200 THE AMERICAN BEAVER. 



depended upon the dam, and the source of supply 

 before named, it was uniformly about eighteen inches 

 deep. From the second dam the canal continued at a 

 foot higher level for the distance of two hundred and 

 ninety feet, where it terminated at the base of the 

 hard-wood lands at a distance of five hundred and 

 seventy-nine feet from the river. Its average width 

 was about four feet, and it had an unobstructed chan- 

 nel of about eighteen inches deep from one end to the 

 other, with the exception of the dams. The run-ways 

 of the beavers over these dams were very conspicu- 

 ous. They were shown, as in the other cases, by a 

 depression in the centre formed by traveling over 

 them in going up and down the canal. At the mouth 

 of the canal the river was not deep enough for a 

 beaver to swim below its surface out into the stream. 

 To obviate the difficulty, a channel, twenty-five feet 

 long and a foot or more deep, was excavated in the 

 bed of the river far enough out to carry them into 

 deep water. The materials were thrown up in an 

 embankment on the side below the excavation, ap- 

 parently lest the current of the stream should carry 

 them back into the channel. The excavation and the 

 embankment, which were plainly to be seen side by 

 side, the latter in places coming up to the surface of 

 the water, presented another striking illustration of 

 the industry as well as intelligence of the beaver. 



It is manifest from the form and general appearance 

 of this canal (Plate XXI.) that it is artificial. In ad- 

 dition to the uniformity and depth of its channel, its 

 vertical banks, the absence of a current, the sources 

 whence the water is obtained, and its actual use as a 

 channel for the transportation of wood cuttings, there 



