286 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



The Puerco fauna was much like that of the Torre j on, but 

 even less advanced and diversified. The herbivorous marsu- 

 pials were more abundant, and some of them {^Polymastodon) 

 larger than those of the Torrejon ; Insectivora may have 

 been present, but this is doubtful. The fcreodonts, so far 

 as they have been discovered, were less numerous, varied and 

 specialized than those of the Torrejon and included but one 



Fig. 144. — Head of an fallotherian marsupial {tPolymastodon taoensis) from the 

 Puerco stage. Restored from a skull in the American Museum of Natural 

 History. 



of the families which passed over into the Eocene. The 

 fCondylarthra were much less common and the fAmblypoda 

 but doubtfully represented, but the edentate-like fTseniodontia 

 were conspicuous. 



Not only were the Paleocene faunas radically different 

 from the mammals of our time, but they could not have been 

 ancestral to the latter, being hardly more than an advanced 

 and diversified Mesozoic assemblage. It is true that some 

 of its elements, such as the fCondylarthra, fAmblypoda and 

 fCreodonta, developed greatly and played an important part 



