84 THE ICE AGE IN CANADA. 



Greenland were less elevated, or if there were dry plains 

 around it, the case would be quite different ; as Nares has 

 well shown in the case of Grinnel land, which in the 

 immediate vicinity of Greenland presents very different 

 conditions as to glaciation and climate. 



If the plains were submerged and the arctic current 

 allowed free access to the interior of the continent of 

 America, it is conceivable that the mountainous regions 

 remaining out of the water should be covered with snow 

 and ice, and there is the best evidence that this actually 

 occurred in the glacial period ; but with the plains out of 

 water, there could never have been a sufficiency of snow 

 to cause any general glaciation of the interior. We see 

 evidence of this at the present day in the fact that in 

 unusually cold winters the great precipitation of snow 

 takes place south of Canada, leaving the north compara- 

 tively bare, while as the temperature becomes milder the 

 area of snow deposit moves further to the north. 



The writer has always maintained these conclusions on 

 general geographical grounds, as well as on the evidence 

 afforded by the Pleistocene deposits of Canada, and he 

 continues to regard the supposed evidence of a terminal 

 moraine of the great continental glacier as nothing but 

 the southern limit of the ice-drift of a period of submerg- 

 ence. In such a period the southern margin of an ice- 

 laden sea where its floe-ice and bergs grounded, or where 

 its ice was rapidly melted by warmer water, and where 

 consequently its burden of boulders and other debris was 

 deposited, would necessarily present the aspect of a 

 moraine, which by the long continuance of such conditions 

 might assume gigantic dimensions. Some anomalies in 

 the levels of the so-called terminal moraine are no doubt 

 due to differential elevation. 



