l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



above the Tipton tongue is replaced by interfingering lake deposits 

 belonging to the Wilkins Peak member of the Green River formation. 



Since the preliminary statement on this fauna in 1952, 15 genera 

 have been added to the 10 (one of these, Ambloctonus, was cited in 

 error) then recognized. These represent the smaller mammals such 

 as insectivores, primates, rodents, artiodactyls, and particularly 

 carnivores, as may be seen in the foregoing list. The fauna is rather 

 closely related to that of the La Barge horizon, and about 16 species 

 survived without change of significance or taxonomic importance the 

 interval of lake encroachment during which the Tipton tongue was 

 formed. Certain species, however, may be regarded as having evolved 

 more appreciably ; suggested are those representing Cynodontomys, 

 Notharctus, Prolimnocyon, and Biinophorus. The ecologic changes 

 that accompanied the lake advance no doubt permitted or are re- 

 sponsible for a certain faunal readjustment, with migrations and 

 certain extinctions evident in the local scene, but because of the 

 climatic factor involved this may have been rather widespread. 

 Notable is the disappearance of Coryphodon, possibly also of Thryp- 

 tacodon and Ambloctonus, although these are never common and 

 could have escaped collection in the New Fork. A number of small 

 mammals are not recorded later but their marked scarcity or unique 

 representation precludes any generalizations. Newly introduced into 

 the area are such forms as Hapalodectes, Bathyopsis, and Hyrachyus. 

 Meniscotherium robustum evidently became extinct and was replaced 

 from elsewhere by a form that would appear to be M. chamense. 

 A new animal to the Green River Basin in New Fork time may also 

 be Hyopsodus walcottianus. 



Cathedral Bluffs. — Above the Tipton tongue in the Washakie 

 Basin the Cathedral Bluffs member has been found to be compara- 

 tively barren. Exploration by Smithsonian Institution parties has 

 extended from the northwest around the northern and eastern sides 

 of the basin to near the southeastward limit of the exposures, with 

 the finding of but very occasional scattered specimens. Neverthe- 

 less, collecting by William Morris for Princeton University has re- 

 sulted in representation of a fauna of respectable size. Most of the 

 Princeton material from the Cathedral Bluffs is from the zone of 

 outcrop on the northeast side of the basin, as shown on the map 

 accompanying his report (1954). 



About 15 genera are now recognized in this fauna, and though the 

 number is not significantly greater than listed by Morris, there have 

 been some changes in the names applied with a different interpreta- 



