96 THE AMERICAN BEAVER. 



manner of repairing their dams, that they assume, in 

 course of time, the highly artistic appearance upon 

 the lower slope which the engraving displays. The 

 sticks, poles, and billets of wood, when laid upon the 

 face of the dam, impart to this slope its regular and 

 symmetrical form. When first constructed, as before 

 remarked, and when at their lowest stages, they are 

 extremely rude, and only take on the appearance in 

 which they are usually seen after they have been 

 maintained for a long series of years. Fresh beaver 

 tracks are usually seen imprinted upon the soft earth 

 on the crest of these dams, and fresh beaver cuttings 

 are often found upon their lower faces, thus showing 

 that they are in the constant habit of traversing and 

 repairing the works. There is generally no difficulty 

 in walking over the larger dams with dry feet, by 

 keeping on the lower slope, except near the ends, 

 where the structure is not usually strong enough to 

 bear up the weight of a man. Upon the sloping face 

 of the great curve of Grass Lake Dam twenty men 

 could stand together without making any impression 

 upon the structure. The series of dams on the Carp, 

 shown upon the map, are similar to this, and would 

 average about three feet in height. While fishing in 

 this stream for brook trout, three of us found no diffi- 

 culty in landing from our boat upon their lower slopes, 

 and drawing the boat over without injuring them in 

 any respect. 



The following measurements will indicate, in an- 

 other manner, the size and proportion of parts of this 

 great structure, as well as convey some impression of 

 the amount of solid materials employed in its erection : 



