landscape. It frequently alters the course of a 

 stream and changes the topography. It intro- 

 duces water into the scene. It nourishes new 

 plant-life. It brings new birds. It provides a har- 

 bor and a home for fish throughout the changing 

 seasons. It seizes sediment and soil from the 

 rushing waters, and it sends water through sub- 

 terranean ways to form and feed springs which 

 give bloom to terraces below. It is a distributor 

 of the waters; and on days when dark clouds 

 are shaken with heavy thunder, the beaver dam 

 silently breasts, breaks, and delays the down-rush- 

 ing flood waters, saves and stores them ; then, 

 through all the rainless days that follow, it slowly 

 releases them. 



Most old colonies have many dams and ponds. 

 A dam is sometimes built for the purpose of 

 forcing water back and to one side into a grove 

 that is to be harvested for food. In many cases 

 water flows round the end of a dam, and in mak- 

 ing its way back to the main channel is inter- 

 cepted by another dam, then another; and thus 

 the water from one small brook maintains a clus- 

 ter or chain of pondlets. 



74 



