MOOSE DEER 33 



necessity. This problem of the Bering Strait land bridge, 

 however, will be more fully discussed later on (pp. 83 86). 



The moose, or elk as it is called in Europe, has been stated 

 to occur in the Caucasus, but its range only extends to the 

 forests north of this mountain range. Like the reindeer, it 

 occurred much further south formerly, even as far as 

 northern Italy, and yet no theories as to a former arctic 

 climate are founded on this fact. In Caesar's time the elk was 

 still abundant in the Black Forest in southern Germany, 

 while it is now confined to certain parts of Russia and 

 Scandinavia. 



Many other American species resemble the moose in their 

 range, except that they manifest more clearly their Asiatic 

 origin. The further west we travel the more often do we 

 meet with such types of animals. 



We have now become acquainted with species that seem 

 to be of arctic American or Greenland origin. A few 

 apparently travelled across from Europe. Others were partly 

 of southern extraction having advanced northward from the 

 United States, and partly derived from a western invasion of 

 the continent. What we want to find out ne-xt is the geological 

 age of some of these invasions into boreal America. The 

 writings on this subject of the prominent biological authors 

 are largely biassed by the prevalent geological opinions with 

 regard to the nature of the Ice Age. 



It is currently believed that a climatic change towards the 

 end of the Pliocene Period caused ice-masses to form in 

 various Canadian centres, so as to produce continental 

 glaciers of the type of the ice-sheet now covering Greenland. 

 These glaciers are supposed to have spread from at least three 

 centres in Canada, termed the Labradorean, Keewatin, and 

 Cordilleran. During this time, viz., in our most recent 

 geological age, the " Pleistocene Period," fully one half of 

 North America is thus assumed to have been gradually buried 

 beneath these vast sheets of ice. Ice is believed to have ex- 

 tended practically all over the continent from Newfoundland 

 in the east to Vancouver in the west, and from the Arctic 

 Ocean to the present site of the City of St. Louis.* Belying 



* Russell, I. 0., " North America," p. 315. 

 L.A. D 



