THE BEAVERS OF NORTH AMERICA 27 
hard to say where one begins and the other ends) 
of eighteen feet in length and about six inches in 
diameter at the larger end are frequently used, and 
shorter pieces of from one foot in length upwards 
and having a diameter of eight or nine inches are 
not uncommon. Just what purpose these short 
and very heavy pieces serve is difficult to say. 
They certainly add weight, but is that much 
advantage? They cannot be said to add to the 
structural strength, but perhaps when the mud 
freezes and they become very firmly locked in they 
offer an insurmountable obstruction to any animal 
that may attempt the difficult task of digging into 
the lodge. 
As a rule the bulk of the material employed con- 
sists of long sticks of one to three inches in diameter 
at the larger end and a great deal of short stuff of 
variable size which forms an irregular network. 
Fibrous roots add greatly to the strength of the 
work by binding together all the loose material © 
so solidly that it is a task of the utmost difficulty 
for a man to pull it apart unless he is armed with 
a pick-axe or crowbar. A well-built lodge will 
even withstand the destructive power of running 
water. In Newfoundland I noticed one house 
while it was being built and remarked on the 
thoroughness of the work. During the following 
spring the heavy rains and melting ice and snow 
caused a flood, which raised the river about eight 
or ten feet above the normal level. Needless to 
