FAUNISTIC AFFINITIES 
25 
is largely composed of Siberian immigrants. It is possible that 
these only began to enter North America from 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 
themselves in favour of a north Atlantic land connection, 
between northern Europe and North America, Professor 
Lobley,* * * § Dr. Brown,f Mr. Grant $ 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. 
X Grant, M., “ Mammals of North America,” p. 12. 
§ Krishtafovitch, N. J., “La derniere periodo glaciaire,” p. 296. 
