BEAVER DAMS. 



115 



map. About six miles southeast of Lake Michi- 

 game, and two miles south of the Washington Mine, 

 this series of structures, seven in number, is found, 

 of which a representation is given in Plate XII. 

 They commence at the entrance of a narrow gorge 

 between hills of considerable elevation, and are dis- 

 tributed on a gradually descending line of one hun- 

 dred and sixty feet, the lowest being constructed upon 

 the verge of a nearly precipitous fall of about one 

 hundred feet. Their size and height are sufficiently 

 indicated by the following measurements, which were 

 made when I first visited them in 1866, and for the 

 opportunity of doing which I am indebted to Mr. 

 John Armstrong, one of the officers of the Washing- 

 ton Mine : 



The second and third measurements given were 

 from the highest part of each structure respectively. 

 Taken together, these dams are quite remarkable. 

 The upper one, which is large throughout its entire 

 extent, forms a pond covering about ten acres of land. 

 A dense forest of hard wood overspreads the sur- 

 rounding hills, on the slopes of which a beaver-slide 

 down into the pond is occasionally seen. At the 

 upper end of the valley there is a beaver canal cut 

 through the low ground two hundred and fifty feet in 



