Tlie Life of Yesterday 



found from our Southern States far into the 

 North and West. Side by side with this species 

 in our Southern States was his smaller brother, 

 Equus fraternus, while Texas, Oregon, and 

 other sections of the country had their local 

 and characteristic species, just as to-day differ- 

 ent parts of Africa hav^e their different species 

 of zebras. 



The last land connection between Asia and 

 North America, across Bering Strait, let in the 

 mammoth, and at his heels came the ancestors 

 of the great brown bears of Alaska, the moun- 

 tain sheep and mountain goat, and of the bison ; 

 for the groups to which these animals belong 

 had their origin in the Old World, and did not, 

 like the llamas and great ground sloths, develop 

 on this continent. The grizzly bear was an 

 earlier inhabitant and lived with the horse and 

 llama in the late Pliocene, and the black bears 

 are probably natives of this continent, although 

 we do not as yet know their line of descent. 

 At the time the mammoth was coming east- 

 ward it is not improbable that the horse passed 

 westward into Asia, for its bones are numerous 



259 



