278 



THE CANADIAN NATURALIST. 



[Vol. X. 



The following table shows a classification of the geological 

 epochs newer than the Pliocene Tertiary in America, represented 

 in descending order : 



VII. THE TILL, ERIE AND OTHER CLAYS. 



General Distribution of the Erie and Saugeen Cloys. — The 

 greater portion of the surfaces of the striated rocks of Ontario is 

 covered by Erie clay. This clay is always stratified, sometimes 

 with sandy partings, and is more or less calcareous. It is blue 

 when wet, but of an ash-color wheu dry, and the upper portion 

 is of very fine texture. It frequently contains rounded boulders, 

 and according to Dr. Robert Bell, the lower portion includes a 

 greater or smaller number of fragments which are angular when 

 compo.sed of palaeozoic rocks. It contains no shells of marine 

 origin. Some of the immediately overlying and closely a^isoci- 

 ated deposits are known to contain a considerable fauna of fresh 

 water .shells. The Erie clay has been seen at various heights 



