Peterson: Material Discovered in Uinta Basin. 51 



Locality: Six miles east of^Myton, Uinta County, Utah. 



Horizon: Uinta Eocene, Horizon C, near base. 



Specific Characters: Antero-posterior diameter of P^ and ilfy subequal. 

 P-^ with anterior basal cusp; absence of posterior accessory cusp, hut a 

 cutting heel of considerable size present. Mj with broad and high 

 trigonid; small heel, not basin-shaped. M^ of proportionally small 

 size, trigonid low, and heel small. M-^ one-rooted. Animals larger 

 than Prodaphxnus scotti. 



This specimen appears to differ both from Miacis and Uintacyon'' 

 and may represent a new genus, nevertheless it is thought best to 

 provisionally place it in Prodaphcenus having regard to the incom- 

 pleteness of the type. The unfortunate absence of the upper teeth 

 prevents comparison with Prodaphcenus scotti. It is purposely kept 

 sepacate from the latter on account of its greater size and also to save 

 a possible confusion later on, since it may not even pertain to the 

 same genus. The description and measurements of '^Miacis'' 

 vulpinus Scott and Osborn^ do not appear to agree with the present 

 specii-ticn. The structure of the lower jaw and the teeth do not com- 

 pare well with Procynodictis vulpiceps Wortman and Matthew.^ 



The general contour of the mandible is perhaps more like Uintacyon 

 than Miacis. It is certainly heavier, deeper, and I should judge^" 

 relatively shorter than Prodaphcenus (Miacis) uintensis (Osborn) 

 the symphysis being especially heavy. The canine, as indicated by 

 the root, is heavy and laterally compressed. Py is single-rooted, Po- 

 is two-rooted, but, as in Procynodictis, apparently of considerably 

 smaller size than P-jj. Py suggests that of Miacis hargeri; it is a large 

 tooth with a prominent anterior basal tubercle, a slight and rather 

 smooth cingulum externally, entirely smooth internally, and a large 

 cutting heel. My has a high and broad trigonid with the anterior 

 tubercle well developed, as in Procynodictis vulpiceps and later forms. 

 The heel is rather slightly developed both antero-posteriorly and 

 transversely. It is of a trenchant type with a moderately heavy 

 cingulum, extending along the inner face to the base of the postero- 

 internal tubercle of the trigonid. The antero-posterior diameter of 



^ Dr. W. D. Matthew, Mem. Amer. Mus. Nat. Hist., Vol. IX, 1909, pp. 326-377. 



« Proc. Amer. Philos. Soc, Vol. XXIV, 1887, p. 255. 



^ Bull. Amer. Mus. Nat. Hist., Vol. XIV, 1899, p. 121. 



1" No contact has been established between the anterior and posterior portions 

 of the mandible, but there would appear to be little doubt that the two pieces 

 pertain to the same individual. 



