A Skeleton of Great Fossil Beaver, Castoroides Ohtoensis. 169 
The long, stout tail, with its thick-winged, bifurcate lateral 
processes, though relatively much narrower than the skeleton tail 
of the recent beaver, was, nevertheless, pretty surely flattened in 
the same direction, though not to the same extent. It evidently 
was not cylindrical as in the rat, and it could not have been com- 
pressed, as in the muskrat. 
The shoulder, elbow, hip, knee and tarsal joints not only have © 
provision for close folding, but give evidence that they were folded 
at sharp angles as a habit, showing that the creature held its body 
low. 
If it felled trees and was aquatic in its habits, would it be an 
inexcusably rash suggestion that there may have been colonies of 
them employed in dam building, and that our subject may have 
helped to make the pond in the silt of which he was finally buried ? 
The silt was immediately above drift gravel. 
In three cases within the writer’s knowledge, fragmental or 
entire incisors of Castoroides have been found associated with Mas- 
todon remains. 
