This extraordinary region was first made known in a way in 1807. A hunter named Coulter visited it, and getting safely back to civilization, he told such wonderful stories of the hot springs and geysers that the unbelieving borderers, in derision, called it "Coulter's Hell." Others visited it subsequently, but their remarkable tales were generally regarded as romances. The first thorough exploration was made by Prof. Hayden's scientific party for the Government in 1871, and his report led Congress to reserve it as a public Park. The visitor generally first enters the Park at the Mammoth Hot Springs, which are near the northern verge of the broad central plateau. Here are the wonderful terraces built up by the earlier calcareous deposits of these Springs, covering an area of several square miles, and in the present active operations about two hundred acres, with a dozen or more terraces, and some seventy flowing springs, the temperature of the water rising to 165°. The lower terrace extends to the edge of the gorge of Gardiner River, with high mountain peaks beyond. The hotel is built on one of the terraces, with yawning caves and the craters of extinct geysers at several places in front. The higher terraces rise in white, streaked with brown and other tints, as the overflowing, trickling waters may have colored them. The best idea that can be got of this place is by conjuring up the popular impression of the infernal regions with an ample stock of heat and brimstone. For a long distance, rising from the top of the gorge of Gardiner River westward in successive terraces to a height of a thousand feet above the stream, the entire surface is underlaid with sulphur, subterranean fires, boiling water and steam, which make their way out in many places. The earth has been cracked by the heat into fissures, within which the waters can be heard boiling and running down below, and everything on the surface which can be, is burnt up. Almost every crevice exudes steam and hot water; sulphur hangs in stalactites from the caves; and in some places the odors are nearly overpowering. It is no wonder the Indians avoided this forbidding region, and that the tales told by the early explorers were disbelieved. Yet it is as attractive as it is startling. The hot springs form shallow pools, where the waters run daintily over their rim-like edges, trickling down upon terrace after terrace, forming the most beautiful shapes of columns, towers and coral decorations from the lime deposits, and painting them with delicious coloring in red, brown, green, yellow, blue and pink. So long as the waters run, this decoration continues, but when the flow ceases, the atmosphere turns everything white, and the more delicate formations crumble. The whole of this massive structure has been built up by ages of the steady though minute deposits of the waters, the rate being estimated at about one-sixteenth of an inch in four days. The rocks upon which