NATURAL HISTORY, TORONTO REGION 



Above this sheet of boulder clay resting on the 

 eroded surface of the delta there are three other 

 layers of till with stratified sand or clay between, the 

 whole reaching a thickness of two hundred feet. 

 None of the upper interglacial beds seem of much 

 importance compared with the earliest, the Toronto 

 Formation. 



At certain sand pits in western Toronto near 

 Christie and Shaw Streets, a little north of Bloor 

 Street, there are interglacial deposits of a quite dif- 

 ferent character, cross-bedded sand and gravel laid 

 down by powerful currents. In these beds bones 

 of bison, Cervalces borealis, and of mammoth or 

 mastodon have been found, as well as ivory and a 

 few shells. The relations of these sands to the other 

 beds are uncertain, but they are undoubtedly inter- 

 glacial. 



Interglacial beds have been found at the Whirl- 

 pool, Niagara, near Dundas, at the head of Lake 

 Ontario, and at some other points; but few or no 

 fossils have been obtained from them, and it is not 

 known whether they should be correlated with the 

 Toronto Formation or not. There is some reason Ifc 

 believe that the Aftonian interglacial beds of Iowa, 

 which have yielded Cervalces, as well as a number 

 of other mammals, may be of the same age a? the 

 Toronto Formation. 



GLACIAL LAKES. 



Each advance of the ice must have ponded back 



the water before it in the present lake basins, but 



72 



