118 



THE ICE AGE IN CANADA. 



slope (amounting, as has 

 been shown, to over four 

 feet per mile) to the first 

 transverse watershed and 

 plateau of the Lignite 

 Tertiary. Such an ice- 

 sheet, moving through- 

 out on broad plains of 

 soft, unconsolidated Cre- 

 taceous and Tertiary 

 rocks, would be expected 

 to mark the surface with 

 broad flutings parallel to 

 its direction, and to ob- 

 literate the transverse 

 watersheds and valleys. 



" If it be supposed that 

 a huge glacier, resting 

 on the Laurentian axis, 

 spread westward across 

 the plains, the physical 

 difficulties are even more 

 serious. The ice movinj? 

 southward, after having 

 descended into the Eed- 

 Eiver trough, would have 

 had to ascend the eastern 

 escarpment of soft Cre- 

 taceous rocks forming its 

 western side, which in 

 one place rises over 900 

 feet above it. Haviner 



the second prairie-steppe, it would have had to 



