l6o CASTOROLOGIA. 



then build on the top of these, so as to fix them firml3^ It would 

 require to be seen to appreciate the great skill displayed in its con- 

 struction ; as I think it would tax the energies of a Bateman or a 

 Gale to make a better with the same materials. If any damage does 

 occur, they immediately find it out and repair it. I have seen them 

 swim along the edge of the embankment, carefull}^ examining it to 

 ascertain the part most needful of repairs, then go to work with a will 

 to rectify it. The dam is now seventy-eight yards long of still water. 



"Besides the dam already mentioned, upon which they bestow 

 great care in its construction, owing to their house being built in it, 

 they have other seven, some larger, some smaller ; one of them hav- 

 ing an embankment 105 feet long, and an average depth of three 

 feet. These serve as places of refuge if the beavers are disturbed 

 when out roaming about in quest of food or felling the trees, also as 

 a waterway for conveying their food, when storing it past for winter. 



' ' In the construction of their dwelling the same kind of mate- 

 rials are used. As to how they build it : you must understand that 

 for a considerable distance along one side of the stream or burn the 

 ground rises in a steep bank, but about twenty yards above where 

 they began to build the embankment for the dam, there was a small 

 level spot which they selected. Then at the bottom of the water they 

 burrowed in three or four feet, rose up eight or ten inches, scooped 

 out a space large enough to hold themselves, broke a hole in the 

 surface about six inches in diameter, then began to cover it over 

 with sticks, grass, and a few stones, always keeping it open in the 

 centre by placing a few sticks perpendicularly, so as to act as a ven- 

 tilator, and as the water rose in the dam and the family increased 

 they continued to build and enlarge the house, cutting their way up 

 and forming their chamber or chambers inside, until it had now at- 

 tained the following dimensions at the surface of the water (which is 

 here about four feet deep), viz. — height about five feet, length and 

 breadth about nine feet, having a door at both sides placed at the 

 bottom of the water so as to prevent their natural enemies from fol- 

 lowing them, chief among which is the wolverine, although happily 

 for both them and us there are none of these here to disturb them. 



