114 THE AMERICAN BEAVER. 



sets back its pond to the one immediately above, in 

 some cases two and even three feet in depth, the fall 

 of water at each dam ranged from one to three feet. 

 In times of freshet this river, although but a small 

 stream, passes a considerable volume of water. I 

 have seen it flow over the crests of these dams a foot 

 deep, which, as it must occur, more or less, with 

 every copious rain, subjects these structures to a severe 

 test. Having seen them both before and after such 

 occurrences, there was no injury observable that could 

 not be speedily repaired. A detailed description of 

 these dams, with their respective measurements, is 

 scarcely necessary. Those higher up, on the same 

 stream, are much larger, although the stream itself 

 diminishes to a mere brook. One of these in particu- 

 lar, on account of its great length, will be hereafter 

 described. 



Dams are often found upon small mountain streams, 

 and in the narrow gorges through which they flow. 

 They are constructed in the same manner as the ordi- 

 nary stick-dam, but are deserving of notice from the 

 nature of the localities in which they are erected. 

 It seems to be no hinderance to such a use of these 

 rapidly descending streams that the ponds thus formed 

 must be extremely short and narrow, and consequently 

 incapable of affording much protection. Many of the 

 dams in the declivities of the Rocky Mountain chain, 

 and in other mountain districts, are constructed in 

 situations precisely similar to that of the series about 

 to be described, and for this reason the latter are 

 especially interesting. 



To find an illustration of dams of this kind it is 

 necessary to go without the area embraced in the 



