93 



tion of all the lobes approaching the base of the crown. The transverse 

 diameter of the latter is J of an inch; its fore and aft diameter externally ^ 

 of an inch. 



HiPPOSYUS ROBUSTIOR. 



A lower-jaw fragment containing a single tooth, obtained by Professor 

 Hayden on Henry's Fork of Green River, apparently indicates a more robust 

 ■species of the same genus as the former. I at first attributed the specimen 

 to a species of Notharctus, with the name of JV. rohustior, but a comparison 

 of the tooth, represented in Fig. 40, Plate VI, with those o'i Hipposyus fonno- 

 sus, Figs. 38, 39, will at once suggest the probability of its pertaining to a 

 larger species of the latter genus. Perhaps' the specimen may belong to a 

 more robust individual of the same species. 



The jaw-fragment is too imperfect to ascertain anything in regard to its 

 anatomical characters other than its thickness. Below the second molar it is 

 J of an inch thick; in the specimens attributed to H. formosus it ranges in the 

 same position from 34^ to 3J lines in thickness. The second molar tooth is 

 3i lines broad and 2^ lines wide. 



Order Prohoscidea ? 



Large quadrupeds with fivettoes to the feet ; molar teeth with transverse 

 ridges; femur without a third trochanter; nose prolonged into a cylindrical 

 trunk or proboscis. 



UINTATHERIUM. 



While encamped in Dry Creek Cafion, forty miles to the east of Fort 

 Bridger, Drs. Carter and Corson spent a day in traversing a most desolate 

 region to some buttes about ten miles farther to the east. They returned to 

 camp after sundown laden with fossils, among which were the remains of the 

 largest animal which had yet been brought to our notice from the Bridger 

 Tertiary beds. '^J^hese remains consist of the cranial portion of a skull with 

 fragments of both jaws attached to the same matrix, a nearly complete arm- 

 bone, and fragments of other limb-bones. A notice of these remains, attrib- 

 uted to a pachyderm with the name of Uintathcrium rohustum, was com- 

 municated in a letter to the Academy of Natural Sciences of Philadelphia, 

 and was published August 1, 1872. 



On the jJrevious day to the discovery of the remains of Uintatherium, 

 while engaged in the search for fossils along the buttes, al)ou( a mile to the 



