184 GEOLOGICAL SUEVEY OF THE TEEEITOEIES. 



12 inches across at their bases. Erom the top of these the water emerged. 

 They were incrusted with a cauliflower-like foimatioD, and near them 

 in a fissure we obtained balls of geyserite coated in the same manner. 

 The stream flowing from the lake is well filled with a luxuriant growth 

 of Confervoidea. 



About a thousand yards farther south is the fourth group. The 

 ravine in which they are situated is about a mile and a half long and 

 thyee hundred yards wide. Of the many springs and geysers which it 

 contains, we took the temperature of forty-two, varying from 112° F. to 

 198° F. The average temperature was 179° F., the temperature of the 

 air being about 60° F. Just before entering the ravine we passed by a 

 large cone about 25 feet in height, from the top of which steam was 

 escaping. It is probably a geyser, although during our stay it did not 

 have an eruption. At the mouth of the ravine we found the principal 

 geyser of the group. Its basin was circular and about GO feet in diame- 

 ter, although the spring itself, which is in the center, is only about 15 

 or 20 feet in diameter. The incrusted margin is full of sinuses, filled 

 with hot water, which falls into them whenever the geyser is in opera- 

 tion. These pockets contain, also, smooth, rounded pebbles of geyserite, 

 varying in size from that of a pea to a large-sized walnut. They have 

 been rounded by the action of the water. The water in the spring of 

 the geyser was of a blue color and constantly in agitation, though 

 more violently so just before spouting. The column of water projected 

 reaches the height of 100 feet, and is accompanied by immense clouds 

 of steam. Near the upper end of the ravine was a spring, about which 

 the deposit, instead of being white, was black. In some of the springs 

 we found butterflies which had fallen in and been scalded to death, and 

 on taking them out we found them coated with silica, thus commencing 

 to undergo petrifaction. 



About a thousand yards west of our camp, on the banks of the Fire- 

 Hole Eiver, was the fifth group, the largest of all, covering a space of 

 nearly a square mile, and comprising a large number of springs and 

 geysers. We recorded the temperature of ninety-five, more than one- 

 half of which were over 180° F. They varied from 112° F. to 196° F., 

 the average being 172° F. ; the air at the time of observation was 70° 

 F. One of the springs, from its resemblance to a shell, we named the 

 Gonch Spring. One geyser resembled a fortress with numerous port- 

 holes, looking toward the river. Its temperature was 190° F. In the 

 river were several small islands containing geysers. Opposite one of 

 them, on the edge of the river, was a horn-like geyser-cone, which we 

 named the Horn Greyser. Another we called the Cavern. There are 

 also a number of fumaroles, or vent-holes, from which steam constantly 

 escapes. I^ear the northern end of the group the river flows close to 

 the base of a small wooded hill, along the edge of which were some 

 mud-springs and mud-geysers, the mud varying in color, being white 

 in some and blue in others. In some it was very thick, and in others 

 almost as thin as water. On ascending the hill after passing through 

 the woods, we came to a dozen or more interesting mud-springs. They 

 were alnjost all situated at the bottom of large funnel-shaped craters, 

 of about 20 feet diameter at their mouths. ' Tlie mud in most of them 

 was very thick and of a white or grayish color, and the steam in escap- 

 ing did so with a dull, thud-like noise, throwing back the mud in forms 

 resembling the leaves of a lily. Near these there were some small mud- 

 cones, from the top of which there was steam escaping. Breaking 

 them open, they were found to have veins of sulphur and iron running 

 through them. About two miles southwest of the last-mentioned group 



