BEAVER DAMS. 103 



and lengthwise with the flow of the stream instead or 

 transversely. In general the large ends of the poles, 

 and of the limbs with their branches attached, were 

 up stream, which of itself would tend to strengthen 

 their hold upon the bottom. Upon these materials, 

 which were compactly arranged, earth and mud, in 

 small quantities onl}^, were accumulated for down 

 weight, and to fill up the intervening spaces; but it 

 was confined to the central and upper portions. On 

 the upper margin, which was to form the water face 

 of the dam, small sticks were used, together with 

 loam, intermixed with fine roots, for the purpose of 

 arresting the flow of the water through the rudely- 

 arranged materials of the dam. At this stage it was 

 extremely rude, and devoid of those striking charac- 

 teristics which these dams assume with age. 



The manner in which they repair their dams is 

 both curious and interesting. It will be sufficient 

 here to state that ordinary repairs are made, when- 

 ever they seem to be required, by each beaver acting 

 independently, and without any concert with his 

 mates. In case of a breach in the structure, several 

 of them have been seen working together for its 

 restoration. They usually go down to the dam nightly, 

 one after the other, and as they pass along its margin, 

 each, upon his own motion, does such work upon it as 

 he chooses to perform. In another connection some 

 facts will be stated upon this subject. 



