Tertiary Fossils of Canada, Sfc, 197 



period in Britain are more like the existing fauna of Norway or 

 of Labrador tlian 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. In evidence of these facts 

 I may appeal to the papers and other publications of Sir C. LyeU 

 and Professor Ramsay on the formations of the so called glacial 

 period in Europe and America,* and to my own previous papers 

 on the tertiaries of Canada. 



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 evi- 

 dences 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 must have dis- 

 appeared or been modified in Europe. 



If we enquire as io these causes as at present existing, we find 

 them in the distribution of ocean currents, and especially ;n the 

 great warm current of the gulf stream, thrown across from Ame- 

 rica to Europe, and in the Arctic currents bathing the coasts of 

 America. In connection with these we have the prevailing wes- 

 terly 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 the winds 

 depending on the earth's temperature and rotation. The courses 

 of the currents are also constant, except in so iar as modified by 

 coasts and banks; and the direction of the drift-scratches and 

 transport of boulders in the pleistocene both of Europe and Ame- 

 rica, show that the arctic currents at least have remained un- 

 changed. But the distribution of land and water is a variable 

 element, since we know that in the period in question nearly all 

 northern Europe, Asia and America were at one time or another 

 under the waters of the sea, and it is consequently to this cause 

 that we must mainly look for the changes which have occurred. 



* Lyell's travels in North America, Ramsay on tlie glaciers of Wales, 

 and on the glacial phenomena of Canada. See also Forbes on the fauna 

 and flora in the British Islands, in Memoirs of geological surrey. 



