82 THE AMERICAN BEAYER. 



that immediately above. In this manner every por- 

 tion of a stream is appropriated by them for the pur- 

 poses of habitation. 



The accompanying map, which embraces but a 

 fragment of the area described, was drawn by Mr. 

 L. K. Dorrance, chief engineer, and afterwards revised 

 by William H. Steele, Esq., assistant engineer of the 

 Marquette and Ontonagon Railroad, from materials 

 furnished by the author. Each section delineated is 

 a mile square, the sections corresponding with those 

 upon the official United States Township maps. With 

 this integer of measurement, the distances between 

 the several dams and the size of the several ponds 

 can be readily ascertained as well as the actual lo- 

 cation of each. The size of some of the ponds may 

 be somewhat exaggerated, but the map is substan- 

 tially accurate. For convenience of reference the 

 dams are numbered consecutively. The sites of a 

 large number of lodges, the location of the principal 

 beaver meadows, and of several beaver canals are also 

 indicated on the map. 



The dam^ is the principal structure of the beaver. 

 It is also the most important of his erections as it is 

 the most extensive, and because its production and 

 preservation could only be accomplished by patient 

 and long-continued labor. In point of time, also, it 

 precedes the lodge, since the floor of the latter and 

 the entrances to its chamber are constructed with 

 reference to the level of the water in the pond. The 

 object of the dam is the formation of an artificial' 

 pond, the principal use of which is the refuge it affords 



^ O-ko'-rain, beaver dam. 



