THE BEAVERS OF NORTH AMERICA 49 
cross-pieces would add to the strength of the dam, 
and they would be easily dislodged by the pressure 
of the flowing water. Whereas when placed with 
butts upwards and headed against the current, the 
points are forced against the bed of the river and 
as weight is added to them they offer a barrier of 
great strength, capable of resisting any ordinary 
pressure of water. When the supply of water is 
too limited, the beaver take the utmost care to see 
that none is wasted, and the dam is coated with 
unusual care to render it practically watertight 
even towards the ends, and every tiny trickle is 
stopped, sometimes by little dams only a few 
inches long, just a handful or two of sod placed in 
exactly the right position, perhaps some distance 
from the actual structure. If during the autumn 
these are trodden down or broken they will nearly 
always be repaired within a few hours, so careful 
is the supervision of the beaver. 
For some reason which can only be guessed at, 
the beaver nearly always leave a roadway across 
the dam leading from the pond to the outlet. This 
is also much used by other animals of aquatic 
habits such as mink, musquash and otter, and 
though occasionally we also find a well-beaten 
path running along the dam from bank to bank 
this is not a beaver path. More often it is the 
work of foxes, deer, lynx and other prowlers of 
the woods, as well as man, who finds these 
“bridges” most convenient. Many a time have 
R.B. E 
