66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



seems large enough to be included in this species. Matthew in 191 5 

 (b, p. 326) noted only three specimens of H. walcottianus, including 

 the type in the collection from the Lost Cabin beds of the Wind 

 River Basin and two from this horizon in the Bighorn Basin. 



PHENACODONTIDAE 

 PHENACODUS PRIMAEVUS Cope 



The absence of Phenacodus in the abundantly represented La Barge 

 fauna of the Knight was earlier (1952) noted, although the type of 

 P. primaevus is from a somewhat earlier horizon along Bear River 

 near Evanston. A well-worn P4 and lower molar (U.S.N.M. No. 

 22668), evidently associated, from the Bitter Creek locality compare 

 very closely in size with Gray Bull materials referred to Phenacodus 

 primaevus. The lower molar is worn so that its pattern is poorly 

 revealed. The premolar, however, is clearly of Phenacodus and can 

 be matched in detail with this tooth in P. primaevus, although the 

 posterointernal angle or entoconid portion is broken away. 



The lower jaw of Phenacodus described in 1952 (p. 61) as coming 

 from beneath the variegated deposits of the Knight about 3 miles east 

 of Fossil Station is now known to be from the Evanston formation 

 (Gazin, 1956b). 



PHENACODUS, cf. VORTMANI (Cope) 

 (Plate 9, figures 8 and 9) 



A maxilla with P^-M^ and a lower jaw with P3-M3, together with 

 other tooth portions belonging to the same individual, representing a 

 small species of Phenacodus, were found at a locality to the south- 

 west of Elk Mountain in the Fossil Basin. It is not certain, however, 

 that the horizon represented is as low as the Gray Bull level at the 

 base of the escarpment due west of Elk Mountain. The localities 

 are a couple of miles apart. 



The size of the species represented is comparable to Phenacodus 

 vortmani, or possibly to P. copei. The details of P3 and P4 cor- 

 respond more closely to the description given by Granger (1915, 

 p. 343) for P. vortmani, although the horizon represented by the 

 Fossil Basin specimen is in all probability not as late as that for the 

 type. It should be noted, however, that Granger recognized P. vort- 

 mani in all three levels of Wasatchian time, 



PHENACODUS, cf. BRACHYPTERNUS Cope 

 A single upper molar in the collection from the Red Desert locality 

 east of Steamboat Mountain is about the size of an M^ in Ectocion 



