76 CASTOROI.OGIA. 



theory in the construction of a mud-dam, for in this case the whole 

 plan has to be conceived and perfected by the beaver. Every particle 

 of material employed in a work needing hundreds of cubic yards, is 

 gathered and placed by the small, though nimble fore feet of the 

 beaver, and to complete the task, requires the highest skill and 

 all the perseverance the animal has ever been supposed to possess. 

 To enumerate the various forms assumed by the dam would be to 

 catalogue almost every change of landscape effect, for the beaver 

 always adapts himself to his situation, and most particularly in the 

 case of the dam. 



Mr. Lewis H. Morgan in his book " The American Beaver and 

 his "Works, ' ' gives special prominence to the various forms assumed 

 by the dam, and devotes over fifty pages to this feature alone, his 

 treatment being most interesting, yet by no means exhausting all 

 that could be said. 



One other accomplishment, which by some is considered more 

 extraordinary than all the other works, is the formation of the canal. 

 The evolution of this is, however, more easily traced and understood, 

 nor does it involve such difficulties, nor exact such skill as the build- 

 ing of the lodge and the construction of the dam, though the perse- 

 verance of the animal is clearly exhibited in this undertaking. 



Admitting the fact that the beaver continually uses the same 

 path from the water to the woods, both going and returning, and 

 thus cuts or wears away the bank into a regular rut or path, into 

 which the water follows and helps to wash away a little earth every 

 time the path is used, the possible beginnings of the canal may be 

 seen. It must not, however, be supposed that this explanation 

 exhausts all the skill necessary to account for the canal ; it only 

 suggests a rational origin for the work, and when it is known that 

 in the log roll-way (referred to at the commencement of this chapter), 

 the beaver carefully clears away every obstruction of stick or stone, 

 it is only applying the same idea on a larger scale to the pathway 

 which he invariably uses and which soon becomes a waterway or 

 canal. 



