ESKEES IX MANITOBA. 183 



ice surface sloped toward the southeast. On the east drift limestone is 

 absent or very rare, because no limestone formations were crossed within 

 several hundred miles by that part of the ice-sheet; but on the west the 

 drift, consisting" chiefly of a thick sheet of till, contains much fine limestone 

 detritus, sand and gravel, and frequent bowlders of limestone, bonie south- 

 eastward from Manitoba over the Archean area of the southwest pai't of 

 the Lake of the Woods, of Rainy River, and of northern and central Min- 

 nesota. In the same directions with the slopes of the ice surface, which 

 are known from the courses of the glacial striae and the transportation of 

 the drift, the streams of the glacial melting flowed convergently from the 

 east and west, from the ice over northern Minnesota and eastern Manitoba 

 on one side, and from that over the Red River Valley and western Mani- 

 toba on the other, toward this belt of plentiful superficial deposits of gravel 

 and sand. 



Dr. George M. Dawson^ and Dr. A. C. Lawson^ have referred these 

 gravel and sand beds, observed by them only about the south part of the 

 Lake of the Woods and along Rainy River to the mouth of Rainy Lake, 

 within the area of Lake Agassiz, to lacustrine action. That explanation, 

 however, is inconsistent with the restriction of the deposits to a small part 

 of the area of this glacial lak(^, and with their continuation far to the south, 

 beyond the limit of the lake and iipon a district that rises in part consider- 

 ably above it; while their distribution and character show that instead 

 they were derived, as indicated, directly from the ice-sheet and its inclosed 

 drift. They will be again noticed in connection with the history of the . 

 formation of Lake Agassiz, to be considered in the next chapter. 



BIRDS HILL AND OTHER ESEERS IN MANITOBA. 



Prominent eskers begin at Birds Hill, the first station of the Canadian 

 Pacific Railway northeast of Winnipeg, from which it is 7 miles distant, and 

 extend thence 7 or 8 miles east-northeast and an equal distance southeast, 

 as shown in the sketch map forming fig. 9. The southern and southeastern 

 portion of this group comprises many low ridges of gravel and sand 5 



' Report on the C4eology and Resources of the Region iu the Vicinity of the Forty-ninth Parallel, 

 pp. 203-218. 



-Oeol. and Xat. Hist. Survey of Canada, Annual Report, new series, Vol. I, for 1885, pp. 131 and 139 

 CC ; Vol. III. for 1887. pp. 171-176 F. 



