BEAVER DAMS. 87 



Ely Branch of the Esconauba River. Across this 

 brook, and about half a mile below the point where 

 it emerges from the lake, the dam was constructed. 

 It was undoubtedly small at first, but was raised and 

 extended in course of time, until it reached the base 

 of the hills on either side. At this point the hills 

 approach each other within three hundred feet, while 

 immediately above it they recede both to the right 

 and to the left, and back, near the outlet of the lake, 

 close in again, thus forming an amphitheatre of hills, 

 with a slight depression at the outlet, and another de- 

 pression to the right, and inclosing a level area of 

 about one hundred acres of land. The large pond 

 created by the dam, and which is known as Grass 

 Lake, overspreads about sixty acres of this level area. 

 A forest of heavy timber covers the whole tract with 

 the exception of the pond, and of a narrow fringe of 

 beaver meadow here and there. Along the skirts of 

 the pond, in its shallowest parts, trees, though dead, 

 are still standing, from which it is evident that the dam 

 now maintains the pond at a higher level than in for- 

 mer years, or, in other words, that it has been raised 

 to a higher level within the lifetime of these trees. 

 These several features of the landscape are distinctly 

 seen in the engraving. For a large dam, and the 

 formation of a large pond, which were to result from 

 the labor of many years bestowed by many successive 

 generations of industrious beavers, this site was not 

 only well selected, but it afforded greater advantages 

 than any other within the area indicated on the 

 map. 



At the place where it is constructed the ground is 

 neither soft nor alluvial, but composed of iirm earth, 



