NO. I LOWER EOCENE MAMMALIAN FAUNAS — GAZIN I7 



The stratigraphic position of the occurrences referred to as the 

 Dad locality appears similar to that for the La Barge area relative 

 to the Tipton tongue, and the faunas represented are similar in the 

 identity of several species. Among those in common may be men- 

 tioned Chlororhysis knightensis, Paramys copei. Par amy s major, 

 Ambloctonus major, Vulpavus asiiis, Hyopsodus wortmani, Cory- 

 phodon, cf. radians, Hyracotherium vasacciense, Hyracotherium, cf. 

 craspedotiim, Lamhdotherium popoagicum, and Heptodon ventornm. 

 Several of these are not particularly significant as to the horizon of 

 the Knight represented but the occurrence of Lamhdotherium would 

 seem to limit it to Lostcabinian time. There are, nevertheless, a 

 number of differences that are noteworthy, but which can possibly be 

 attributed to local environment or ecology. The absence of Menisco- 

 therium, so abundant in the La Barge fauna — missing from all 

 horizons on the east side of the Washakie Basin — must surely be 

 related to ecology. Not so easily explained perhaps are certain forms 

 that seem rather primitive for this level, such as indicated by the 

 materials that have been tentatively referred to Didymictis protenus 

 and Viverravus acutus, and the small tooth referred to Esthonyx. 

 Moreover, a Hyopsodus the size of Lysite H. hrowni is not repre- 

 sented in the rather numerous remains of this genus at La Barge. 

 Particularly surprising is the discovery of isectolophid remains 

 closely resembling Homogalax. Too much stress, however, should 

 not be placed on this because of the recognized survival of the isecto- 

 lophid line into still later Eocene time. The possibility that the lowest 

 exposures along the base of the Baggs-Dad escarpment, where it 

 reaches its greatest height, may include beds older than Lost Cabin 

 should not be disregarded, but unless faulting is involved, surely 

 beds of Gray Bull age would not be exposed so near the Tipton 

 tongue. 



New Fork. — Of especial importance are the New Fork or Ca- 

 thedral Blufifs exposures along Alkali Creek in the same general 

 area as those for the La Barge fauna but somewhat farther east of 

 the Green River. Alkali Creek, a dry stream bed most of the year, is 

 roughly parallel to the Green River, descending northward to where 

 it joins the Green River near its confluence with the New Fork. 

 Exposures of the New Fork beds are typically developed along the 

 south side of the New Fork to the east of Big Piney, and on both 

 sides of Alkali Creek. The most productive localities were found 

 to be the series of buttes on the west side of Alkali Creek from its 

 mouth southward for a few miles, beyond which the fluviatile series 



