The Indians who had passed the night near our vessel returned very early, on the 6th of August, to their camp, that they might be able to travel in one day to Fort Mc Kenzie. The night, which was very cool, had passed over quietly, and we had every reason to be satisfied with the behaviour of this numerous band of Indians, for few other tribes would have conducted themselves so peaceably and moderately on a similar occasion. This, it is true, was for their own interest, since they had hitherto been sufferers from the bad reputation which they had among the Whites.
At break of day the weather was extremely cool and disagreeable; the thermometer at half-past seven was only at 58°, and a bleak wind prevailed, which enabled us to use our sails. The part of the country called The Stone Walls, which now opened before us, has nothing like it on the whole course of the Missouri; and we did not leave the deck for a single moment the whole forenoon. Lewis and Clarke have given a short description of this remarkable tract, without, however, knowing the name of Stone Walls, which has since been given it.[60] In this tract of twelve or fifteen miles, the valley of the Missouri has naked, moderately high mountains, rounded above, or extending like ridges, with tufts of low plants here and there, on which the thick strata[61] of whitish coarse-grained friable sand-stone, which extends over all this country, are everywhere visible. As soon as we have passed Judith River this white sand-stone begins to stand out in some places, till we have passed Bighorn River, and entered the narrower valley of the Stone { 236} Walls, where the strata extend, without interruption, far through the country, and lie partly halfway up the mountain, and partly form the summits. They are the continuation of the white sand-stone which occurs in such singular forms at the Blackhills. At all the places which are bare of grass, they are visible, and there we see horizontal or perpendicular angles and ledges resembling walls, some of which contain caverns. This sand-stone formation is the most striking when it forms the tops of more isolated mountains, separated by gentle valleys and ravines. Here, on both sides of the river, the most strange forms are seen, and you may fancy that you see colonnades, small round pillars with large globes or a flat slab at the top, little towers, pulpits, organs with their pipes, old ruins, fortresses, castles, churches, with pointed towers, &c. &c., almost every mountain bearing on its summit some similar structure.