GEOLOGICAL SURVEY OF THE TEREITOEIES. 559 



Creek, in Wyoming. The crauinm and fore foot and leg were excavated 

 from the deposit. 



Formation, the Bridger Group of the Eocene of Hayden. 



Professor Marsh has described two genera of Garnivora from the same 

 formation, embracing species approaching this one in size. They are 

 both distinguished by the broader forms of the crowns of the inferior 

 molar teeth, and other points. 



STYPOLOPHUS, Cope. 



Proceed. American Philos. Soc. 1872, p." 466 ; published August 3, 1872. 



This genus embraces small species of carnivorous animals found by 

 the writer in the Eocene formation of the Bridger Group. It is repre- 

 sented by portions of mandibular rami of three species, with molar and 

 premolar teeth. 



The generic characters are seen in the composition of these molars, 

 which have but two roots, and a posterior table, as is seen in tubercular 

 molars of some Yiverridce. The anterior two-thirds of the crown is com- 

 posed of conic cusi)s. On the last molars these are in two series, two 

 lower, of the inner, and one more elevated, of the outer, opposite the 

 interval between the inner. Its outer face is regularly convex, but its 

 posterior forms, with that of the outer series, a single flat vertical plane, 

 which forms a sharp angle with the inner and outer faces of the cusps. 



The structure is, in general, somewhat like that of llesonyx, Cope, but 

 the lack of cutting edge on the posterior lobe, and the two rows of tuber- 

 cles seiDarate it widely. Dr. Leidy describes Sinopa as having a sec- 

 torial tooth as in ordinary Garnivora, with an interior cusp ; hence it is 

 not probably the present form, although one species was about the size 

 of the 8. raj^ax. 



STYPOLOPHUS INSECTIVOEUS, CopC. 



Proceed. A^er. Philos. Soc. 1872, p. 469 ; published August 7, 1872. 



Eepresented by a posterior molar and a premolar of the right side of 

 an animal less than half the size of the >S'. pungens, Cope. The molar 

 presents three anterior trihedral acute tubercles, of which one is exte- 

 rior and more elevated than the others. Its posterior plane forms one 

 transverse face with that of the inner posterior. The posterior tuber- 

 cular heel is low, and supports an oblique ridge which bounds a deep 

 groove behind the outer cusp, no doubt to receive that of the upper jaw. 

 This arrangement is not seen in ;S'. pungens. The premolar is a fiat cone 

 with faint traces of a tubercle behind and ciugulum on inner side. 



Measurements. 



M. 



Length crown molar 0. 0050 



Height inner cusp 0040 



Length heel 0025 



Width crown 0030 



Height crown premolar 0040 



Length crown premolar 0040 



Found in the Eocene Bad Lands of Black's Fork, by the writer. 



STYPOLOPHUS PUNGENS, Cope. 

 Loc. cit., 1872, p. 466 ; published August 3. 



This is the type of the genus, and is partially described in the 

 generic paragraph. 

 The enamel is smooth. 



