J^ SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



exhibits a small protoconule but no metaconule, as in the type. 

 Whether this specimen should be referred to Palaeosyops fontinalis 

 or regarded as a large species of Eotitanops is not determined. 

 Although direct comparison is not feasible, M^ in the Cathedral Bluffs 

 specimen is only a little larger than would be required for good occlu- 

 sion with the type lower jaw of Eotitanops princeps. 



An additional specimen, U.S.N.M. No. 22766, that might also be 

 referred to P. fontinalis but which is of a somewhat larger individual 

 than the Princeton specimen was found very near the top of the red 

 beds in the Oregon Buttes area, immediately to the southwest of 

 Continental Peak and near its base. The red beds and the overlying 

 greenish sequence here have been mapped as belonging to the Cathe- 

 dral Bluffs member. The material consists of numerous bone frag- 

 ments and portions of upper teeth, but with only P^-P^ nearly complete 

 and the lingual portions of P* and M^ preserved. 



The type of Palaeosyops fontinalis was found by Cope "on a bluff 

 on Green River near the mouth of the Big Sandy Creek, Wyoming." 

 Osborn considered the horizon represented as Bridger A, but I have 

 some doubts as to the existence of a distinctive unit of true Bridger 

 beneath that defined by Matthew as "B." The specimen may well 

 have come from a sandy zone or lentil high in the Green River forma- 

 tion, as developed in the Bridger Basin. In any case there is sugges- 

 tion of an approximate correlation with the upper part of the Cathedral 

 Bluffs member in the Washakie Basin, inasmuch as the locality data 

 for the Princeton specimen show it as coming from a horizon high 

 beneath the Laney shale contact (sec. 4, T. 15 N., R. 93 W., evidently 

 fossil loc. I on Morris's map, 1954, p. 198). 



Palaeosyops fontinalis is not particularly close to typical Bridger 

 Palaeosyops, as indicated by both Cope and Osborn. It is very much 

 smaller than P. paludosus. As noted by Peter Robinson in his study 

 of the Huerfano material, Palaeosyops fontinalis morphologically 

 resembles Eotitanops borealis. P. fontinalis is in all probability an 

 intermediate stage in a line of development from typical Eotitanops to 

 Palaeosyops, as well as being intermediate in size between E. borealis 

 and P. paludosus. Whether this stage should be referred to Paleosyops 

 or Eotitanops seems a rather arbitrary matter. Since the Cathedral 

 Bluffs fauna on other evidence should no doubt be regarded as Wa- 

 satchian rather than Bridgerian, one might be justified in allocating 

 P. fontinalis to Eotitanops. 



