The Mammoth Paint Pots, a little way east of the Fountain, are probably the most prominent example of this class of phenomena in the Park.
The Great Fountain Geyser lies a mile and a half south-east of the Fountain. It is the chief wonder of the Lower Basin, and, in some respects, the most remarkable geyser in the Park. Its formation is quite unlike that of any other. At first sight the visitor is tempted to believe that some one has here placed a vast pedestal upon which to erect a monument. It is a broad, circular table about two feet high, composed entirely of hard siliceous deposit. In its surface are numerous pools molded and ornamented in a manner quite unapproached, at least on so large a scale, in any other part of the Park. In the center of the pedestal, where the monument ought to stand, is a large irregular pool of great depth, full of hot water, forming, to all appearances, a lovely quiescent spring. At times of eruption, the contents of this spring are hurled bodily upward to a height sometimes reaching 100 feet. The torrent of water which follows the prodigious down-pouring upon the face of the pedestal, flows away in all directions over the white geyserite plain. No visitor to the Yellowstone can afford to miss the Great Fountain Geyser.
In this vicinity are several of the handsomest springs in the Park. One in particular lies just across the hot stream which flows a little to the south of the Great Fountain. It is shaped like an egg set endwise in the ground with the upper part of the shell broken off. It is an exquisite trifle.
In a small valley, extending to the north-east from the Great Fountain, are several objects worthy of notice. One of these is an immense hot lake, by far the largest in the Park. Steady Geyser and Young Hopeful, near the head of the valley, are not remarkable in this land of geysers.
The principal attraction of the locality is what has come to be called the Firehole. It is at the extreme upper end of the valley, difficult to find, and unsatisfactory to visit when the wind agitates the water surface. It is a large hot spring from the bottom of which, to all appearances, a light colored flame is constantly issuing, only to be extinguished in the water before it reaches the surface. At times it has a distinct ruddy tinge and it always flickers back and forth like the lambent flame of a torch. When seen under favorable conditions, the illusion is perfect, and the beholder is sure that he has at last caught a glimpse of the hidden fires which produce the weird phenomena of this region. But it is only illusion. Through a fissure in the rock gas or superheated steam escapes and divides the water, just as bubbles do on a smaller scale. The reflection from the surface thus formed accounts for the appearance, which is intensified by the black background formed by the sides and bottom of the pool.
The Lower Geyser Basin has an area of thirty square miles. Conspicuous among its topographical features are the Twin Buttes, two prominent peaks west of the river which dominate the entire basin. A little way south of these is Fairy Fall, a pretty cascade 250 feet high.
There will be included in this chapter, as more properly belonging to it than to the next, a description of the Midway Geyser Basin. Its principal interest lies in the stupendous character of its phenomena.
Terry Engr. Co.
Haynes, Photo., St. Paul.