20O Roosevelt Wild Life Bulletin 



them, in most cases they had decayed and settled down to the level 

 of the surrounding surface, showing that a comparatively short 

 period of time is necessary to form a meadow. Farther down on 

 the South Fork of Elk Creek, below Yanceys, are old dams which 

 were broken through by high water twenty-five years ago. 



Description of Beaver. As muskrats often inhabit beaver ponds, 

 Park visitors unfamiliar with either animal should bear in mind that 

 the adult beaver is much larger than the muskrat. In appearance a 

 beaver is somewhat like a big, overgrown muskrat, with a broad, 

 flat, scaly tail. Even the brown color of the fur is not at all unlike 

 a muskrat's. The total length of an adult beaver is about 42 inches, 

 of which 16 inches is the tail, — the black, scaly portion being about 

 9 inches long and 4 inches wide. It will weigh 35 pounds and 

 upward, even reaching 60 or more, although that is unusual. The 

 hind feet are broad and webbed and the second toe has a curiously 

 split nail. This latter is said to be used for combing the hair, but 

 I do not know of anyone who has seen it so used. The forepaws 

 are small, and the animal uses them much as hands, holding sticks 

 when gnawing the bark from them, and also using them for digging 

 up bottom mud and sod which are carried to any desired spot for 

 building purposes, holding the material with the paws against the 

 chin. 



The fur is of two kinds, — the close, dense undercoat, and the long, 

 outer guard hairs. These latter are usually plucked out in preparing 

 the fur for the trade. 



The huge incisors or front teeth are the tools with which the beaver 

 does his wood cutting, and are eminently adapted to the purpose 

 (figure 49). These teeth on the front side are composed mainly of 

 a thin edge of very hard enamel, with a broad layer behind of rela- 

 tively soft dentine. As the tooth is used the softer dentine wears 

 away much faster than the enamel, so that there is always a sharp 

 chisel edge on the front of the tooth. These teeth grow continuously 

 during the life of the animal, and if by any accident one is broken 

 or so injured that it does not oppose the one in the opposite jaw, 

 the latter may grow out to such an extent as to seriously incon- 

 venience the animal, if not to cause its death from inabi 1 ity to feed. 

 The incisors are long, and the hidden portions have, much curvature 

 within the skull and lower jaw. Morgan gives the radius of the 

 curvature of the upper incisors as one inch, and of the lower, one 

 and three-quarters inches The front of the incisors is deep orange 



