FAUNISTIC AFFINITIES 25 



is largely composed of Siberian immigrants. It is possible that 

 these only began to enter North America firom the extreme 

 west at the time when Labrador was already joined to Green- 

 land. Moreover, we may assume that as soon as the North 

 Atlantic land connection excluded the Gulf Stream from the 

 Arctic Ocean, glaciers began to gather on all the mountain 

 ranges surrounding the northern parts of the ocean, thus 

 preventing many forms of animal life from taking advantage 

 of the facilities afforded by the land bridge of passing from the 

 one continent to the other. The greater warmth on the 

 northern coasts led to greater evaporation of sea water and 

 more ample condensation of moisture on the elevated lands 

 surrounding the ocean. All this will be more fully discussed 

 in the succeeding chapters. 



Apart from the authorities already cited who expressed 

 thejmselves in Eavour of a north Atlantic land connection, 

 beitween northern Europe and North America, Professor 

 Lobley,* Dr. Brown,t Mr. Grant J and Mr. Krishtafovitch § 

 have all urged the same view on different grounds. 



* Lobley, J. L., " American Fauna and its Origin," p. 26. 



t Brown, A. E., " American Big Game," p. 87. 



I Grant, M., " Mammals of North America," p. 12. 



§ Krishtafovitch, N. J., "La derniere periode glaciaire," p. 296. 



