Just east of Grand Geyser is the Saw-mill, a moderate sized geyser, with three smaller ones by the side of it, all playing at the same time. From the larger a column of water is constantly shot up fifteen or twenty feet, with much the sound of the escape of steam from a pipe. The orifice is not more than six inches in diameter; but with the three smaller ones playing at the same time a great commotion is excited. Near this little group are several large boiling springs, which throw up the water in the centre from two to four feet. These are funnel-shaped, with orifices from six inches to two feet in diameter, in basins with nearly circular rims, from fifteen to forty feet in diameter. About one fourth of a mile northeast of the Castle, upon a mound thirty feet about above the river, built up of thin laminæ of silica, and rounded off, rise four chimneys of different sizes, which are geysers, though perhaps not spouting extensively at present. One is twelve inches high, nearly circular, and three feet in diameter; the second is oblong, four by six feet, with rather coarsely scolloped margins, with an aperture about fifteen inches in diameter; the third chimney is about three feet high and six feet in diameter at the base, with an orifice nearly quadrangular twelve inches across. The spongiform masses inside are covered all over with beautiful pearly beads of silica. The fourth chimney rises five feet above the mound, is ten feet in diameter at the base, with an orifice two feet across, lined inside with the spongiform masses. This has been at one time a first-class geyser, but is now fast going to decay, a beautiful ruin. The elegant bead work on the margin, and all the spongiform masses, now are falling into pieces, forming great quantities of _débris_ around the base of the mound. There is also one boiling spring of great beauty. The orifice, which is nearly circular and beautifully scolloped around the margin, extends straight down, and the water rises within an inch or two of the margin. The water is in a state of constant agitation, boiling up two feet at times. The margin has a coating of bright cream-yellow, while all around the surface there is the most delicate and intricate embroidering, surpassing the most elaborate lace-work. Surrounding the crater is an outer reservoir four feet wide, with a white and reddish-yellow rim, while in the bottom of the reservoir is the variegated sediment which aids in giving such a wonderfully gay appearance to the spring. A stream of water flows from the spring to the river, and the channel is lined for fifty yards with the variegated sediment. Near this is another mound which rises, with laminated steps, about six feet. Dr. Hayden called it the Bathtub. It has much the shape and size of an ordinary bathing-tub, five feet by ten, beautifully scolloped around the inner margin with the spongiform or cauliflower masses of silica, the outer surface being adorned with the greatest profusion of pearly beads. The water is constantly boiling up two feet high, though but a small quantity flows from the spring. The entire valley is full of similar springs, many of these no doubt geysers whose periods of activity have never been observed. "We could not distinguish," writes Lieut. Doane, "the geysers from the other hot springs except by seeing them play, and doubtless there are many besides in the valley of great size, which we saw when quiet, and classed as boiling springs. They all vary in times, force, deposits, and color of water. The number of springs of all kinds in the valley is not less than fifteen hundred; and, with the exception of the Bluestone Springs, scarcely any two are exactly alike. Taken as an aggregate, the Firehole Basin surpasses all the other great wonders of the continent. It produces an effect on the mind of the beholder utterly staggering and overpowering. During the night we were several times awakened by the rush of steam and the hissing of the waters, as the restless geysers spouted forth in the darkness. A constant rumbling, as of machinery in labor, filled the air, which was damp and warm throughout the night."