\ 34 river is reduced to a width of about 70 feet between rock walls. The portage trail across the bend is 4 miles in length and runs over a ridge 1,000 feet in height. “Below the Devils portage for 30 or 40 miles the river flows through what is called the Grand canyon, but is more correctly a succession of short canyons, with expanded basins between filled with eddying currents. In low water the whole of this reach can be easily run in almost any kind of a boat, but in the season of high floods . . . . . the water forcing its way through the throat- like contractions is thrown into a commotion too violent for any but the staunchest boats to stand. The canyon is reported, to have been run in two hours, which would be at the rate of about 18 miles'an hour, an astonishing velocity, but the time was probably underestimated.”! The last of the constric- tions in Grand canyon is known as Hell Gate because it forms the entrance from below to the wild portion of the river. Shortly below Hell Gate the Liard breaks through the foothills and enters the Great Central plain, in which it has an uninterrupted flow and presents no obstacles to navigation until near its mouth. Its principal tributaries on the north are ‘Beaver and: South Nahanni rivers, both streams flowing from Mac- kenzie mountains and as yet little known. On the south are Fort Nelson river a comparatively easy-flowing stream from 150 to 200 yards wide at its mouth, and Black river, a smaller stream draining a lake country to the southeast. Below Fort Liard the river flows in a shallow valley often filled with islands and its current runs about 4 miles an hour. Within 30 miles of -the Mackenzie, however, the valley deepens and takes on the appearance of a wide eanyon. The current becomes swift and for nearly 10 miles breaks over a succession of riffles. These are all easily run in a canoe by keeping close to the right bank, but will form a rather serious obstacle to navigation of the river by steamboats. Before joining the Mackenzie the river expands to a width of nearly 2 miles, much of which, however, is occupied by islands and sand-bars. Great Bear River Great Bear river’ carries the water of Great Bear lake to the Mackenzie in a stream about 90 miles in length. It issues from the Jake in a broad, shallow channel with a swift current which it maintains throughout its course. It is confined throughout most of its length between banks of sand or clay and is 150 to 350 yards in width. About half-way down its course it cuts through Franklin mountains and in doing so forms a rapid nearly 8 miles in length. This, however, is easily navigable for canoes in all stages of water by following the right hand shore, but by its shallowness presents considerable difficulties for steamboats. Below the rapid the river expands and its current is not so swift. The water of Great Bear river is beautifully clear and of a greenish-blue colour, particularly noticeable when contrasted with the main stream at its junction. coe Peel River | The sources of Peel river and its upper tributaries lie on the northern and western slopes of Mackenzie mountains. The main stream occupies a great bay -1 McConnell, 'R. G., Geol. Surv., Can., vol. IV, 1888-89, p. 47 D a 2 Bell, J. M., Geol. Surv., Can., vol. XII, pt. C.