The whole country behind us seemed to have been dug and thrown up into huge piles, as if some giant mason had been there mixing his mortar and paints, and throwing together his rude models for some sublime structure of a colossal city;—with its walls—its domes—its ramparts—its huge porticos and galleries—its castles—its fosses and ditches;—and in the midst of his progress, he had abandoned his works to the destroying hand of time, which had already done much to tumble them down, and deface their noble structure; by jostling them together, with all their vivid colours, into an unsystematic and unintelligible mass of sublime ruins. To this group of clay bluffs, which line the river for many miles in distance, the voyageurs have very appropriately given the name of “the Brick-kilns;” owing to their red appearance, which may be discovered in a clear day at the distance of many leagues. By the action of water, or other power, the country seems to have been graded away; leaving occasionally a solitary mound or bluff, rising in a conical form to the height of two or three hundred feet, generally pointed or rounded at the top, and in some places grouped together in great numbers; some of which having a tabular surface on the top, and covered with a green turf. This fact (as all of those which are horizontal on their tops, and corresponding exactly with the summit level of the wide-spreading prairies in distance) clearly shows, that their present isolated and rounded forms have been produced by the action of waters: which have carried away the intervening earth, and left them in the picturesque shapes in which they are now seen. A similar formation (or _de_formation) may be seen in hundreds of places on the shores of the Missouri river, and the actual progress of the operation by which it is produced; leaving yet for the singularity of this place, the peculiar feature, that nowhere else (to my knowledge) occurs; that the superstratum, forming the tops of these mounds (where they remain high enough to support anything of the original surface) is composed, for the depth of fifteen feet, of red pumice; terminating at its bottom, in a layer of several feet of sedimentary deposite, which is formed into endless conglomerates of basaltic crystals. This strange feature in the country arrests the eye of a traveller suddenly, and as instantly brings him to the conclusion, that he stands in the midst of the ruins of an extinguished volcano.