PEAtE.] SHOSHONE GEYSER BASIN MINUTE MAN GROUP. 261 



700 feet from the Taurus Spring, which is the most northern of the 

 Orion Group. The nearest spring is only about 300 feet from the Taurus. 

 At the north end the group merges into the Little Giant Group. There 

 are over thirty springs in the group, several of which belong to the class 

 of geysers, while others are boiling springs. 



Minute Man Geyser (Plate XXXII). — This geyser was named by Pro- 

 fessor Bradley in 1872. It is about 250 feet east of the creek, situated 

 on a mound of geyserite, at the foot of the hills that stand between the 

 creek and the lake. It has a crater that is very irregular in shape, 

 somewhat like that of Old Faithful in the Upper Basin, on the Fire Hole 

 or Madison Eiver. It is from 3 to 5 feet in height and 46 feet in circum- 

 ference. The throat or opening is 3 by 2J feet, and lined with globular 

 masses of gray and yellowish-gray colors. The basin in this crater is 

 about 8 feet in depth. The outside of the crater is beautifully beaded 

 and the colors grays, buff and white, with pearly-gray beaded basins. 

 The ornamental beadwork extends for a considerable distance beyond 

 the crater. At the base of the crater, between it and the hill, is a beau- 

 tifully ornamented pool, measuring 26 by 10 feet. It has a yellow basin 

 4 feet 4 inches deep. This sometimes spouts, but the interval and 

 height were not determined. Most of the water from the geyser flows 

 into this pool, but I was unable to tell what effect it has upon it. Some- 

 times it remained full of water during the eruiJtion of the Minute Man, and 

 at others it was entirely empty. Professor Bradley's observations in 

 1872 seemed to show that it was emptied by the eruption of the Minute 

 Man. On the top of the crater of the Minute Man are several sulphur- 

 lined vents, which appear to be independent of the geyser. The erup- 

 tions of the Minute Man consist of spurts of water. The main mass of 

 water does not attain a very great elevation. The spurts reached 23 

 feet at the highest, as measured by us from the end of a 50-foot base line. 

 The column or rather mass of water inclines towards the creek. Almost 

 all the water flows back into the pool. None of the observations deter- 

 mined any regularity in the action of the geyser. 



Professor Bradley gives the following description of the eruptions in 

 1872: 



These occur pretty regularly for some hours, at intervals of from 2 to 3 minutes, but 

 gradually decline in force, until the supply of water becomes exhausted. Then the 

 geyser is silent for several hours, until all the crevices, as well as the surface-pools, 

 are again tilled with water, when its eruptions recommence with much violence, the 

 jets then reaching altitudes of from 30 to 40 feet. These again decline, and the series 

 of phenomena is repeated. * 



The following is a transcription of my notes on the geyser: 



August 14. — The Minute Man has sj^outed frequently during the day 

 to a height of 10 or 15 feet, but no time observations have been made. 



August 15. — The geyser was in action this morning, but seems to have 

 been quiet most of the day. 



August 16. — About two hours' observations were made on the Minute 

 Man to-day, while the surrounding springs were being examined. The 

 pool back of the geyser was full of water, and quiet, having a tempera- 

 ture of 177° F., with the air at 61° F. 



The following table gives the eruptions witnessed, with the interval, 

 length, and height of a number of these spurts: 



"Report U. S. Geol. Survey for 1872, p. 246. 



