GEOLOGICAL SURVEY OF THE TERRITORIES. 607 



space beliiud the interval between the i)osterior tubercles and gives 

 origin to a cingulum which passes round the bases of the outer tubercles. 

 It extends round the front of the tooth to the outer anterior tubercle. 

 Wear would produce small angular crescents from the two posterior and 

 tlie outer anterior tubercle. Greatest length of crown, M. 0.008 ; width, 

 .006. The enamel of the tubercles is rugose. 



This ungulate was of about the size of the L. sylvatictmi, or equal to 

 the raccoon. It differs considerably from that species in the less isola- 

 tion of the tubercles of the molar, and the crescentic form of the inner 

 posterior. 



From Green Eiver beds near Evanston, and the same near Black 

 Buttes, Wyoming, on opposite sides of the Bridger Basin. 



Orotherium stlvaticum, Leidy. 



Lophioilierium sylvaticum, Leidy. Proceedings Acedemy Natural ScieDces, Philadelphia, 

 126; Orotherium, Marsh, American Journal Science and Arts, 1872, August 13. 



From Black's Fork, Wyoming. 



OLIGOTOMUS, Cope. 



On some Eocene Mammals, &c., March 8, 1873, p. 2. 



Char. gen. — Molars constructed much as in Syopsodus and LopJiiothe- 

 rium, viz, with two external subtrihedal cusps, which wear into cres- 

 cents, the posterior connected by a low oblique ridge with the basis of 

 the anterior cone of the inner side ; the latter with two conic cusps. It 

 differs from these genera and Orotherium in the possession of but two 

 premolars ; the inferior molars are probably six, leaving four true 

 molars. 



Oligotomus cinctus, Cope. 



Loc. cit. 



• Char, specif. — In thivS animal the cusps of the molars are elevated, the 

 external most so, the anterior being somewhat bilobate. Premolars with 

 two fangs. There is a rudimental posterior tubercle in M. 1 and 2, and ~ 

 a strong cingulum round the outer side' of the crown. In an adult with 

 worn teeth the enamel is obscurely rugose. 



Measurements. 



M. 



Length of five molars 0. 0326 



Length of two premolars 0120 



Length of M. 2 0067 



Width of M. 2 anteriorly 0050 



Width of M. 2 posteriorly 0050 



Depth ramus at front of P. M. 1 0126 



From Cottonwood Creek, Wyoming. 



ANTIACODOK, Marsh. 

 American Journal Science and Arts, 1872, p. 210. 



Antiacodon pygm^us. Cope. 



Zophiotherium pygmceum, Cope. Proceedings American Philosophical Society, 1872, 

 extras, July 20 ; Antiacodon vemistiis, Marsh, American Journal Science and Arts, 1872, 

 (XJublished August 13.) Ryojysodus jyi/gmwus, Cope, loc. cit., p. 461. 



From Cottonwood, Wyoming. 



Eepresented by a portion of the right mandibular ramus, with the 

 penultimate and anteDenultimate molars in perfect preservation. These 



