Animals Before Mem 



varied from 2 inches in Dinictis to 7 inches in 

 the great Smilodon. 



Toward the close of the Miocene period 

 mastodons made their first appearance in Amer- 

 ica, having probably come into this country 

 from Asia by means of a land connection at the 

 north. 



The Pliocene, however, may be called the 

 age of mastodons, for at this time the race at- 

 tained its maximum, and there were a number 

 of species scattered over the land. They were 

 absent from the Central and Eastern States, 

 save one species. Mastodon obscurus,^ which 

 occupied a strip of territory along the coast 

 from Florida to Maryland. To counterbalance 

 this, they extended into South America as far 

 as Chile and the Argentine RejDublic. These 

 early mastodons were mostly species with very 

 long lower jaws which bore a pair of tusks be- 

 sides the pair present in the skull. It is a 

 pity that none of these four-tusked species sur- 



* Not that the mastodon was obscure, but the valleys between 

 the ridges of the teeth were obscured by little projections, so as 

 not to be so sharply marked as in the more recent species, 



246 



