NO. I LOWER EOCENE MAMMALIAN FAUNAS — GAZIN 45 



Undetermined palaeanodont edentate 



Dr. Peter Robinson has recently brought to my attention an edentate 

 toe bone that he encountered during his curatorial work on the Eocene 

 collections at Yale Peabody Museum. It has Marsh's field No. 888 

 and was collected by J. Heisey in 1876 at Bitter Creek. The specimen 

 is a third metacarpal from the left foot. The proximal extremity very 

 closely resembles that in McIII of Pentapassalus pearcei and has 

 about the same diameter. It is, however, about 25 percent longer, 

 the shaft appears a little more slender, and the tubercle for the pars 

 brevis of the extensor muscle is not nearly so robust. In comparison 

 with the forefoot of much larger Metacheiromys dasypus figured by 

 Simpson (1931) the dorsal margin of the proximal articular facet 

 does not appear to be deflected so far distally on the shaft, and the 

 lateral portion of the proximal extremity shows very little surface for 

 articulation with the unciform. 



RODENTIA 



PARAMYIDAE 



Most of the paramyid material from the various localties and 

 horizons in the Wasatch has been examined by Dr. A. E. Wood, as a 

 part of his study of this rodent family, and recognition of the fol- 

 lowing genera and species result from identifications he has fur- 

 nished me of the better materials. 



PARAMYS EXCAVATUS Loomis 

 (Plate 4, figure 8) 



This comparatively small species of Paramys would appear to be 

 represented only in the La Barge and lower levels of the Knight. 

 Two lower jaws were obtained from the exposures low on the escarp- 

 ment to the west and southwest of Elk Mountain in the Fossil Basin 

 and one jaw (see pi. 4, fig. 8) came from the Bitter Creek locality. 

 A lower jaw in the collection of Miller and Granger shows this 

 species is represented in the horizon at Knight Station. Five lower 

 jaw portions and a maxilla have been added to the La Barge collec- 

 tion, so that the species is now represented by 10 specimens in the 

 later fauna. 



PARAMYS COPEI Loomis 



Paramys copei is rather well represented in the La Barge fauna 

 and two additional jaws and a maxilla have been added to the col- 

 lection since 1952. 



