force’s Falls, the river makes a descent of about two hundred and fifty feet
into a chasm, whose walls consist of light-red felspathose sandstone, belonging
most probably to the old red sandstone formation, or that which lies under
coal, and occasionally alternates with transition rocks.
The gneiss formation appears a short distance above these falls, producing
hills precisely similar in character to those about Fort Enterprise. After quitting
Hood’s River, and ascending out of the valley through whieh it flows, we
entered upon an even clayey and very barren country, interspersed with shallow
lakes. This plain continued nearly to Craycroft’s River, when the gneiss
re-appeared, presenting the genuine barren ground hills and precipices, together
with their vegetable associates, cenomyce rangiferina, cetraria nivalis, cucul-
lata and islandica, conucularia ochrileuca,4ufourea arctka, arbutus alpinu, rhododendron
lapponicum, and empetrum nigrum, plants which seem to characterize
the Barren Grounds. This formation continues without any essential change
of aspect, but with some occasional differences in the altitude of its hills, until
it unites with the Fort Enterprise district at Obstruction Rapid, between Providence
and Point Lakes. Its hills assume the form of ranges in the neighbourhood
of Congecathewachaga and Rum Lakes.- It is to be observed, however,
that we travelled over this district when the ground was deeply covered-with
snow; and when circumstances were not favourable either for observing or
recording the appearances of the rocks, with sufficient accuracy for drawing
up a geognostical account of them at a future period.
We shall now proceed to offer a few
CONCLUDING REMARKS.
T he observations of Werner, Humboldt, Von Bueh, Saussure, Ebel, and
Daubuisspn, in many districts in the continent of Europe and in America, and
by Jameson in Scotland, shew that the general direction of the primitive and
transition strata, is nearly from N.E. to S.W. It is, therefore, interesting' to
find, that the general result of my notes on the positions of these rocks which
we traced (except in a few instances when our route lay to the westward of
their boundary) through twelve degrees of latitude, also gives N.E. and S.W.
as the average direction of their strata.
The strata of the two classes of rocks just mentioned, were always more or
less inclined to the horizon, the mean angle considerably exceeding 45°.
Their dip was sometimes to the east, sometimes to the west.
These rocks exhibited the same varieties of structure, that they do in other
extensive tracts of country. In general, the slaty structure was parallel to the
direction of the strata, as in gneiss, mica-slate, clay-slate, &c. When the waved
structure made its appearance, it was sometimes conformable with the sèams
■ of stratification, as was very often noticed in the transition clay-slate of the
Copper-Mine River; or it was entirely independent of these, and then it was
very irregular in its direction. The apparently-confused arrangements of structure
of clay-slate and other slaty rocks, more particularly observed at the magnetic
islet in Knee Lake, and on Point Lake, proved, on a more extended and
accurate examination, to be caused by the arrangement of the mass of strata into
variously-formed distinct concretions, in many of which the direction of the slaty
structure was under very different angles, and in very different directions. In
short, in these apparently-disturbed strata we had, though on a great scale, the
same beautiful arrangement that occurs in the rock named by Werner, “ Topaz
Rock.” Independent of these various structures observable in individual strata,
we remarked that the strata themselves, whatever their structure might be,
werè either variously waved or quite straight in their direction.
The general forms, connexions, and distributions of the mountains, hills, and
plains, in the tracts we traversed, and of the cliffs on the coast of the Arctic Sea,
were nearly the same that geologists have remarked as characterizing similar
rocks, similarly circumstanced in other quarters of the-globe.
Granite with sienite, gneiss, mica-slate, and clay-slate, which some geologists
consider to be the predominating primitive rocks, occur in all their usual relations
; of these the gneiss appears to be the most extensively distributed on our
track, and to be always attended with a very scanty vegetation. Granite is the
next in frequency (then mica-slate, and the least abundant are the clay-slate and
protogine. Thé-granite is generally of a red colour, and varies from coarse to
small granular. The loose blocks of stone, which crown the summits of almost
all the hills in the Barren Grounds; aré generally of this latter variety.
Of the gneiss there are two varieties, the one red and the other grey. . The
mica-slate, clay-slate, and' sienite, present the common varieties.. The protogine
granite,, of which' there is . considerable abundance in Slave River,-and
in some other quarters, appears to belong to the mica-slate formation-.- ;