The Côteau des Prairies is the dividing ridge between the St. Peters and Missouri rivers; its southern termination or slope is about in the latitude of the Fall of St. Anthony, and it stands equi-distant between the two rivers; its general course bearing two or three degrees West of North for the distance of two or three hundred miles, when it gradually slopes again to the North, throwing out from its base the head-waters and tributaries of the St. Peters, on the East. The Red River, and other streams, which empty into Hudson’s Bay, on the North; La Riviere Jaque and several other tributaries to the Missouri, on the West; and the Red Cedar, the Ioway and the Des Moines, on the South.
This wonderful feature, which is several hundred miles in length, and varying from fifty to a hundred in width, is, perhaps, the noblest mound of its kind in the world; it gradually and gracefully rises on each side, by swell after swell, without tree, or bush or rock (save what are to be seen in the vicinity of the Pipe Stone Quarry), and everywhere covered with green grass, affording the traveller, from its highest elevations, the most unbounded and sublime views——of nothing at all——save the blue and boundless ocean of prairies that lie beneath and all around him, vanishing into azure in the distance without a speck or spot to break their softness.
The direction of this ridge, I consider, pretty clearly establishes the course of the diluvial current in this region, and the erratic stones which are distributed along its base, I attribute to an origin several hundred miles North West from the Côteau. I have not myself traced the Côteau to its highest points, nor to its Northern extremity; but it has been a subject, on which I have closely questioned a number of traders, who have traversed every mile of it with their carts, and from thence to Lake Winnepeg on the North, who uniformly tell me, that there is no range of primitive rocks to be crossed in travelling the whole distance, which is one connected and continuous prairie.
The top and sides of the Côteau are everywhere strewed over the surface with granitic sand and pebbles, which, together with the fact of the five boulders resting at the Pipe Stone Quarry, shew clearly that every part of the ridge has been subject to the action of these currents, which could not have run counter to it, without having disfigured or deranged its beautiful symmetry.
The glazed or polished surface of the quartz rocks at the Pipe Stone Quarry, I consider a very interesting subject, and one which will excite hereafter a variety of theories, as to the manner in which it has been produced, and the causes which have led to such singular results. The quartz is of a close grain, and exceedingly hard, eliciting the most brilliant spark from steel; and in most places, where exposed to the sun and the air, has a high polish on its surface, entirely beyond any results which could have been produced by diluvial action, being perfectly glazed as if by ignition. I was not sufficiently particular in my examinations to ascertain whether any parts of the surface of these rocks under the ground, and not exposed to the action of the air, were thus affected, which would afford an important argument in forming a correct theory with regard to it; and it may also be a fact of similar importance, that this polish does not extend over the whole wall or area; but is distributed over it in parts and sections, often disappearing suddenly, and reappearing again, even where the character and exposure of the rock is the same and unbroken. In general, the parts and points most projecting and exposed, bear the highest polish, which would naturally be the case whether it was produced by ignition, or by the action of the air and sun. It would seem almost an impossibility, that the air passing these projections for a series of centuries, could have produced so high a polish on so hard a substance; and it seems equally unaccountable, that this effect could have been produced in the other way, in the total absence of all igneous matter.
I have broken off specimens and brought them home, which certainly bear as high a polish and lustre on the surface, as a piece of melted glass; and then as these rocks have undoubtedly been formed where they now lie, it must be admitted, that this strange effect on their surface has been produced either by the action of the air and sun, or by igneous influence; and if by the latter course, there is no other conclusion we can come to, than that these results are volcanic; that this wall has once formed the side of a crater, and that the Pipe Stone, laving in horizontal strata, is formed of the lava which has issued from it. I am strongly inclined to believe, however, that the former supposition is the correct one; and that the Pipe Stone, which differs from all known specimens of lava, is a new variety of steatite, and will be found to be a subject of great interest and one worthy of a careful analysis.[35]
With such notes and such memorandums on this shorn land, whose quiet and silence are only broken by the winds and the thunders of Heaven, I close my note-book, and we this morning saddle our horses; and after wending our way to the “Thunders’ Nest” and the “Stone-man Medicine,” we shall descend into the valley of the St. Peters, and from that to the regions of civilization; from whence, if I can get there, you will hear of me again. Adieu.
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