150 EEPORT UNITED STATES GEOLOGICAL SUEVEY. 



from this spring is lined with very handsome resetted pebbles of gej- 

 serite. Pine cones coated with silica are also seen along its course. 



Ko. 3. This spring is near the foot of the ravine below No. 2, and is a 

 large white and yellowish cavern-like basin in which the water has a blu- 

 ish tint, which is especially dark over the spring proper, for there is both a 

 pool and a spring in the basin, which is very irregular in shape. The 

 water at the spring has a temperature of 196<^ F., and a great quantity 

 of steam escapes from it, obscuring the view. No. 3, a, is simply a retl- 

 lined fissure in the water-way from No. 2, and the water it contains is 

 largely derived from the latter spring. 



No. 4. This is a large spring about 75 by 100 feet, a short distance 

 northwest from the Mud Pufifo. It has a green-lined basin and bubbles 

 in the center. The border of the spring is scalloped. The temperature 

 of 125° F. was taken at the edge. Between this spring and the Mud 

 Puffs there are several steaming mudholes. 



No. 5. is a very active boiling spring at a little higher level than No. 

 1. It is a square-cornered hole in laminated geyersite, measuring 16 

 feet by 9 and 5 feet. The active part is at the narrow end, where there 

 is a constant spouting and boOing. The water here has a temperature 

 of 1980 F. 



No. 6. is the remaining spring on the upper level. It is a small pul- 

 sating spring of reddish, muddy water, with a temperature of 193° F. 

 Between it and No. 5 there is a small hole filled with clear water. 



Besides these springs there are several old cones that mark the former 

 sites of springs. In some of these the deposit has a firm, hard, opaline 

 structure. 



The springs and geysers from No. 7 to No. 16 are on the main geyser 

 mound, which is almOiSt circular in shape, the drainage radiating in all 

 directions but one, and in that we have the higher level on which the 

 Mud Puffs are located. This mound Ijas been called Fountain Terrace, 

 and on its summit is the Fountain Geyser. It is about 80 feet above the 

 general level. Springs 7, 8, and 9, are back of the Fountain Geyser 

 and are unimportant. Old Cone Spring is merely the remnant of what 

 was once probably a geyser. 



No. 10. Fountain Geyser (Fig. 2, Plate VII). — ^The Fountain Gey- 

 ser consists of a spring and a pool separated only by a narrow constric- 

 tion. The spring, which is the geyser proper, is about 30 feet in length 

 by 20 in width. It narrows in the direction of the pool and has rather 

 square comers. It is an opening in laminated geyserite on a broad, 

 table-like mound. This appears to have had a flat surface, the edge of 

 which forms a distinct rim or line around the basin, over which, in most 

 places, it projects a few inches. From beneath this rim the sides slope 

 in somewhat rounded masses, which are distinctly seen when the water 

 is low in the basin, and have a little resemblance to a series of cush- 

 ions around the edge. The rim marks the level at which the water usu- 

 ally stands, and just outside of this, on all sides but one, there is an 

 irregular mound-like mass of beaded geyserite which has been built up by 

 the evaporation of the water that falls during the eruptions. It is from 

 2 to 4 feet in height. In one end of this basin is a cavem-like hole, 

 which is the true geyser, and over which the water is of a beautiful blue 

 tint, like the color of blue-bottle glass. 



The pool of the Fountain, a portion of which is shown in the fore- 

 gronnd of the illustration (Plate VII, fig. 2), is about 120 feet in length 

 and 100 feet in width; an immense quantity of steam rises from it, 

 which obscures the view. It is generally shallow and without a marked 

 rim. It has two basins,, or bowls, however, that are deep. The largest 



