310 R. BELL — GLACIAL PHENOMENA IN CANADA. 



Bea, due to a slight shifting of the centre of gravity of the earth on account 

 of the accumulation around the south pole of the mass of ice, a mile thick 

 and 2,000 miles in diameter, which is believed to exist there. In the north- 

 ern portions of America, along with this general movement, local elevations 

 ami depressions may also he going on. Bui the evidence of the numerous 

 Arctic voyagers who have visited nearly all parts of the northern regions of 

 the Dominion shows that this movement is taking place with apparent 

 uniformity throughout this large area of the earth's surface. 



Towards the close of' the period of depression following the glacial era, the 

 northern parts of lakes Huron and Superior must have heen relatively lower 

 than the southern in order to account for the well-marked terraces and 

 beaches which we find at various elevations up to more than 300 feet above 

 the levels of their present outlets, as there is no evidence of harriers of any 

 kind having existed in their neighborhoods in such recent times. The Dav- 

 enport ridge behind Toronto, and gravel ridges at the head of Lake Ontario, 

 prove that its waters stood at least 17<> feet higher than now at some time 

 since the glacial period; and, as there are no remains of a harrier at its east 

 end, it is probable that the bed of the St. Lawrence below it was so elevated 

 as to keep hack the waters to this additional depth. The evidence thus 

 afforded by some of the great lakes of the St. Lawrence goes to confirm the 

 theory of a former depression and subsequent elevation of the continent 

 towards the north and east. 



