238 EEPORT UNITED STATES GEOLOGICAL SURVEY. 



a is a cone or mound from a foot to 18 inches in height, with an orifice 

 measuring 8 by 10 inches. The basin is yellow-lined and about 6 inches 

 deep. The cone is covered with pearly beads of geyserite. When exam- 

 ined it was quiet, and had a temperature of 163° F. 



h is an oblong mound 4 by 11 feet, with greenish tinted water, which 

 bubbles constantly on the sides and at the western end with periods of 

 increased violence. At this end its mound or crater is 2 feet above the 

 general level, while at the opposite end it is only about a foot in height. 

 The average depth of the basin is about 7 feet, except at the deep or 

 western end. There is considerable overflow from this basin. The run 

 is pointed and scalloped, lined with yellow, and projects slightly over 

 the basin. The following temperatures were taken : 



op. 



Surface ,.. 188 



5 feet below the surface 199 



8 feet below tbe surface 201 



10 feet below the surface 202^ 



12 feet below the surface 204 



c. This is the most important mound. It is oblong, with a circumfer- 

 ence of 25 feet at the base, and measures 5 by 5 feet on top. It has a 

 cone at one end with a height of 2J feet, and at the opposite end is a 

 little less than 2 feet above the general level. It is a white beaded mass 

 of geyserite, in which the orifice is a yellow-lined beaded diamond-shaped 

 opening, in which the water was spouting and sputtering all the time 

 during our examination. At intervals the water spurted to a foot or twer 

 above the top of the cone. The following temperatures were taken: 

 Surface, 180° F. ; 6 feet below the surface, during boiling period, 203° F. 

 The action in this cone appeared to be entirely independentof that in &. 



The following are Professor Comstock's notes made in 1873 : 



Another geyser (c), very near, spouted at 6.33 p. m., ceasing wholly at 6.35. This 

 had a similar orifice and chimney, not quite as high as the preceding, but the column 

 of water was of nearly the same dimensions. A third geyser (6), with little or no 

 raised walls, but with a fair-sized pool, but a few feet from the others, spurted at 6.37 

 for a few minutes, throwing the liquid about 60 feet into the air.* 



These, which are the only observations of the height that are recorded^ 

 prove the Trinity Geysers to be of considerable importance. The action 

 was synchronous with the action of the Niobe Geyser, which was not the 

 case when we saw the latter in action in 1878. 



Niobe Geyser. — This geyser, as I have already indicated, is included 

 with the Trinity Geysers by Professor Comstock. It is an irregular, flat- 

 topped cone, 4 feet in height, having a circumference of 46 feet at the 

 base, and measures 5 feet in diameter on top. The orifice is 18 inches 

 by 2^ feet. The outside of the crater is covered with white beaded gey- 

 serite, and the throat of the orifice is lined with yellow, pearly -topped, 

 bead-like masses. It is situated on the same platform with the Trinity 

 Geysers, from which it is separated by a slight depression. The dis- 

 tance between them is about 50 feet. Whenever seen the water in the 

 l^iobe Geyser was in constant ebullition, spurting occasionally above 

 the top of the cone. The water appeared to bulge from one side. The 

 depth of the basin is about 5 feet. The following temperatures were 

 obtained: Surface, 199° F.j 4 feet below the surface, 199° F. 



Professor Comstock saw it in action in 1873. He says : 



We had left the vicinity of the Grand Geyser late in the afternoon of August 25, and 

 "were hastening to our camp at the upper end of the basin, when we were startled by 

 the eruption of another geyser at the edge of a broad terrace just above us. This 

 began at 6.30 p. m., continuing till 6.35.5 p. m. The water proceeded from a mound 



* Reconnaissance of Northwestern Wyoming, by Capt. W. A. Jones, in 1873, p. 254. 



