DWELLINGS OF MUSKRAT AND BEAVER—GILPIN. PAPE 
rus, Cape Breton, is one specimen which seems to merit special 
notice. 
The weight of the specimen is 2} lbs. It is an ore of iron, 
called by Dana Magnetite. It very much resembles some of the 
macnetites of Nictaux. It is evidently part of a bed in meta- 
morphic rocks. The rocks of the region where it is said to have 
been found are of lower silurian and pre-silurian age (Archean), 
The specific gravity of the Cape Breton magnetite is... .4.3 
ilar eM GOse! Riviere 2th nels eee ses & wis ce eee Uae 3.6 
OE biomidaon and Extension roeks.. .... 0.0.5. s5.6. 020. 5.0 
The Nictaux and Moose River magnetites are of middle 
silurian age; of Blomidon, post triassic, 
Art. VII.—On THE DWELLINGS OF THE MUSKRAT AND BEAVER OF 
Nova Scotia. By J. BERNARD GILPIN, A.B., M.D., M.R.CS. 
(Read April 11, 1881.) 
THE constructive mammals are very few, throughout the world. 
To say nothing of the burrowers which construct winding holes, 
or galleries by digging beneath the earth, the most part, are con- 
tent for a home with what nature gives them ; a hollow tree, a 
den amongst rocks, or a form hollowed by the possessor itself, 
from the thick grass, is sufficient for their nests, from the strong 
lion down to the timid hare. And so it was from ancient times, 
as the bones of the hon and cave bear wrapt with the gnawed 
relics of their victim, in one stoney mantle, still mark the feast- 
ing spot and home of their all but mythic forms. In opposition 
to this, our Province of Nova Scotia possesses two mammals, 
each of whom construct dome houses, standing in and out the 
water still,in our Alpine lakes, and broken streamlets, and which 
now unseen except by the woodsman, the hunter or Indian, may 
be readily visited and studied by the naturalist and student. I 
have thought the members of the Institute would be interested 
in this paper, in which I have given a few not new facts, but 
facts old enough, but looked at with new eyes and in perhaps 
new combinations of secne and climate. The muskrat, (Fiber 
