The red pipe stone, I consider, will take its place amongst minerals, as an interesting subject of itself; and the “Côteau des Prairies” will become hereafter an important theme for geologists; not only from the fact that this is the only known locality of that mineral, but from other phenomena relating to it. The single fact of such a table of quartz, in horizontal strata, resting on this elevated plateau, is of itself (in my opinion) a very interesting subject for investigation; and one which calls upon the scientific world for a correct theory with regard to the time when, and the manner in which, this formation was produced. That it is of a secondary character, and of a sedimentary deposit, seems evident; and that it has withstood the force of the diluvial current, while the great valley of the Missouri, from this very wall of rocks to the Rocky Mountains, has been excavated, and its debris carried to the ocean, there is also not a shadow of doubt; which opinion I confidently advance on the authority of the following remarkable facts: At the base of the wall, and within a few rods of it, and on the very ground where the Indians dig for the red stone, rests a group of five stupendous boulders of gneiss, leaning against each other; the smallest of which is twelve or fifteen feet, and the largest twenty-five feet in diameter, altogether weighing, unquestionably, several hundred tons. These blocks are composed chiefly of felspar and mica, of an exceedingly coarse grain (the felspar often occurring in crystals of an inch in diameter). The surface of these boulders is in every part covered with a grey moss, which gives them an extremely ancient and venerable appearance, and their sides and angles are rounded by attrition, to the shape and character of most other erratic stones, which are found throughout the country. It is under these blocks that the two holes, or ovens are seen, in which, according to the Indian superstition, the two old women, the guardian spirits of the place, reside; of whom I have before spoken. That these five immense blocks, of precisely the same character, and differing materially from all other specimens of boulders which I have seen in the great vallies of the Mississippi and Missouri, should have been hurled some hundreds of miles from their native bed, and lodged in so singular a group on this elevated ridge, is truly matter of surprise for the scientific world, as well as for the poor Indian, whose superstitious veneration of them is such, that not a spear of grass is broken or bent by his feet, within three or four rods of them, where he stops, and in humble supplication, by throwing plugs of tobacco to them, solicits permission to dig and carry away the red stone for his pipes. The surface of these boulders are in every part entire and unscratched by anything; wearing the moss everywhere unbroken, except where I applied the hammer, to obtain some small specimens, which I shall bring away with me.