestward across northern New Jersey and northeastern 

 Pennsylvania, to an angle near Salamanca, N. Y., about 50 miles south of 

 Buffalo and the eastern end of Lake Erie; thence it passes southwestward 

 into southern Ohio ; thence west-northwestward and northward in numerous 

 loops through Indiana, northeastern Illinois, and Wisconsin, to an angle 

 less than 75 miles southeast of the western end of Lake Superior; thence 

 southward to Des Moines, Iowa; thence north-northwestward to the head 

 of the Coteau des Prairies; again southward to the Missouri River and the 

 northeastern edge of Nebraska; thence northwestward, very irregularly 

 lobate, througli South Dakota and North Dakota, to Wood Mountain, in 

 the southern edge of Assiniboia; thence westward by the Cyj^ress Hills 

 to the Rocky Mountains on the international boundarj-; and thence, in 

 lobes determined Ija' the mountainous character of the country, across 

 northwestern Montana, the narrow northern extremity of Idaho, and the 

 northeastern edge and the central and western parts of Washington, to 

 the Pacific coast on the latitude of 48°, Puget Sound and the Strait of 

 Juan de Fuca being wholly inside the glaciated area. 



Along the shores of British Columbia and southern Alaska the ice- 

 sheet pushed through gaps of the Coast Range and terminated in the sea 

 from the Strait of Juan de Fuca and Vancouver Island northwestward to 

 the vicinity of the Copper River and Prince Williams Sound.^ But most 

 of Alaska and a portion of the adjacent Northwest Territory of Canada 

 had too little snowfall or were otherwise aff'ected b}' climatic conditions 

 unfavorable for glaciation. The northwestern limit of the continental 

 ice-sheet, as determined by Russell,^ McConnell,^ and Dawson,* passes 



'G. M. Dawson, In Quart. Jour. Geol. Soc, London, Vol. XXXVII, 1881, p. 278; Trans., Roy. Soc.of 

 Canada, Vol. VIII, sec. 4, 1890, PI. II 



= Bulletin, G. S. A.. Vol. I, up. UO, 146-148. 



'Ibid., p. 544. 



<Geol. and Nat. Hist. Survey of Canada, Annual Report, new series. Vol. III. for 1887-88, pp. 132 B 

 and 149 B. 



