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. [Illustration: 271 272] [Illustration: 273 274 275] [Illustration: 276] [Illustration: 277] [33] Most unfortunately for this poor fellow, the other one of his tribe, who travelled with him, and could have borne testimony to the truth of his statements, died of the quinsey on his way home. [34] From the very many excavations recently and anciently made, I could discover that these layers varied very much, in their thickness in different parts; and that in some places they were overlaid with four or five feet of rock, similar to, and in fact a part of, the lower stratum of the wall. [35] In Silliman’s American Journal of Science, Vol. xxxvii., p. 394, will be seen the following analysis of this mineral, made by Dr. Jackson of Boston, one of our best mineralogists and chemists; to whom I sent some specimens for the purpose, and who pronounced it, “_a new mineral compound, not steatite, is harder than gypsum, and softer than carbonate of lime_.” _Chemical Analysis of the Red Pipe Stone_, brought by George Catlin, from the Côteau des Prairies, in 1836: Water 8.4 Silica 48.2 Alumina 28.2 Magnesia 6.0 Carbonate of lime 2.6 Peroxide of iron 5.0 Oxide of manganése 0.6 ————— 99.0 ————— Loss (probably magnesia) 1.0 ————— 100.0 —————