GLACIATION OF NORTH CENTRAL CANADA l$7 



the Missouri Coteau during this period is uncertain, but there is 

 a strong morainic ridge extending from the Hand Hills north- 

 westward by Sullivan Lake to the Beaver Hills, which may have 

 been formed at this time. A high, stony, lumpy ridge about the 

 same elevation as the Missouri Coteau, and north of and more 

 or less parallel to the Saskatchewan River, between it and the 

 Beaver and Athabasca rivers was doubtless formed a little later 

 in the same glacial epoch. 



Now, confining our attention to the Winnipeg lobe of the 

 Keewatin glacier we find that after reaching its greatest extent 

 in a southeasterly direction it gradually retired northward, and 

 as it retired a portion of the Laurentide glacier which had 

 accumulated in the country farther east, perhaps on the high 

 land of the Labrador peninsula, advanced and the fronts of the 

 two united. The Keewatin glacier had probably retired well 

 north into Manitoba, and possibly beyond the northern confines 

 of that province, before it was joined by the eastern glacier. 

 After they had united the water formed by the melting of the 

 two glaciers was ponded between their fronts and the high land 

 to the south and west, and a large extraglacial lake was formed, 

 which has been called by Mr. Upham Lake Agassiz. 



As the Keewatin glacier retired still farther, the eastern por- 

 tion of the Labradorean glacier continued to advance and oblit- 

 erated most of the marks left by its predecessor, but here and 

 there, on the harder rocks on the east side of Lake Winnipeg 

 and farther north, distinct cross striae were observed, where the 

 later glacier had not rubbed out all the earlier grooves and striae. 

 The later glacier reached to the west side of Lake Winnipeg, 

 or in some places a little beyond, its front assuming a roughly 

 lobate form. Near the mouth of the Saskatchewan River the 

 till formed by both glaciers is well shown, but between the two 

 is a thickness of 12 feet of stratified sand and clay, showing 

 that the Keewatin glacier had retired northward for a suffi- 

 ciently long time before the advent of the Labradorean glacier 

 to allow of the deposition of this thickness of water-lain lake- 

 deposits. 



