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.