1848.

ROCK BY THE RIVER'S SIDE.

181

CHAP. VI.

ROCK BY THE RIVER'S SIDE. -SHALE FORMATION. -FORT NORMAN. TERTIARY COAL FORMATION.-LIGNITE BEDS.-FOSSIL LEAVES.-EDIBLE CLAY. SPONTANEOUS COMBUSTION OF THE

RIVER BANK. — HILL AT BEAR LAKE RIVER. -HILL AT THE RAPID ON THAT RIVER. ·FOREST.-PLANTS.-BIRDS.

WE drifted with the stream all night, and in the morning of July the 25th, a thick fog preventing us from pulling, we continued to drift, trusting that the current would carry us clear of shoals and low islands. The sky cleared at breakfast-time, and by noon we were abreast of the "Rock by the River's Side." In some places, where there are islands, the river is two or three miles wide; in others, it does not appear to be more than a mile, or a mile and a half. The small island, which lies in the channel just above the Rock by the River's Side, is composed of blackish-grey compact limestone, dipping to the south-half-east, at an angle of about twenty degrees; the upper bed, which is thinner and more slaty than the others, being composed of irregularly oblong distinct concretions. On the upper or south side of the Rock by the River's Side the stone is a bituminous limestone, yielding the smell of stinkstein when struck: the

precipitous face of the rock appears to be the same kind of limestone. Immediately below the Rock, for the distance of half a mile, limestone similar to that of the small island occurs in gently inclined beds.

In the body of this high bluff the beds are nearly vertical; and, as well as I could judge from the view obtained in descending the stream, they were disposed as if the axis of the ridge had been the direction of the elevating force, the beds inclining towards the summit from both sides. In some parts, there seemed to be inclined beds lying nonconformably over the ends of the nearly vertical ones, but I could not be certain, without closer examination, that what I saw was not merely oblique sections of the edges of the lower beds.

1848.

RIVER TERRACES.

183

A thermal spring, much resembling sea-water in its saline contents, issues from the front of the cliff, and the fissure from whence it flows is incrusted with crystallised gypsum.* Shale beds abut against the lower side of the Rock, covering the limestone beds above mentioned; but they are in a great measure concealed by the shelving debris of the bank. Contiguous to the upper or south side of the Rock there are sloping banks of gravel, capped by a vertical wall of friable sandstone. And three miles higher up the stream, there are two river terraces, more complete than any I noticed elsewhere on the Mackenzie, though in many places a high and low bank can be traced. These terraces are composed of fine sand; and the slope between them is so steep as to require to be ascended on all fours. Both terraces are very are covered with

regular in their outlines, and well grown Pinus banksiana.

The uppermost is

about two hundred and fifty feet above the river. From this terrace, the Rock by the River's Side is clearly seen to be part of a chain, which is crossed there by the river, as has been already mentioned. This is not so evident from the channel of the stream. The high sand-banks continue almost with

* Dr. Davy, who kindly analysed some water from this spring, ascertained that the chief saline ingredient was sulphate of magnesia.

out a break for twenty miles further up, and in some places they are seen to rest upon a grey shale. At one place, where there is a good section, it was perceived that the surface of the shale on which the sand reposed was uneven, and much indented also by pot-holes and projecting tongues; the gravel and sand descending into the pits, and the points of shale rising among the sand. The similarity of these shale and sand-cliffs to those at the junction of the Clear-water and Elk Rivers is very great; but the shale generally is not so bituminous as at the latter locality. The surface of the country above is strewed with gravel and boulders, and in the decay of the bank these fall down and line the channel of the river. When the water is high, as it is in the spring, little flat beach is to be seen; but in the autumn, the pavement of boulders to which I have already alluded is exposed. Among these, above the Rock by the River's Side, I observed a considerable number of granites, some gneiss, many sienites, basalts, and greenstones; also felspar rock, felspar porphyries, Lydian-stones, quartz rock, and limestones of various kinds, with quartzose sandstones, white, red, and spotted.

I have been disposed to give a more full abstract of the notes I made in descending and ascending this part of the river, because, in following its oblique course of more than fifty miles, from the first

1848.

BLACK-WATER RIVER.

185

ridge of the Rocky Mountains at the bend, to the second at the Rock by the River's Side, all the various strata of the valley are seen, and, if properly examined, there is little reason to doubt that a key to the geological formations of the entire length of the Mackenzie might be obtained.

On the left bank, six miles below the Rock by the River's Side, beds of shale appear, having a slight dip to the southward; and the ridge, which is prolonged on that side from the rock abovenamed in a north-north-east direction, appears very rugged, with irregularly serrated summits, the crest being apparently extremely narrow. The country between the ridges seems to be pretty even, except where it is cut by rivulets; and the high bank of the river is level, though in places it looks hummocky or hilly, because of the gullies which intersect it.

In the evening we landed to cook supper at the mouth of Black-water River, which issues from a lake of the same name lying on the eastern bank; and, embarking again to drift during the night, passed a bend of ninety degrees, which the river makes to the westward, and which is known to the voyagers by the appellation of "The Angle " (L'équerre). It marks the passage of the river through another range, of which a high hill on the eastern bank, named Clark's Hill, is the most con