nd on the Stony River; and on several parts of the
Slave River they are separated from the limestone only by the breadth of
the stream. On Great Slave Lake, the Stony Island, on the north-east
side of the mouth of Slave River, is composed of granite, whilst the
limestone strata are exposed at Fort Resolution on the south-west side.

[Sidenote: 1027, 1028] The limestone in this extensive tract is commonly
in thin and nearly horizontal beds, and much of it exactly resembles in
mineralogical characters the dolomite and chert of Lake Winipeg. It is
interstratified with thin beds of soft white marl; and in a few places
with a marly sandstone. Extensive beds of stinkstone also occur, and
many beds of limestone containing fluid bitumen in cavities. The bitumen
is in such quantity, in some quarters, as to flow in streams from
fissures in the rock; and in an extensive district, around Pierre au
Calumet on the Elk River, slaggy mineral pitch fills the crevices in the
soil, and may be collected in large quantities by digging a well.

A calcareous breccia also exists in various places, particularly on the
Slave River. Springs depositing from their waters sulphur, and sulphate
of lime, slightly mixed with sulphate of magnesia, muriate of soda, and
iron, are common and copious. A few miles to the westward of the Slave
River, there is a ridge of hills several miles long, and about two
hundred feet high, having several beds of compact, grayish gypsum
exposed on its sides. From the base of this hill there issue seven or
eight very copious, and many smaller springs, whose waters deposit a
great quantity of very fine muriate of soda by spontaneous evaporation.
The collected rivulets from these springs form a stream which is, at its
junction with the Slave River, sixty yards wide and eight or ten feet
deep.

[Sidenote: 1020 to 1026] The organic remains, in this deposit, according
a list kindly furnished by Mr. Sowerby, consist of _spirifers_,
[Sidenote: 1029 to 1032] one of which is the _spirifer acuta_; several
new _terebratulae_, of which one resembles the _T. resupinata_, a
_cirrus_, some crinoidal remains, and corals.

At the union of Clearwater and Elk Rivers, the limestone beds are
covered to the depth of one hundred and fifty feet with bituminous
shale.

I have stated, that on Slave River this limestone formation succeeds
immediately to primitive rocks, but I am not acquainted with the rocks
that lie to the eastward of it on th