14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



and nearby ridges in the vicinity of Fossil Station on the Oregon 

 Short Line branch of the Union Pacific Railroad. A number of 

 specimens of fossil mammals have been found in the variegated 

 Knight beds beneath the Green River beds around Fossil Butte and 

 adjacent areas. It is here that specimens first found by Princeton 

 University parties in 1939 and 1940 were reported by me in 1952. 

 Smithsonian Institution parties obtained a number of specimens from 

 west-facing exposures in the saddle to the north of Fossil Butte as 

 well as on the more accessible slopes around the south side of the 

 butte. 



I am not certain that the remains collected on the slopes of Fossil 

 Butte all represent the same division of Wasatchian time. Heptodon 

 has been found only high on the slopes in the somewhat darker red 

 beds close beneath the Green River shales. Also, the tooth portions 

 of Dldymictis considered to represent D. altidens were from a high 

 level. It is clear that these upper slopes are later than Gray Bull and 

 the presence there of Hyopsodus browni would suggest Lysite — but 

 finding this species or a form within the same size range in the 

 Dad fauna, in association with Lamb d other ium, somewhat weakens 

 this particular evidence. The absence of Meniscotheriwn, so abun- 

 dant in the nearby La Barge localities, had been thought significant 

 but the more recent finding of a maxilla in the saddle to the north 

 of Fossil Butte and a lower jaw portion on the east side would 

 appear to rule out this evidence also; however, the species repre- 

 sented may not be t3rpical M. robustum because of the comparatively 

 small size of the teeth. Nevertheless, the absence of Lambdotherium, 

 invariably found in beds just below the Tipton tongue of the Green 

 River beds belonging to Lake Gosiute, lends tentative support to a 

 Lysitean age assignment. The remaining forms represented on the 

 higher slopes of the butte, i.e., Pelycodus, near P. jarrovii; Ecto- 

 ganus, sp. ; Reithroparamys sp. ; Sinopa, cf . midticuspis ; cf . Vidpaviis 

 australis; Hyopsodus, cf. miticulns; Hyracotherimn; and Hexacodits 

 uintensis apparently do not furnish critical information. It may be 

 further noted, however, that the species of Hexacodus cited is not 

 the same as that in the La Barge fauna. 



While there does not appear to be any certain evidence to demon- 

 strate that the lower part of Fossil Butte is older than Lysite, it 

 should be noted that Coryphodon seems much more abundant on the 

 middle and lower slopes, much as it is to the west of Elk Mountain 

 and at Bitter Creek. In addition to Coryphodon, sp. ; Diacodon, cf. 

 alticuspis; Pelycodus, near P. jarrovii; cf. Pachyaena gracilis; 



