GEOLOGICAL SURVEY OF THE TERRITORIES. 353 



terior margin of the crown. There is no cingulum round the anterior 

 base of the crown. The latter is as long as wide. The inner crest is 

 reduced to a mere angle, and its posterior face is not basin-shaped, but 

 rises to the crest of the inner crescent. The outer face of the latter is 

 sub-horizontal with rising apex, and is concave transversel}". Its ante- 

 rior outer base is narrowed, but is less elevated than the posterior. 



Measurements. 



Meters. 



Length basis crown 0225 



Width basis crown 022 



Width exterior crescent 012 



Depth exterior crescent 02 



This animal was not more than half the bulk of the last; its size was 

 about that of the Tapirtis terrestris. The differences in dentition, which 

 it presents in the possession of a rudimental, anterior external crescent 

 lobe, are so marked, as compared with the last species, as to induce me 

 to believe that it will be found on fuller acquaintance to belong to 

 another genus. This may be called Loxolophodon. Other remains be- 

 longing to this species, or relating to it in size, are contained in Dr. 

 Hayd.en's collection, but cannot now be referred to it with certainty. 



From the Wahsatch beds near Evanston, Utah. 



Especial interest attaches to these fossils from the fact that they be- 

 long to the oldest of the Tertiary periods of North America. Their affin- 

 ities can only be explained in a general way. They represent a family'- 

 distinguished from the type of Titanotherium and Palccosyops^ Leidy, 

 in the presence of only one external crescent lobe of the molars, the 

 place of the other being taken by a tubercle or ridge. The general char- 

 acters are partly perissodactyl and partly ruminant, and not in any 

 great degree suiliine. 



ON THE FOSSIL VERTEBRATES OF THE EARLY TERTIARY FOR- 

 MATION OF WYOMING. 



By Prof. Joseph Leidy. 



The Tertiary formation of the Green River Basin of Wyoming equals, 

 if it does not exceed, in interest that of the Mauvaises terres of White 

 River, Dakota, and that of the Mobrara River, Nebraska. It is evdently 

 older than these, and indeed belongs to another age in succession with 

 them. The Green River Tertiary is probably the equivalent of the Eocene 

 Tertiary ; that of White River, of the Miocene ; and that of the N iobrara, 

 of the Pliocene. 



The first fossil obtained from the Wyoming Tertiary formation was 

 a small herring, from the Green River shales, described in 185G by the 

 writer, under the name of Clupea Immllis. The first crocodik^- irom the 

 vicinity of Fort Bridger was brought to the notice of the writer in 18(38. 

 The ilirst turtle, discovered by Prof. Hayden in thg same locality, 

 and the first mammal, discovered by Dr. J. Van A. Carter, tlie same 

 year, were also described by the writer. Since that time to the present, 

 no less than seventy-one vertebrated animals have been indicated, mainly 

 from collections made during the explorations of Prof, llaydeu in 



23 as 



