GEOLOGICAL SURVEY OF THE TEREITOEIES. 183 



cisterns, with beautifully incrusted siliceous basins, containing water 

 whose tint was an exquisite blue. One of these, whose basin was 

 incrusted with successive ridges, along each of which there was a line 

 of the colors of the speclrum, we called the Prismatic Spring. The 

 majority of them, were simply siliceous springs. A few, however, were 

 chalybeate. The siliceous sinter, (geyserite,) which was very abundant, 

 contained a trace of lime, iron, and magnesia. In some of the springs 

 of low temperature there was a leathery -like organic material of a red 

 color. The following day we moved our camp nearer the center of the 

 basin, about two and a half miles farther south. On our way we passed 

 between two conical, isolated, trachytic hills. The space between our 

 two camps is filled for the most part by the sinter, and where there is 

 none the ground is marshy. A small stream flowed past our camp con- 

 veying the water from the springs to the river. Immediately in front 

 of our camp, about eight hundred yards distant, was the second group, 

 composed principally of geysers. They occupied an area of about three- 

 quarters of a mile. We recorded here the temperatures of sixteen springs, 

 one-half of which were over 190^ F. The lowest was 140° F., and the 

 highest I960 ji\^ the average being 183^ F. The temperature of the air 

 was about 55^ P. to QiP F. One of the geysers, from the peculiar noise it 

 made, was called the Thud Geyser. Th^re were many of them that 

 threw the w^ater from 5 to 10 feet high. In the cool, frosty morn- 

 ing the basin resembled some manufacturing center, as clouds of steam 

 could be seen in all directions. The principal geyser of this group 

 was situated on the slope of a small hill, and was about 20 feet in diam- 

 eter. The rim is about 5 feet wide and 5 feet high. It is composed of 

 geyserite of a grayish color, and is full of deep pockets, which contain 

 balls of gej'serite about the size of walnuts, each one being covered with 

 little rosette-like formations. The column of water thrown out by this 

 geyser during its eruptions is very wide, and reaches the height of 50 

 feet. Near it w^e obtain ed some pieces of wood, which were coated with 

 geyserite of a delicate pink tiuge. The silica had thoroughly pene- 

 trated the woody fiber. We found, also, some pine-cones, coated in the 

 same manner, forming beautiful specimens. A few yards back of the 

 geyser were three large mud-springs, in one of which the mud was red, 

 in another white, and in the third pink. They were all in agitation, 

 and the jets of steam escaping caused the mud to assume the form of 

 small conical points throughout the basins. They were situated in a bed 

 of clay, the red color being due to iron. Below these latter there were 

 some chalybeate springs, the bright-red iron deposit of which had spread 

 over a considerable area and formed a glaring contrast with the white 

 color of the siliceous material. About three-quarters of a mile to the 

 southeast of this group is the third group, situated at the northwestern 

 base of a spur of the mountains, and extending up a ravine a distance of 

 one thousand yards. They occupied a space of about five hundred yards 

 in width. One of the springs from its shape we named the Fissure Spring. 

 We found here three sulphur springs, the only ones in the region. The 

 amount of sulphur present, however, was not very great; their tempera- 

 tures were respectively 138° F., 154o F., and 19Go F. In this ravine we 

 took the temperatures of twenty spriu gs, averaging 158^ F. ; the lowest was 

 130^ F., and the highest 19Go F. About the center of the group was a 

 small lake GOO feet long and 150 feet wide, near the eastern shore of which 

 there was a geyser, which spouted very regularly to the height of 15 or 

 20 feet. A short distance southeast of the lake we found an iron-si)ring, 

 which was surrounded by an abundant deposit j its temperature was ItJU^ 

 F. West of the lake were two geyser-cones, about 18 inches high and 



