1915.) Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 309 
(No. 14785).' It was found in association with Lambdotherium, Eotitanops 
borealis and other characteristic Lost Cabin forms. Fragments of both — 
maxillee are preserved, one side supporting p*-m*. The teeth measure a little 
larger than the type of M. chamense but I can see no reason for not referring 
it to this species. On p* the mesostyle is rather more sharply defined than 
on any New Mexican specimen but this is an individual character seemingly, 
since all stages of development of this style are observed in the New Mexi- 
can specimens; some are without trace of it while others have it pronounced 
but never so highly developed as on the molars. From the typical Lost 
Cabin beds, on Alkali Creek, are two specimens of lower. jaws (Nos. 2972, 
14737), both of which are referable to M.chamense. The presence of these 
specimens of Meniscothervum in the Lost Cabin beds of Wyoming is a strong 
point in the correlation of those beds with the upper beds (Largo) of the 
New Mexican Wasatch. 
Measurements of No. 14785 are p ies b4.5 mis m.* = 26.7 mm. 
Meniscotherium chamense terrerubre Cope, 1881. 
Meniscotherium terrerubre Corr, 1881, Proc. Am. Phil. Soc., xix, p. 493; 1885, 
Tert. Vert., p. 496, pil. xxvf, figs. 12-14, xxvg. 
Syn. Hyracops Socialis Marsu, 1892.” 
Type, Amer. Mus. Cope Coll. No. 4410, a left maxilla, with p*-m* and a 
lower jaw fragment with p’r. in doubtful association; Wasatch of the San. 
Juan basin, N. Mex. D. Baldwin, 1881. 
Distinctive characters: m'* = 26.5 mm.; p*-m? = 37.5 mm. Lower 
molars as in M. chamense. 
Cope differentiated this species from M..chamense by size and by the 
“flattened form of the external faces of the true molars and the absence of 
the convexity of the external bases of the crown.” These differences of 
form I am not able to make out from the types themselves, although Cope’s 
drawings show them. | 
The lower jaw fragment associated with the type probably belongs to a 
smaller individual, judging from other specimens in the collection where the 
association of upper and lower teeth is beyond question. ; 
I refer to this large form the skull and jaws (No. 4412) used in the — 
composite mounted skeleton, also Nos. 4413, 4417, both of which were 
figured by Cop in his Tertiary Vertebrata. 
1W. Granger, loc. cit., p. 206 (M. terrerubre). 
2 Amer. Journ. Sci., 1892, p. 447, figs. 1, 2. 
