162 THE AMERICAN BEAVER. 



for the purpose of measurement. The breach pre- 

 viously made had destroyed it for beaver use. 



POND 



Ground Plan of second Beaver Burrow at Grass Lake. 



About twenty feet above the great dam, and upon 

 the south side of the pond, is the burrow represented 

 in the above figure (Fig. 17). It ascends with the 

 bank, which it enters under the roots of a tree, is ten 

 feet long, and has a chamber twenty inches in width 

 and a foot high. It terminates under the roots of a 

 pine-tree, where its roof comes within four inches of 

 the surface of the ground. It is a good specimen of 

 the ordinary burrow. 



North of the Cleveland Mine there is a natural pond, 

 shown on the map, which will be more particularly de- 

 scribed hereafter. The canals which enter it have a 

 number of burrows upon their upper portions, one of 

 which is represented in the figure (Fig. 18). This bur- 

 row is shown in Plate XVIII., and is the one nearest to 

 the pond. It was found open at the centre and also at 

 the extreme end. The length of the passage-way from 

 the canal was eleven feet, and this communicated with 

 a chamber three feet two inches by two feet and a half 



