(Slacial and Oreglacial 3lafces, 227 



imagination to understand how numerous 

 lakes, much larger than any at the present day, 

 may have extended over large portions of the 

 West and Northwest during the period that 

 the ice was receding. The ice did not stand 

 with an even thickness over the surface of the 

 glaciated area, but at some points it moved 

 down in great lobes, which marked the lines of 

 greatest pressure as well as the greatest ac- 

 cumulation. As the ice melted away, the 

 thick bodies of ice might be many, many years 

 in melting, and they might block the outlet to 

 a very extensive drainage area and thus form 

 a great inland sea from the vast amounts of 

 water that would come from the melting ice. 



All of the region about Winnipeg, in the 

 Red River country, covering great areas of 

 hundreds of miles in extent, is a level plain 

 only lacking the coloring to give to one pass- 

 ing through it the effect of a great unruffled 

 sea. There is no doubt but that all of this 

 region was the bottom of a great lake at some 

 period when the ice was receding. And this 

 accounts for the great depth of black soil that 

 we find in this and other regions. The soil 

 was a water deposit, such as may be found in 

 the bottom of any shallow lake or pond to-day, 

 and thus many thousand years ago provision 

 was made for the fertile areas which to-day 

 are feeding the world with wheat. 



We can imagine that during this period the 



