l, or had a southerly dip. The third ridge
presents, when viewed from the westward, a magnificent precipice,
seemingly about one thousand two hundred feet high, and which extends
for at least fifteen miles. After passing this ridge, the river
inclines to the eastward, and the forms of the hills are less distinctly
seen.

As I could not visit the Rocky Mountains, I know nothing of their
structure except from report. An interpreter in the Hudson's Bay
Company's service, who had travelled over them, informed me that there
are fourteen or fifteen ridges, of which the three easternmost are the
most rugged, those that succeed being broader and more rounded.
[Sidenote: 122] This man gave me a specimen of a pearl-gray semi-opal,
resembling obsidian, brought from the third or fourth ridge. The
natives, by means of fire, cause this stone to break off in thin, flat,
conchoidal fragments, with which they form arrow-heads and knives. The
thin pieces are nearly transparent on the edges. [Sidenote: 123] He also
gave me a specimen of plumbago, from the same quarter, and some specular
iron.

Mr. Macpherson, of the Hudson's Bay Company, in a letter respecting the
Rocky Mountains, near _Fort au Liard_, on the River of the Mountains, or
south branch of the Mackenzie, informs me, that "these mountains may be
traced into somewhat uniform ranges, extending north-westerly and
south-easterly, nearly parallel with the River of the Mountains, and are
in appearance confusedly scattered and broken, rising here and there
into high peaks." [Sidenote: 124, 125] This gentleman had the kindness
to send me specimens of a cherty rock, some of which, he states, were
from the third range westward from the river, and others from a spur
which projects in a southern direction from the fourth range, and rises
about six hundred feet above the adjacent valley. These specimens cannot
be distinguished from those of Limestone Point, on the north shore of
Great Bear Lake[32], Mounts Fitton and Conybeare, two remarkable peaks
which terminate the Eastern range of the Rocky Mountains on the shores
of the Arctic sea, were found by Captain Franklin to consist of
transition rocks, of which an account is given in the subjoined
note.[33]

Sir Alexander Mackenzie, towards the conclusion of the interesting
narrative of his voyages, says, of the Rocky Mountain range, "The last
line of division is, the immense ridge, or succession of ridges of the
stony mountains, whose nort