La Pointe Chegoimegon.—A sketch of these islands, as given in the Narrative, denotes that their number is greatly underrated, and will serve to show the configuration of a very marked part of the Superior coast. It must, hereafter, become one of the principal harbors and anchoring-ground for vessels of the lake.
Valley of the St. Louis River.—The St. Louis River takes its rise on the southern side of the Hauteur des Terres, being the same formation of the drift and erratic block stratum which gives origin, at a more westerly point, to the Mississippi. Its tributaries lie northwest of the Rainy Lakes. Vermilion Lake, a well-known point of Indian trade, is a tributary to its volume, which is large, and its outlet rushes with a great impetus to the lake. At what height its sources lie above Lake Superior, we can only conjecture. It was estimated to have a fall of two hundred and nine feet to the head of the Portage aux Coteaux, and may have a similar rise above.
By far its most distinguishing feature is its passage at the Grand Portage through the Cabotian Mountains. We entered it at Fond du Lac and pursued up its channel through alluvial grounds, in which it winds with a deep channel about nineteen or twenty miles to the foot of its first rapids. This point was found one mile above the station of the American Fur Company's trading-house. Here we encountered the first rock stratum, in the shape of our old geological acquaintance, the old red sandstone of Lake Superior. It was succeeded in the first sixteen miles, in the course of which the river is estimated to fall two hundred feet—most of it in the first twenty-nine miles—by trap, argillite, and grauwacke. Through these barriers the water forces its way, producing a series of rapids and falls which the observer often beholds with amazement. The river is continually in a foam for nine miles, and the wonder is that such a furious and heavy volume of water should not have prostrated everything before it. The sandstone, grauwacke, and the argillite, the latter of which stands on its edges, have opposed but a feeble barrier; but the trap species, resisting with the firmness, as it has the color of cast-iron, stand in masses which threaten the life and safety of everything which may be hurled against them. I found a loose specimen of sulphuret of lead and some common quartz in place in the slate rock, a vein of clorite slate, and a locality of coarse graphite, to reward my search.
The Portage aux Coteaux, which is over the basetting edges of the argillite, will give a lively idea of the effects of this rock upon the feet of the loaded voyageurs.
The sandstone is last seen near the Galley on the Nine Mile Portage. Above the Knife Portage, some eight miles higher, vast black boulders of hornblendic and basaltic blocks, are more frequent; and these masses are observed to be more angular in their shapes than the boulders and blocks of kindred character encountered on the shores of Lakes Superior and Huron. There is a vast sphagnous formation, which spreads westwardly from the head of the Coteau Portage, and gives rise to the remote tributaries of Milles lac and Rum River. Much of this consists of what the Indians term muskeeg, or elastic bog. Hurricanes and tempests have made fearful inroads upon areas of its timber, and it is seldom crossed, even by the Indians. This tract lies east of the summit of sand-hills and drift, which environ Sandy Lake, the Komtaguma of the Chippewas. The portage of the Savanna River, a tributary of the St. Louis, is the route pursued by persons with canoes; there is no other species of water craft adapted to this navigation. But wherever crossed, this swamp-land tract imposes labor and toil which are of no ordinary cast. It is the equivalent of the argillite which has been broken down and disintegrated, forming beds of clay soil which are impervious to the water, and we way regard this ancient slate formation of the true source of the St. Lawrence tributaries, as the remote origin of those extensive beds of an argillaceous kind, which exist at many places in the lower lakes and plains.
Immediately west of the Savanna Portage, the Komtaguma summit is reached. This summit consists wholly of arid pebble and boulder drift of the elder period. It exhibits evidences of broken-down amygdaloids, which not only furnish a part of its pebbles, but also of the contents of this stratum, in numerous agates and other subspecies of the quartz family which are found scattered over the surface. This is, in fact, the origin of that extensive diffusion of these species, which is found in the valley of the Upper Mississippi, as at Lake Pepin, &c., and which has even been traced, in small pieces, as low as St. Louis and Herculaneum in Missouri.[ [227] We may conclude that the ancient sandstones, slates, and rubblestone, and amygdaloids, of which traces still remain, were swept from the summit of the Mississippi by those ancient floods which appear to have diffused the boulder drift from the North.
Sandy Lake.—The first view of this body of water was obtained from one of those eminences situated at the influx of the west Savanna River.
This lake is bounded, on its western borders, by the delta of the Mississippi; its outlet is about two miles in length. We here first beheld the object of our search. The soil on its banks is of the richest alluvial character. From this point, dense forests and a moderately elevated soil, varying from three or four to fifteen feet, confined the view, on either side, during more than two days' march. On the third day after leaving Sandy Lake, at an early hour, we reached the Falls of Pakágama. Here the rock strata show themselves for the first time on the Mississippi, in a prominent ledge of quartz rock of a gray color. Through this formation the Mississippi, here narrowed to less than half its width, forces a passage. The fall of its level in about fifty rods may be sixteen or eighteen feet. There is no cascade or leap, properly so called, but a foaming channel of extraordinary velocity, which it is alike impossible to ascend or descend with any species of water craft. It lies in the shape of an elbow. We made the portage on the north side.
Pakágama Summit.—The observer, when he has surmounted the summit, immediately enters on a theatre of savannas, level to the eye, and elevated but little above the water. Vistas of grass, reeds, and aquatic plants spread in every direction. On these grassy plains the river winds about, doubling and redoubling on itself, and increasing its cord of distance in a ratio which, by the most moderate computation, would seem extravagant. On those plateaux, and the small rivers and lakes connected with them, the wild rice reaches the highest state of perfection.
Our men toiled with their paddles till the third day, through this unparalleled maze of water and plants, when we reached the summit of the Upper Red Cedar or Cass Lake, where we encamped. In this distance no rock strata appeared, nor any formation other than a jutting ridge of sand, or an alluvial plain. Plateau on plateau had, indeed, carried us from one level or basin to another, like a pair of steps, till we had reached our extreme height.