134 NEW YORK ZOOLOGICAL SOCIETY. 



of the American bison, which migrated in summer as far north 

 as the Saskatchewan and southw^ard in winter to the Alexican 

 border, suggests that it is quite possible that these animals did 

 not habitually spend the winter in Alaska, but on the approach 

 of the cold season migrated southward to warmer climates, or 

 crossed into Siberia on the former land connection over what are 

 now Bering Straits. If this hypothesis be correct, the climate of 

 Alaska during the Pleistocene and recent periods, may not have 

 radically differed from the climate of to-day. 



The extension of placer mining in Alaska, when conducted in 

 a more systematic manner than at present, will undoubtedly bring 

 to light other forms of large mammals, most probably types re- 

 lated to those already mentioned, together with the remains of 

 carnivorous types. 



