242 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



DESCEIPTION. 



No. 1. Three-Crater Spring and Geyser (Plate XXIV). — This spring 

 derives its name from the fact that there are three basins connected by 

 narrow passages. 



A is the basin at the south end in the foreground of illustration, and 

 is about 12 feet in diameter, having a depth of 5^ feet, at the bottom of 

 which the orifice is about 2 by 3 feet. It is a white basin with an over- 

 hanging raised scalloped edge of grayish-white geyserite. Outside of 

 this the tints are light salmon and salmon-gray. The water has a light 

 bluish tint and bubbles gently at intervals. There appears to be some 

 overflow to the central basin. The surface temperature was 191° F. 

 At 4 feet below the surface it was 195° F. This basin is the one in the 

 foreground of the illustration. There are two or three outlets when the 

 basin is full. 



B. — This is the central basin, and appears to receive water from both 

 the others, for which it acts as a reservoir. The main overflow is from this 

 basin towards the east. It is almost circular, measuring 21 by 26 feet. 

 It is a quiet pool, with a white basin, over the center of which the 

 water has a greenish-blue tint, and a temperature of 187° F., both at 

 the surface and 9 feet below it. The outer edges of the basin are com- 

 posed of laminated and flaky geyserite, inside of which the sides slope 

 into a basin 10 or 11 feet deep. The rim of the basin is grayish white 

 capped with light yellow. 



C. — This is the northern and largest basin of the three. It might be 

 considered as two, a being similar to B; but there is no narrow passage 

 between it and the larger portion of the basin in which &, c, and d are 

 situated. It merely expands beyond a. On the west side it is about 

 a foot high with small basins outside. In this direction there is evi 

 dently considerable overflow at times. The bottom of the basin is flat 

 until the openings are approached, and is of a creamy white color and 

 light saffron, except over the orifices, where it is of a bluish tint. The 

 edge is gray and white with yellow and pink tints on the west. It 

 overhangs on the north side. At this end also the basin is lined with 

 flakes of geyserite. The depth is from 4 to 8 inches, and the tempera- 

 ture 149° F. in the center, a. The main basin about a is 29 feet wide; 

 a itself is 15 by 20 feet and 12 feet deep. It is a quiet blue-tinted 

 hole with two holes in the bottom. Its surface temperature is 162° F. 



1) is towards the west side of the main basin, and is a hole about 5 

 feet deep, over which the water has a deep greenish tint. Around it 

 the basin is light yellowish white. The temperature is 146° F. 



c is a small hole with mottled yellow and white lining and a tempera- 

 ture of 151° F. It is near 6, on the west side of the main basin. 



d. Three-Crater G'eyser. This is towards the east side of the main basin, 

 which here slopes to an orifice of about 2 feet diameter, from which the 

 steam escapes and causes the spouting. The steam appears to escape 

 with great effort, and makes a startling noise that is more like the noise 

 made by a pack of fire-crackers muffled in a box than anything else I 

 can think of. It raises the water in great bulges, splashing in all direc- 

 tions, with thumps. Every now and then a jet is squirted to a height 

 of 15 or 20 feet, but the average is about 5 feet. The water in the main 

 basin G and in B is thrown into waves, with beautiful effect, causing an 

 -oxerflow from the latter. The steam does not appear to heat the water 



