8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



the same time he concluded that his Morrow Creek member, which 

 overlies the Wilkins Peak, must then be equivalent to the type Laney 

 and should therefore be abandoned. 



From this it is seen that in the Bridger or Green River Basin the 

 New Fork tongue, which is evidently equivalent to the Cathedral Bluffs 

 tongue, overlies the Fontenelle or Tipton tongue, interfingers with 

 the Wilkins Peak and is overlain by the Laney member of the Green 

 River. Evidently the Wilkins Peak member is present only in the 

 Bridger Basin, so that to the east of the Rock Springs uplift the wide- 

 spread Cathedral Bluffs tongue overlies the Tipton tongue and is 

 overlain by the Laney member. 



THE MAMMALIAN FAUNAS 



The various Mammalia encountered at the several general locali- 

 ties and horizons in the lower Eocene beds of southwestern Wyoming 

 are included together in the following composite list and checked to 

 show representation in the more important localities for these horizons. 



OCCURRENCES AND FAUNAL CORRELATIONS 



The various collecting localities included in the apposing list, for 

 the most part rather general areas representing subdivisions of Wa- 

 satchian time, are discussed in following sections. To these, however, 

 are added consideration of the Four Mile Creek localities in Colorado 

 that were studied by Malcolm C. McKenna, the series of localities in 

 stratigraphic sequence on the flanks of the Rock Springs uplift that 

 were systematically developed by Henry W. Roehler, and a few 

 occurrences of lesser faunal importance that seem worthy of mention. 



Red Desert. — The locality referred to as Red Desert in the at- 

 tendant check list is a small area of buff, course-grained sandstone 

 which outcrops in about sec. 12, T. 23 N., R. 100 W., approximately 

 14 miles east of Steamboat Mountain to the north of the Rock Springs 

 uplift. The horizon here represented is near the base of Pipiringos's 

 Red Desert tongue and judged by him to be about 200 feet above the 

 Eocene-Paleocene contact. The small patch of sandstone shows much 

 evidence of wind erosion, and the rather fragmentary materials ob- 

 tained, consisting mostly of isolated teeth, would appear to be a part 

 of a residual concentration of coarser particles left by the wind. 



The fauna represented includes such characteristic Wasatchian 

 forms as Pelycodus, Esthonyx, Phenacodus, Hyracotherium, and 

 Diacodexis but evidence for an early Gray Bull equivalence is seen in 

 the condylarth Haplomyhis speirianus. A correspondence to the Four 



