GEOLOGICAL SUEYEY OF THE TERRITORIES. 175 



in which the springs are long extinct has caused it to assume a grayish 

 appearance. The main springs are situated on a terrace about half 

 Avay up the mountain, and cover an almost circular space of about two 

 hundred yards in diameter. The color of the water here is almost in- 

 describable, being the purest azure. From these springs clouds of 

 steam are always rising, and the water is always bubbling and seething 

 in its vast caldron-like basin. The water ilowiDg thence proceeds 

 downward from terrace to terrace, until it reaches the lowest, consider- 

 bly cooled. The springs in the center of the main basin are probably 

 all at the boiling-point, although we were unable to determine their 

 temperatures as they were beyond our reach. The temperature of the 

 hottest we were able to determine was 162^ F. The terrace imme- 

 diately above the main basin is bordered by a long rounded ridge, 

 with a fissure extending its whole length. From this fissure nothing 

 but hot vapors and steam escape. Its interior is lined with beautiful 

 crystals of pure sulphur. The bubbling and gurgling of the water far 

 beneath could be distinctly heard. Back of this ridge were two small 

 geyser-like jets of water, which rose to the height of 3 feet intermit- 

 tently. Farther up the gorge, about 1,000 feet above the level of tho 

 river, we discovered two mound-like formations, the largest of which 

 was about 20 feet in height and 50 feet long by 30 feet wide. The other 

 was only about 5 feet high. From the top of these the water spouted 

 to the height of 4 or 5 feet, each geyser-spout proceeding from a small 

 conical mound about a foot in height and eight inches in diameter at 

 its base. Breaking one of these cones, the tube through which the 

 water came was found to be verj' small, only about a quarter of an inch 

 in diameter, while the remainder of the cone was composed of layer 

 upon layer of sediment deposited by the overflowing water. Near these 

 mounds there is a sulj)hur-spring emitting a considerable quantity of 

 sulphureted hydrogen. On the lower terrace the water has spread out 

 more and formed shallower basins. Here there are also some remark- 

 able formations, high, chimney-like masses of the sediment, composed 

 of layer upon layer, which, in the lapse of time, has become very hard. 

 One of the most curious of these, the Liberty Cap, named from ifs 

 shape, is about 45 feet high and 15 feet thick. It is altogether likely 

 that these have once been veritable spouting geysers, for they are anal- 

 ogous in structure to the smaller active ones found higher up the val- 

 ley. They became so high, however, that the i)ressure of the column 

 of water was too great for the boiling-point to be attained in the depths 

 below. Then the eruptions ceased, and the spring gradually became 

 extinct, leaving these masses stand as monuments of their former 

 power. 



The temperature of the water near the river is 120° F.; in some 

 springs a little higher up, 130° F.; and on the lower terrace, 155° F. 

 Still a little higher there is a boiling spring, 102° F. On the second 

 terrace the temi)erature varies from 142^ F. to lG2o F. On the third or 

 main terrace it is Irom 155o F. to 102o F., and on the next, where the 

 small geysers are, it is from 150° F. to l()2o F. At the two mounds high 

 up tbe valley it is from 142° F. to 143^ F., while in the sulphur spring 

 near them it is only 112° F. The average temperature of the atmos- 

 IDhere was 03° F. The majority of the springs give off sulphureted 

 hydrogen gas, some being more strongly im})regnated than others. The 

 water contains sulphureted hydrogen, sul[)hate of magnesia, and car- 

 bonates of lime, soda, and i)otassa.. Whence do these springs obtain 

 the lime which is so abundant in their composition !? 1 think from the 

 passage of the water through the strata of limestone. Even the igneous 



