THE LIBERTY CAP.
Near the upper terrace, which is really an old rim, are a number of these extinct, oblong geysers, some of which have been broken down so as to show them to be mere shells or caverns, now the abode of wild animals. Dr. Hayden attempted to enter one of them, and found it full of sticks and bones which had been carried in by wild beasts; and swarms of bats flitted to and fro. Some of the mounds have been worn away so that sections are exposed, showing the great number and thickness of the overlapping layers of sediment. Many mounds are overgrown with pine-trees, which must be at least eighty or a hundred years old. Indeed, the upper part of this mountain appears like a magnificent ruin of a once flourishing village of these unique structures, now fast decomposing, yet beautiful and instructive in their decay. One may now study the layers of deposit, sometimes thousands on a single mound, as he would the rings of growth in a tree. How long a period is required to form one of these mounds, or to build up its beautiful structure, there is no data for determining. On the middle terrace, where the principal portion of the active springs are, some of the pine-trees are buried in sediment apparently to the depth of six or eight feet. All of them are dead at the present time. There is, however, evidence enough around the springs to show that the mineral-water is precipitated with great rapidity. It is probable that all the deposits in the immediate vicinity of the active springs are constantly changing from the margin of the river to the top of the White Mountain and return. The deposits upon the summit are extensive, though now there is very little water issuing from the springs there, and that is of low temperature. Quantities of steam are ever ascending from the springs, and on damp mornings the entire slope of the mountain is enveloped in clouds of vapor.
"But," observes Dr. Hayden, in summing up his account of this indescribable locality, "it is to the wonderful variety of exquisitely delicate colors that this picture owes the main part of its attractiveness. The little orifices from which the hot water issues are beautifully enamelled with the porcelain-like lining, and around the edges a layer of sulphur is precipitated. As the water flows along the valley, it lays down in its course a pavement more beautiful and elaborate in its adornment than art has ever yet conceived. The sulphur and the iron, with the green microscopic vegetation, tint the whole with an illumination of which no decoration-painter has ever dreamed. From the sides of the oblong mound, which is here from 30 to 50 feet high, the water has oozed out at different points, forming small groups of the semicircular, step-like basins.
"Again, if we look at the principal group of springs from the high mound above the middle terrace, we can see the same variety of brilliant coloring. The wonderful transparency of the water surpasses anything of the kind I have ever seen in any other portion of the world. The sky, with the smallest cloud that flits across it, is reflected in its clear depths, and the ultramarine colors, more vivid than the sea, are greatly heightened by the constant gentle vibrations. One can look down into the clear depths and see, with perfect distinctness, the minutest ornament on the inner sides of the basins; and the exquisite beauty of the coloring and the variety of forms baffle any attempt to portray them, either with pen or pencil. And then, too, around the borders of these springs, especially those of rather low temperature, and on the sides and bottoms of the numerous little channels of the streams that flow from these springs, there is a striking variety of the most vivid colors. I can only compare them to our most brilliant aniline dyes—various shades of red, from the brightest scarlet to a bright rose tint; also yellow, from deep-bright sulphur, through all the shades, to light cream-color. There are also various shades of green, from the peculiar vegetation. These springs are also filled with minute vegetable forms, which under the microscope prove to be diatoms, among which Dr. Billings discovers Palmella and Oscillara. There are also in the little streams that flow from the boiling springs great quantities of a fibrous, silky substance, apparently vegetable, which vibrates at the slightest movement of the water, and has the appearance of the finest quality of cashmere wool. When the waters are still these silken masses become incrusted with lime, the delicate vegetable threads disappear, and a fibrous, spongy mass remains, like delicate snow-white coral."
The antiquity of these springs is a question of great interest, yet difficult of solution. When were these immense deposits begun? On the margin of the mountain, high above the present position of the hot springs, is a bed of white, or yellowish white limestone, from fifty to a hundred and fifty feet thick. It is regularly stratified and the jointing is complete. There is a belt a mile long and one fourth of a mile wide, covered with cubical masses of this rock that have fallen down the slope of the mountain. These immense blocks, fifty to one hundred feet in each dimension, appear as if the mass had slowly fallen down as the underlying rocks were worn away. So thickly is this belt covered with these huge masses that it is with the greatest difficulty one can walk across it. It would seem that this bed must at one time have extended over a portion or all of the valley of Gardiner's River. Much of the rock is very compact, and would make beautiful building-stone, on account of its close texture and color, and it could be converted into the whitest of lime. If the rocks are examined, however, over a considerable area, they are found to possess all the varieties of structure of a hot-spring deposit. Some portions are quite spongy, and decompose readily; others are made up of very thin laminæ, regular or wavy; enough to show the origin of the deposit without a doubt. But in what manner was it formed? Dr. Hayden believes that the limestone was precipitated in the bottom of a lake, which was filled with hot-springs, much as the calcareous matter is laid down in the bottom of the ocean at the present time. Indeed, portions of the rock do not differ materially from the recent limestones now forming in the vicinity of the West India Islands. The deposit was evidently laid down on a nearly level surface, with a moderately uniform thickness, and the strata are horizontal. Since this group of strata was formed, the country has been elevated, and the valley of Gardiner's River has been carved out, so that the commencement of the period of activity of these springs must date back to a period merging on, but just prior to, the present geological period—probably at the time of the greatest action of the volcanic forces in this region.
Classed with reference to their chemical constituents, the springs here and elsewhere in the Yellowstone Valley are of two kinds: those in which lime predominates, and those in which silica is most abundant. The springs of Gardiner's River are mainly the former. Where does the lime come from? The geology of the country surrounding the springs shows already that there is underneath the spring deposits, at least a thickness of 1,500 feet, of carboniferous limestone; and if the origin of the heat which so elevates the temperature of the waters of these springs is as deep seated as is generally supposed, the heated waters have ample time and space for dissolving the calcareous rocks through which they flow.
CHAPTER VI.
GARDINER'S RIVER TO GRAND CAÑON.