SUCCESSIVE MAMMALIAN FAUNAS 253 



There was quite a variety of Insectivora ; some were survivals 

 of a family that was abundant in the Eocene, others, like the 

 hedgehogs, moles and shrews, were probably immigrants. 

 Here we find the last of a group (order or suborder) of ancient 

 and primitive flesh-eaters, the fCreodonta, that had played a 

 great r61e in the Eocene and Paleocene of North America and 



Fig. 134. — White River ftitanothere (iTitanotherium robustum) reduced to the same 



scale as Fig. 133. 



Europe. In White River times but a single family (fHyaeno- 

 dontidse), with two genera, remained of the Eocene host. One 

 of these genera (^Hemipsalodon), a very large beast of prey, 

 which was almost identical with the Old World genus ]Pterodon, 

 was confined to the lower substage of the White River beds in 

 the Northwest Territory of Canada; the other, ^Hyaenodon, 

 which was also an Old World form, was represented abundantly 

 in the United States by many species. In size, these species 

 ranged from a small fox to a large wolf, but they all had dis- 

 proportionately large heads, and small, weak feet, with blunt 

 claws, so that they must have been very curious-looking 

 creatures and were probably carrion-feeders rather than active 

 catchers of prey. The White River members of the family 



