"This cone is a complete ruin. No water issues from it at the present time, and none of the springs in the vicinity are above the ordinary temperature of brook-water; sulphur, alum, and other chemical deposits are abundant. This old ruin is a fine example of the tendency of the cone to close up its summit in its dying stages. The top of the cone is somewhat broken; but it is eighteen feet in diameter at this time, and near the centre there is a hole or chimney two inches in diameter, plainly a steam-vent. This marks the closing history of this spring. The inner portions of this small chimney are lined with white enamel, thickly coated with sulphur, which gives it a sulphur-yellow hue. The base upon which the cone rests varies in thickness. On the east side huge masses have been broken off, exposing a vertical wall twenty feet high, built up of thin horizontal laminæ of limestone. On the west side the wall is not quite as high, perhaps eight or ten feet. It would seem, therefore, that it was at first an overflowing spring, depositing thin horizontal layers until it built up a broad base ten to twenty feet in height; then it gradually became a spouting spring, building up with overlapping layers like the thatch on a house, until it closed itself at the top and ceased." In the tongue that runs down between the junction of the East Fork and the Yellowstone, there is a singular _butte_ cut off from the main range, which at once attracts the traveller's attention. The basis or lower portion of the _butte_ is granite, while the summit is capped with the modern basalt, and the _débris_ on the sides and at the base is remarkable in quantity, and has very much the appearance of an anthracite coal-heap. This _butte_ will always form a conspicuous landmark, not only on account of its position, but also from its peculiar shape and structure. Just below the junction of the East Fork the first and only bridge across the Yellowstone was constructed in 1870 for the accommodation of miners bound for the "diggings" on Clark's Fork. It was a work of considerable boldness, as the river is some two hundred feet wide, and flows with great rapidity over its narrow and rocky channel. A short distance above the bridge, on the west side of the Yellowstone, is a splendid exhibition of black micaceous gneiss, forming a vertical wall on the right side of a little creek, while on the left the entire mass of the hills for miles in extent is composed of the usual igneous rocks. Through these rocks the stream, now not more than four feet wide and six inches deep, has cut a channel from two hundred to four hundred yards wide, through the hardest rocks to a depth varying from five hundred to a thousand feet!