NO. 2 A STUDY OF MENISCOTHERIUM — GAZIN IJ 



Four Mile Creek, and Dad. Several specimens of Homogalax or 

 a closely related form in the rather scant collections from the Wasatch- 

 ian beds near Dad, Wyo., are noteworthy because no isectolophid is 

 represented in the contemporary La Barge fauna. Homogalax and 

 Meniscotherium, small M. tapiacitis, have been reported together 

 only at Bitter Creek. 



Discrepancies in the distribution of the smaller artiodactyls Diaco- 

 dexis and Hexacodus may also merit discussion. Diacodexis, while 

 widely distributed, is abundant only in the Big Horn Basin. Hexa- 

 codus, on the other hand, with the exception of a single Gray Bull 

 specimen, has so far been found only in southwestern Wyoming. 

 Distribution of these may in a general way be related to the environ- 

 ment of Meniscotherium, but it must be noted that relatively scant 

 remains of Diacodexis have been found in nearly all Meniscotherium 

 occurrences. Diacodexis, however, is outnumbered by Hexacodus 

 better than 5 to 1 in the La Barge fauna. 



Of the remaining subungulate and ungulate forms of the Wasat- 

 chian, Hyopsodus is nearly universal in occurrence. It is possi- 

 bly of more than casual interest, however, that with the exception 

 of three specimens of H. walcottianus reported from the Lost Cabin 

 beds and one from the New Fork, the larger species of Hyopsodus, 

 including H. browni, H. powellianus, and possibly H. walcottianus, 

 seem to avoid Meniscotherium or vice versa. Equally widespread 

 Hyracotherium, however, would appear in no way influenced by the 

 range of Meniscotherium or the factors controlling its distribution. 

 The same may be said of Heptodon and Lambdotherium, although 

 these are known only from later portions of Wasatchian time, and 

 Heptodon seems to have a more restricted geographic range, but 

 unrelated to the distribution of M eniscotherium. 



Coryphodon has a distribution which in some ways appears at 

 variance with that of Meniscotherium, but having collected the two in 

 close proximity at various localities in the Knight, I suspect that 

 abundance of the former is more closely correlated with time. It 

 seems everywhere well represented in Gray Bull levels of the Will- 

 wood, Wasatch, and San Jose formations and particularly abundant 

 in the lowest levels, to judge by its occurrences in the Washakie and 

 Fossil Basins. It is missing or rare in Lysite levels, except pos- 

 sibly for the Fossil Basin, but then again it is not rare in the later 

 Wasatchian of the Wind River and Green River Basins, in the latter 

 being more closely associated with large Meniscotherium. 



The scarcity of the herbivores Esthonyx and Ectoganus or Sty- 



