278 DWELLINGS OF MUSKRAT AND BEAVER—GILPIN. 
struction, we came to a hole on one side, plunging the paddle 
into which, we soon came to the waters beneath. Here now was 
the whole design complete ; a dry bed about a foot and a-half 
above the surface of the lake, covered by about a foot of roof, 
and having a submarine approach from below, into which the 
owner entered by diving. The whole cone was solidly con- 
structed from the bottom of the lake, leaving only a narrow hole 
from the bottom to the nest. The inmate must breathe through 
the loose top of the cone, as it stands surrounded by water. In 
another larger cone we pulled to pieces, we found two cavities 
unconnected with each other, but each having a separate passage 
to the water below, although the majority were symmetrically 
conical, yet we found two uneven, one witha perpendicular side, 
most probably unfinished, as they had not done building for the 
winter. In building they must place their material on the bot- 
tom of the lake, where it soon becomes water sodden, and 
having a passage open, built up above the surface of the water. 
They build at night and very rapidly, as one is surprised at see- 
ing cones standing out of the water where none were the day 
before. November finds them well housed for the winter, and 
as the ice is never frozen so soon where rushes grow, they no 
doubt can keep water holes open around them during December, 
but towards March their houses—the ice often at that period 
attaining a thickness of two feet and a-half,—are covered by at 
least two feet of snow. We must suppose that during this 
period they hybernate as it is impossible for them to reach 
the surface from beneath the ice; towards the end of April 
the spring freshets elevate and sweep the ice to the lee side 
of the lake, carrying with it all their houses, relegating them 
back to their summer holes, where they breed and raise their 
young—remaining all summer. Other climates, the warmer 
ones, where he is said to be common, must modify all his habits, 
perhaps his building instincts; but in our Nova Scotia variety, 
we find him almost as marine an animal as the seal, never seek- 
ing the land for choice, save for rest, fairly holding his own as 
the country becomes populous, and getting his dry nest above 
water, by the strictest and most instinctive means. 
Our other constructive mammal, the historical beaver, differs 
