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Rocher river, the outlet of Athabaska lake, has an average width of about
150 yards and an easy current. A small rapid occurs on it about 10 miles above
the mouth of the Peace, but presents no difficulty to steamboats or canoes, except
in extreme low water, when a-portage frequently has to be made even with canoes.

Slave river after receiving the Peace becomes a broad and deep stream from
one-third to two-thirds mile in width and has a current which runs at a uniform
rate of about 3 miles an hour. To the head of the rapids at Fitzgerald or Smith
Landing, a distance of 71 miles, the river flows between low wooded banks where
solid rock outcrops only occasionally. No rapids of consequence occur in this
stretch and no streams of importance enter.

From F itzgerald to Fort Smith, 16 miles, the course of the river is inter-
rupted by a series of dangerous rapids to avoid which a wagon road has been
built on the west bank for the purpose of transporting supplies for the Mackenzie
River district. The rapids have a total fall of 125 feet, instrumentally measured,
and are caused by a gneissic spur from the Laurentian Plateau region which
erosses to the west of the river at this point. In these rapids the river spreads
out to 13 or 2 miles in width and contains many rocky islands. The descent of
the rapids by boat is accomplished on the east side and five or six portages have
to be made, but the course is so intricate and dangerous that it should not be
attempted without the services of a good guide.

The rapids at Fort Smith constitute the head of navigation for steamers
running in’northern Mackenzie waters, which are unobstructed from this point
northward into the Arctic ocean. If locks could be constructed here, permitting
steamers to surmount the rapids, boats leaving the end of the railway at McMurray
could descend the river to the Arctic ocean, with a run of 1,630 miles.

Slave river below the rapids is a monotonous stream winding through a level
alluvial country, between banks of clay and sand which at Fort Smith are about
100 feet high but become gradually lower northward. The stream has an average
width of about half a mile and a grade of about 6 inches to the mile. The only
important stream entering it is Salt river, a stream about 30 yards wide at the
mouth and draining a considerable tract of country to the west, partly forest
and partly prairie. In places, Slave river meanders widely, forming bends
which are several miles around but -only a few hundred yards across. For
example, at Grand Detour the river flows 15 miles around a big point, the base
of which is about 1,000 yards across, whereas at point Ennuyeux the distance
around is 10 miles and the portage across is only half a mile. s

The banks below Fort Smith are composed entirely of sand or clay and only
at two points do the solid rocks outcrop, namely, at Bell Rock, a massive cliff of
limestone 7 miles below Fort Smith, and on the point below point Vinay cps
‘where beds of gypsum are exposed just at the water’s edge.

Slave river enters Great Slave lake by many channels through a delta of low
alluvial islands, the delta having a spread across the outward side of about 20
miles. An enormous amount of sediment carried by the river is deposited in the
delta which is gradually being built out into the lake threatening to cut off the
eastern and northern arms from the western arm.

Tributaries of Great Slave Lake

The principal streams flowing into the western arm of Great Slave lake are
Little Buffalo, Buffalo, and Hay rivers. These all enter from the south, and on
the north no streams of importance are known.

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