The springs have their source somewhere within an active volcanic belt, and thus heated by internal fires they pour out their waters at a temperature of 112° to 163° Fahrenheit, which, acting upon the soft limestone, dissolves and converts it into what geologists call travertine, a semi-crystalline deposit that quickly hardens upon coming in contact with the air. When first observed, the terraces resemble a snow-bank, but by other writers they have been compared to the terminal front of a glacier, and again like a foaming cascade suddenly turned into stone. Streaks and patches of red, yellow and green seen upon the white slopes mark the course of overflowing water, while clouds of steam float lightly upward from the many springs, but only to quickly disappear.
There are in all eight well-defined benches, each with a more or less level surface, and terminating with vertical fronts to the next terrace below. Near the terraces, though on a bench of ground by itself, is Liberty Cap, a pillar forty-three feet high and twenty feet in diameter, with sphinx-like profile, the cone of a hot spring long since extinct. Close-by is a similar monolith, not so tall, called the Devil’s Thumb, a name readily suggested by the proximity of the springs to Pluto’s dominion, as some will have it, and the gossip that Satan’s hand is in all the region thereabout.
In wandering around the terraces the visitor is sure to have his surprise quickened by the brightly-tinted basins, and the red and orange slopes overflowed by the hot waters. These colors are due to the presence of minute algæ, or water-plants, whose life is strangely enough supported by the hot water and the lime held in solution; for investigation has disclosed the astonishing fact that the chief work of these microscopic plants is the separation from the water of the carbonate of lime, which they cause by abstracting the carbonic acid.
The view from these mammoth terraces is picturesque beyond comparison: The dark and lofty summit of Sepulchre Mountain shows its drowsy head near-by on the north; while the upper valley of the Yellowstone, and the jagged peaks of Snowy Range, are seen to the northeast, between Sepulchre and the long face of Mount Evarts. In the southeast the eye dwells pleasantly upon the distant view of Lava Creek and Undine Falls, with many snow-white peaks, standing like sentinels around this wizard realm; while Bunsen Peak keeps watch towards the south, its dark slopes making an effective background to the white hills of hot spring deposit.
COATING SPRING TERRACE.—This terrace affords perhaps a better example of the formation of these beautiful monuments of Nature than any of the others. The water is seen flowing gently over the succession of steps, and depositing the calcareous substances of which they are composed. The ground-work is snow-white, but reflected from this is every shade of scarlet, green and yellow, as brilliant as the brightest of our aniline dyes. The spectacle is dazzlingly beautiful, producing a scene that cannot perhaps be equaled elsewhere in the whole world.
ECHO CAÑON FALLS, IN ROCKY MOUNTAINS, NEAR MIDVALE, MONTANA.