mestone
which occurs in Slave Lake formed a great portion of them; but here a
greenish-gray, and rather dark-coloured, compact limestone, with a flat
conchoidal fracture, replaces it. Variegated-sandstone, and some
purplish, felspathose-sandstone, or compact felspar, also occur pretty
frequently, together with slaty limestone, bituminous-shale,
lydian-stone, pitchstone-porphyry, and various sienites, granites, and
greenstones, almost all porphyritic.

The Rock by the river's side presents the first solid strata that occur
on the immediate banks of the river after passing the Forks. It is a
round bluff hill about five hundred feet high, with a short
obtuse-conical summit. A precipice three hundred feet high, washed by
the river, is composed of strata of limestone, dipping N.W. by W. at an
angle of 70 degrees; but the strata in other parts of the hill have in
appearance the saddle-formed arrangement. [Sidenote: 127] The limestone
is of a blackish-gray colour, slightly crystalline structure, and much
resembles the stone of the principal beds in the hills at the rapid and
mouth of Bear Lake River. Its beds are from one to two feet thick, and
much intersected by small veins of calc-spar. There are also some larger
veins a foot and a half thick, which traverse the strata obliquely,
having their sides lined with calc-spar, and their centres filled with
transparent gypsum. [Sidenote: 128] I observed a small imbedded pebble
of white sandstone in the gypsum. [Sidenote: 127] Some of the beds of
limestone consist of angular distinct concretions. [Sidenotes: 131, 132]
A small island lying off this rock, having its strata dipping south at
an angle of 20 degrees, presents a bed a foot thick, entirely composed
of these angular concretions, covered by a thin-slaty limestone, and
reposing on thicker beds, all of which are dark-coloured. No organic
remains were observed.

A few miles below the "Rock by the river side," a very rugged ridge
appears on the eastern bank. It has sharp craggy summits, and is about
five or six hundred feet high. For nearly sixty miles below this place
the river continues about eight hundred yards wide, bounded by banks
chiefly of clay; but in some places of a clayey shale having a bluish
colour. The banks are in many places one hundred and fifty feet high,
with a beach beneath covered with boulders. A little above the site of
the Old Fort Norman the river dilates, and is full of islands; and a
short way inland