314 Bulletin American Museum of Natural History. [Vol. XXXIV, 
The type was originally described with other fossils as from the Wind 
River basin, but in 1885 the locality was definitely stated as Bighorn Valley. 
In cataloguing the Cope Collection in 1896 I referred this discrepancy to 
the collector, Dr. Wortman, who in- 
formed me that although most of his 
collections of 1880 came from the 
Wind River Valley and of 1881 from 
the Bighorn basin, he did obtain a few 
specimens in 1880 from the Bighorn 
which were at first wrongly supposed 
by Professor Cope to have come from 
the Wind River Valley, the error 
being subsequently corrected. I cite 
these circumstances, because later 
collecting indicates that this genus is 
wholly limited to the lower part of the 
Wasatch, and is a valuable horizon- 
indicator (leitfossil). This is equally 
true of Dedymictis leptomylus, de- 
scribed in the same notice as H. spei- 
rranus, as from the Wind River. It 
Hig. 2. Haplomylus speirianus Cope, is abundant in the lower part of the 
| phates fee on a ee Wasatch but has not been found in 
Creek, Bighorn basin, Wyoming. the Upper Gray Bull, Lysite or Lost 
| Cabin, where it is replaced by larger 
and more progressive species. The type specimens of these two species 
have more the appearance of specimens from the Lower Wasatch of the 
Bighorn basin than of specimens from the Lost Cabin or Lysite beds of 
the Wind River Valley. | 
It appears reasonably certain therefore that the true horizon of the type 
of Haplomylus speirianus is Lower Wasatch. Of the referred specimens 
thirty-two are recorded from the lower Gray Bull, six from the Sand Coulée, 
~ two from the Clark Fork beds, of the Bighorn and Clark Fork basins; none 
from the Wind River basin. They are all parts of upper or lower jaws with 
more or less of the premolar and molar dentition preserved; in No. 16107 
upper and lower teeth of the same individual are associated. The skull 
and skeleton are unknown. 
Hyopsodus Leidy 1870.1 hes 
Type, H. paulus from the Lower Bridger (Orohippus zone) of Wyoming. 
1 Leidy, 1870, Proc. Acad. Nat. Sci. Phila., Vol. 22, p. 109. 
