162 THE WASATCH AND BUIDGER FAUNiB. 



tinct keel. Both have a slight median elevation in the short diameter. The 

 fossae are rather far apart; edges smooth. Length of the larger "".085: 

 width .045. 



There are traces of the sutures of the neural arches of the lumbar verte- 

 brae, showing that the individual was adult, but not aged, at the time of 

 death 



The only species with which the present one can be confused, is the 

 C. aptus Leidy, which was founded on a cervical vertebra from South Bitter 

 Creek, "Wyoming. In that locality the beds of the Wasatch and Green 

 River formation occur, and probably the Bridger; those of the Washakie 

 group are not mauA', perhaps fifteen miles distant. This vertebra belongs, 

 according to Leidy, to the cervical series of an adult animal, and measures 

 only 16 lines long. A vertebra of the C. clavis, which must coiTespond in 

 position very nearly with the one described by Leidy, measures 27 lines in 

 length, and is therefore between half as long again and twice as long. This 

 indicates an animal of so much greater size as to render their specific iden- 

 tity highly improbable. A crocodile occurs in the Washakie beds with the 

 C. clavis, of which I possess a fragmentary skull. It is of a size appropriate 

 to the vertebra typical of C. aptus. 



Crocodilus affinis Marsh. 



American Jouraal of Science and Arte, 1871, June. 

 Plate XXI, figs. 1-3. 



This is the most abundant species of tlie beds of the Bridger basin. I 

 took a nearly complete cranium with some vertebrae from a bad land bluft' 

 on Smith's Fork of Green River; and my friend George Wilson, of Chey- 

 enne, Wyoming, presented me with a considerable part of the skeletons of 

 two individuals, including two nearly complete skulls from the Church 

 Buttes. Fragments of others were found by various members of my party 

 on Black's and Ham's Forks of Green River. 



I have pointed out the characters which distinguish this species from 

 the C. clavis. Under the description of C. elliotii, Dr. Leidy loc. cit., has 

 given a pretty full description of another near ally, so far as his material 

 permitted. 



One readily observes that the frontal and j)arietul regions of the skulls 



