8 THE ICE AGE IN CANADA. 



America, would bear testimony to the existing difference 

 of climate. The geologist appeals to the same kind of 

 evidence with reference to the climate of the later 

 tertiary period, and let us enquire what is its testimony. 



" The first and most general answer is that the pleisto- 

 cene climate was colder than the modern. The proof of 

 this in western Europe is very strong. The marine 

 fossils of this period in Britain are more like the existing 

 fauna of Norway or of Labrador than the present fauna 

 of Britain. Great evidences exist of driftage of boulders 

 by ice, and traces of glaciers on the higher hills. In 

 North America the proofs of a rigorous climate, and 

 especially of the transport of boulders and other materials 

 by ice, are equally good, and the marine fauna all over 

 Canada and New England is of boreal type. 



" Admitting, however, that a rigorous climate prevailed 

 in the pleistocene period, it by no means follows that the 

 change has been equally great in different localities. On 

 the contrary, while a great and marked revolution has 

 occurred in Europe, the evidences of such change are very 

 much more slight in America. In short, the causes of 

 the coldness of the pleistocene seas to some extent still 

 remain in America, while they have disappeared or have 

 been modified in Europe. 



" If we inquire as to these causes as at present existing, 

 we find them in the distribution of ocean currents, and 

 especially in the great warm current of the gulf stream, 

 thrown across from America to Europe, and in the arctic 

 currents bathing the coasts of America. In connection 

 with these we have the prevailing westerly winds of the 

 temperate zone, and the great extent of land and shallow 

 seas in northern America. Some of these causes are 

 absolutely constant. Of this kind is the distribution of 



