IO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 149 



Clarkforkian or latest Paleocene through or nearly through Wasatch- 

 ian or early Eocene time. As noted by Van Houten ( 1945 ) only two 

 Paleocene occurrences are known: a single specimen, the type of 

 Meniscotherium priscum Granger (now lost), came from the Clark 

 Fork beds in the Clark Fork Basin ; and two lower premolars, one 

 of which (Dp 4 ) was made the type of Meniscotherium semicingu- 

 latum Russell, came from beds of about this age near Cochrane 

 in Alberta, Canada. The small species of Meniscotherium repre- 

 sented in the early Wasatchian at the Bitter Creek and Red Desert 

 localities in southwestern Wyoming, earlier (Gazin, 1962) compared 

 with M. priscum, I now find cannot logically be distinguished from 

 M. tapiacitis. 



Although Granger (1915) has listed M. tapiacitis as belonging 

 in the Largo fauna of New Mexico, the single specimen of this very 

 small form may have come from much lower beds, recalling Cope's 

 statement that it was collected "from beds of probably lowest Wasatch 

 age. . . ." The locality is given by Granger as "Alto la Zerta," but 

 I have been unable to find this on any map. Possibly his conclusion 

 that Cope's statement was in error was based on the distribution of 

 M. chamense. 



With the possible exception of M. tapiacitis, Meniscotherium, as 

 noted by Granger (1915), Van Houten (1945) and Simpson (1948), 

 is essentially missing from the Almagre facies, but is abundantly 

 represented by M. chamense in the Largo facies of the San Jose 

 sequence in New Mexico. Again in the Wind River Basin, as M. 

 chamense, it is known, though sparsely, only in the latest, or in this 

 case, the Lost Cabin fauna. I agree, however, with Van Houten 

 and Simpson that because of the vagaries in distribution this does 

 not warrant a correlation in time between Largo and Lost Cabin as 

 Granger (1915) supposed. 



There is no record of Meniscotherium in any of the early Eocene 

 or Wasatchian horizons of the Big Horn Basin, following its occur- 

 rence in the latest Paleocene Clark Fork beds of the area. On the 

 other hand it is apparently found at all levels in the Wasatchian beds 

 of the southwestern part of the State, except in the southern part of 

 the Fossil Basin and the eastern part of the Washakie Basin. Small 

 M. tapiacitis is found in the lower levels of the Knight on both sides 

 of the Rock Springs uplift and has been reported well up in the see- 

 tion, possibly as late as Lysitean, on the east side of the uplift, in the 

 western part of the Washakie Basin near Bitter Creek. M. cf. 

 robustum is recorded from an intermediate horizon of the Knight 



