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 role in the Eocene and Paleocene of North America and 



Fig. 134. — White River ftitanothcre (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 jPterodon, 

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

 the Northwest Territory of Canada; the other, '\Hycenodon, 

 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 



