PETERSON: A REVISION OF THE ENTELODONTIDAS 69 
deposits as late, or perhaps later, than the lower Harrison beds of Nebraska, in 
which the type of Dinohyus was discovered. 
In this connection it is of interest to note that a portion of an astragalus of an 
Entelodont of very large size was found in 1901 on the surface near the top of the 
upper Harrison beds in the upper Niobrara valley. This fragment (No. 1548, Carn. 
Mus. Cat. Vert. Foss.) although considerably worn by the elements, plainly indicates 
characters that are different from those in the corresponding bone of Dinohyus. 
Not only is the bone larger in size, but its sustentacular facet is proportionally of 
greater vertical convexity and the distal portion of the bone is produced anteriorly 
to a much greater extent than in Dinohyus. This peculiar feature of the astragalus 
under description would seem tojindicate that the tarsus of this genus (Ammodon ?) 
had a somewhat different angle. 
Sprecres THe Genertc Location or Wuicr is Dousrrut. 
Elotherium imperator Leidy. 
Type: A canine, an incisor, and a portion of the crown of a premolar tooth. 
Horizon: Middle John Day beds? 
Locality: Bridge Creek, and John Day River, Oregon. 
Locality of Type: National Museum, Washington, D. C.?* 
The first specimens of Entelodonts, which Professor Leidy reported from the 
John Day Basin in 1873 (58, pp. 217, 320), are altogether indeterminable generically 
and specifically and consequently inadequate as types. “ Hlotheriwn imperator” 
should therefore be regarded only as an historical record of the first report of the 
existence of Entelodonts in the John Day formation. 
Elotherium superbum Leidy. 
Type: An incisor tooth. 
Horizon : Miocene ? 
Locality: Douglass Flat, Calaveras County, California. 
Locality of Type: Unknown to the writer. 
The type of “ Hlotheriwm superbum” is altogether inadequate, and its geo- 
logical horizon is apparently uncertain. The record (49, p. 175; 50, p. 388) of this 
species should be regarded as only possessing value from the standpoint of history 
and geographical distribution. 
26 No catalog number at this writing has been given to the specimens. 
