6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 131 



Protadjidamno, only Epihippus, Amynodon, and Protoreodon are 

 common to the two, and the genera Mytonolagus, Rapamys, Eomoro- 

 pus, Epitriplopus, Poitacemylus, Diplobttnops, Leptotragulus, Lep- 

 toreodon, and possibly Desmatotheriiim and Dilophodon are charac- 

 teristic of the Uintan. Some of these ahnost certainly gave rise to later 

 types in the Oligocene but the genera in the latter group are not ac- 

 tually known in Duchesnean time. The genera Sciiiravtis, Limnocyon, 

 and Hyopsodus are survivals from Bridgerian time and Miacis ranges 

 through most of the Eocene. 



The evidence for regarding the fauna as upper rather than lower 

 Uintan pertains to the presence of Mytonolagus, the possible Pro- 

 tadjidamno, and particularly to the stage of development shown in the 

 Protoreodon and Diplobunops material. On the other hand, the pres- 

 ence of Sciuravus (doubtfully this genus according to Wood), Lim- 

 nocyon, and Eomoropus might suggest an earlier horizon, but these 

 are comparatively rare forms in Uintan deposits and their absence 

 heretofore in beds as, late as Uinta C is not nearly so significant as 

 the fact that the agriochoerids are distinctly advanced over those of 

 Uinta B time. 



Question as to whether the Badwater fauna should be correlated 

 with that from Myton pocket or with that known from the Randlett 

 member may well have little significance. Protadjidamno is not known 

 from Myton pocket but the Badwater specimens are stated by A. E. 

 Wood to consist of incisors only, so can scarcely merit serious debate. 

 Mytonolagus is known from both levels but the Badwater form is a 

 different species. Dilophodon ("Heteraletes") might suggest a rela- 

 tionship to the Randlett, but Uinta collections in the U. S. National 

 Museum show that this form is present also in the Myton fauna. 

 A slight evidence favoring the Myton fauna is seen in the artiodactyl 

 species represented. Of the Badwater forms, Protoreodon pumilus 

 is evidently present in all three occurrences, but P. petersoni and 

 probably P. pearcei are known only in the Myton fauna. Also, the 

 Diplobunops from Badwater resembles the Uinta form D. mutthemi 

 more closely than it does the broad-skulled D. crassus. It is entirely 

 possible that, although a difference in stratigraphic level has been 

 described for the Myton pocket and Randlett occurrences, the differ- 

 ences that may be pointed out are of ecologic significance, as sug- 

 gested by the rather different nature of the deposits. The beds at 

 the Myton pocket and Randlett occurrences received sedimentary 

 materials from quite different rock sources. I have been unable to 

 detect any change which can be regarded as evolutionary between 

 forms common to the two levels. 



