As already noticed, the country about the mouth of Gardiner's River is desolate and gloomy. The hill-slopes are covered with sage brush, the constant sign of arid soil, and grass is scarce. This is the first poor camping-place on the route. The cañon being impassable, the trail passes to the right, crossing several high mountain-spurs, over which the way is much obstructed by fallen timber, and reaching at last a high rolling plateau. This elevated tract is about thirty miles in extent, with a general declivity to the north. Its surface is an undulating prairie, dotted with groves of pine and aspen. Numerous lakes are scattered throughout its whole extent, and great numbers of springs, which flow down the slopes, are lost in the volume of the Yellowstone. The river breaks through this plateau in a winding cañon over 2,000 feet in depth—the middle cañon of the Yellowstone rolling over volcanic boulders in some places, and in others forming still pools of seemingly fathomless depth. At one point it dashes to and fro, lashed to a white foam on its rocky bed; at another, where a deep basin occurs in the channel, it subsides into a crystal mirror. Numerous small cascades are seen tumbling from the rocky walls at different points and the river appears from the lofty summits a mere ribbon of foam in the immeasurable distance below. Standing on the brink of the chasm the heavy roaring of the imprisoned river comes to the ear only in a sort of hollow, hungry growl, scarcely audible from the depths. Lofty pines on the bank of the stream "dwindle to shrubs in dizziness of distance." Everything beneath, says Lieut. Doane, has a weird and deceptive appearance. The water does not look like water, but like oil. Numerous fish-hawks are seen busily plying their vocation, sailing high above the waters, and yet a thousand feet below the spectator. In the clefts of the rocks down, hundreds of feet down, bald eagles have their eyries, from which one can see them swooping still farther into the depths to rob the ospreys of their hard-earned trout. It is grand, gloomy, and terrible; a solitude peopled with fantastic ideas; an empire of shadows and of turmoil.
The plateau formation is of lava, generally in horizontal layers, as it cooled in a surface flow, yet upheaved in many places into wave-like undulations. Occasionally granite shafts protrude through the strata, forming landmarks of picturesque form. Like dark icebergs stranded in an ocean of green, they rise high above the tops of the trees in wooded districts, or stand out grim and solid on the grassy expanse of the prairies.
EXTINCT GEYSER, EAST FORK OF THE YELLOWSTONE.
Near the head of the Third Cañon a stream flows into the Yellowstone from the northeast, bearing the sonorous title, Hell-Roaring River. It is quite a large stream, rising high among the mountains, and flowing with tremendous impetuosity down the deep gorges. The mountains on either side come close down to the channel of the Yellowstone, and are among the most rugged in this rugged region. A huge peak of this sort, composed of stratified gneiss, with deep strata of massive red and grey granite, stands at the mouth of Hell-Roaring River, and takes to itself the same imposing name. A short distance above the mouth of Hell Roaring River, the East Fork of the Yellowstone comes in from the southeast. Its sources are high up among the most rugged and inaccessible portions of the basaltic range, several jagged peaks which rise from 10,000 to 11,000 feet above the sea.
"The summits of these high peaks," observes Mr. Hayden, "are all close, compact trachyte, while all around the sides are built up walls of stratified conglomerate. It is plain that all of them are the nuclei of old volcanoes. The trachyte may sometimes be concealed by the conglomerates, but I am inclined to think that each one has formed a centre of effusion. Large quantities of silicified wood are found among the conglomerates, mostly inclosed in the volcanic cement, evidently thrown out of the active craters with the fragments of basalt. My impression is, that when the old volcanoes disgorged their contents into the great lake of waters around, they threw out also portions from the sedimentary formations, and thus the silicified wood comes from the Tertiary or Cretaceous beds, which may have formed the upper part of the walls of the crater. At any rate, these woods belong to the Coal Series of the West, and they are scattered profusely among the conglomerates. Interlaced among the massive beds of volcanic conglomerates are some layers of a light-grey or whitish sandy clay, which show that the whole breccia or conglomerates, with the intercalated layers of clay or sand, were deposited in water like any sedimentary water rocks."
Interesting ruins of ancient springs abound in this valley. Mr. Hayden describes one, a very curious mammiform mound of calcareous deposit, about forty feet high, built up by overlapping layers like those of Liberty Cap on Gardiner's River.
"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."