largest of the turbid springs has a basin with a nearly circular rim twenty feet from the margin to the water, and forty feet in diameter. There are two or three centres of ebullition; temperature, 188°." A couple of miles above these springs, near the banks of the Yellowstone, is a not less remarkable group of sulphur and mud springs. All the intermediate space abounds in the remains of similar springs, now quiescent or dead, yet giving evidence of former power and activity beyond that displayed by any now existing. "There were giants in those days!" Mr. Langford describes a group of these "unsightly caldrons," varying in size from two to ten feet in diameter; their surfaces from three to eight feet below the level of the plain: "The contents of the most of them were of the consistency of thick paint, which they greatly resembled, some being yellow, others pink, and others dark brown. This semi-fluid was boiling at a fearful rate, much after the fashion of a hasty-pudding in the last stages of completion. The bubbles, often two feet in height, would explode with a puff, emitting at each time a villainous smell of sulphuretted vapor. Springs six and eight feet in diameter, but four feet asunder, presented distinct phenomenal characteristics. There was no connection between them, above or below. The sediment varied in color, and not unfrequently there would be an inequality of five feet in their surfaces. Each, seemingly, was supplied with a separate force. They were embraced within a radius of 1,200 feet, which was covered with a strong incrustation, the various vents in which emitted streams of heated vapor. Our silver watches, and other metallic articles, assumed a dark leaden hue. The atmosphere was filled with sulphurous gases, and the river opposite our camp was impregnated with the mineral bases of adjacent springs. At the base of adjacent foot-hills we found three springs of boiling mud, the largest of which, forty feet in diameter, encircled by an elevated rim of solid tufa, resembles an immense caldron. The seething, bubbling contents, covered with steam, are five feet below the rim. The disgusting appearance of this spring is scarcely atoned for by the wonder with which it fills the beholder. The other two springs, much smaller, but presenting the same general features, are located near a large sulphur spring of milder temperature, but too hot for bathing. On the brow of an adjacent hillock, amid the green pines, heated vapor issues in scorching jets from several craters and fissures. Passing over the hill, we struck a small stream of perfectly transparent water flowing from a cavern, the roof of which tapers back to the water, which is boiling furiously, at a distance of twenty feet from the mouth, and is ejected through it in uniform jets of great force. The sides and entrance of the cavern are covered with soft, green sediment, which renders the rock on which it is deposited as soft and pliable as putty.