276 Description of imrt of Wyoming Territory. 



quiet water. In the gravelly strata rolled fragments of bones are 

 found. 



Nearly all the fossils collected from the Bridger beds have been 

 collected as loose specimens, picked up on the surface of the buttes. 

 No excavations have been made into tlie latter in search of fossils, ex- 

 cept to exhume a jiartially exposed bone, or some parts of a skeleton 

 supposed to be contiguous to specimens lying in view on the surface. 

 Usually only a few pieces of a skeleton have been found together, and 

 in no instance has a complete one been discovered which has been 

 brought to my notice. Generally, too, there has been no certainty that 

 bones or fragments found together belonged to the same skeleton, and 

 in most instances they have appeared to belong to several different 

 animals. 



The remains of vertebrates thus far discovered, in the Bridger Ter- 

 tiary formation, represent all classes, excejDt Batrachians, and these, no 

 doubt, formed members of the ancient fauna ; but their delicate bones 

 have, as yet, escaped detection. 



The remains of mammals are especially numerous, and they belong 

 to many genera, most of which are extinct, and had not been previous- 

 ly described or found elsewhere. The greater proportion of the mam- 

 mals were odd-toed pachyderms, whose nearest living allies are the 

 tapirs. Proboscidian and equine forms appear to have been sparsely 

 represented. Even-toed pachyderms were comparatively few; and 

 ruminants, whose remains are so abundant and varied in the later 

 Tertiary formations east of the Rocky Mountains, appear to have been 

 absent. The other remains of mammals belong to rodents, insectivores, 

 and carnivores, nearly all of extinct genera, not previously described, 

 nor found in other localities. Primates,' bats, marsupials, and eden- 

 tates, ai'e probably represented, but have not been certainly recognized 

 among the fossils which I have had the opportunity of examining. 

 The nature of the formation from which the remains are obtained' is 

 such, that we do not expect to find evidences of the remaining orders 

 of mammals. 



No remains of birds have come under my notice ; but Professor 

 Marsh, who has explored the Bridger Tertiary beds with unusual 

 facilities and great diligence, has reported the discoveiy of specimens 

 which he attributes to half a dozen species of two extinct and pre- 

 viously unknown genera. 



Of reptiles, the remains of turtles are, perhaps, the most abundant 

 fossils met with in the buttes of the Bridger basin. They belong to a 

 number of different genera, several of which are extinct, but other? 

 belong to genera still in existence. Most of them are aquatic forms, 



