(2 University of California Publications in Geology [Vou.7_ 
teeth of the captor. The suggestion is also made that the cavern 
may have been used as a den for hibernation by various ursines, 
even as other caverns in the region are known to be used by 
bears of today. 
No specimen of bird skeleton was found with bones in proper 
place, so the probability is that the remains representing this 
class were introduced largely as in the case of the Potter Creek 
Cave specimens. Some essential difference must have existed, 
however, since the relation in numbers of the different species is 
so different in the two localities. The Cathartiformes appear in 
Potter Creek Cave represented by forty-five specimens distri- 
buted over three species. In Samwel Cave there appear but six 
specimens possibly assignable to the group. Falco peregrinus, 
represented in the former cave by four specimens, is wanting in 
the latter. The owls are represented by five specimens in the 
former and eleven in the latter, the grouse by thirty-four in 
the former as against one hundred and twenty-four in the 
latter. 
This difference of faunal proportions is perhaps most readily 
explained by the probable difference between the original open- 
ings of the caves. Let it be conceded that, as suggested by the 
respective authors, Potter Creek Cave opened by a relatively 
small chimney or two on the surface of the Pleistocene hillside 
and that Samwel Cave opened by a large chamber, the first part 
of which ran more nearly horizontally. Vultures, ravens, and the 
peregrine falcon nest in small cavities in rocky cliffs out of the 
way of small predatory mammals like the raccoons and the 
weasels. Their bones and those of their prey would accumulate 
in these pockets and eventually find their way into deeper re- 
cesses through fissures or chutes as described by Sinclair. The 
owls, however, resort to large open-mouthed caves to roost during 
much of the year, which fact would account for their greater 
abundance in Samwel Cave. Raccoons were found in abundance 
by Furlong as entire skeletons on the floor of Samwel Cave, thus 
suggesting that these animals frequented the place as a lair. 
The ground-dwelling birds, their natural prey, thus come to 
form a large proportion of the avian remains in these deposits. 
Procyonid forms are not listed by Sinclair from Potter Creek 
