PEALE.] UPPER GEYSER BASIN OF FIRE HOLE RIVER. 187 



CHAPTER VIII. 



UPPER GEYSER BASIN OF FIRE HOLE RIVER. 



The Upper Geyser Basin of Fire Hole Eiver is the most wonderful of 

 the two, containing as it does the principal geysers whose names are 

 now so well known everywhere. It extends from just below the mouth 

 of the Little Fire Hole Eiver up the main Fire Hole Eiver and Iron 

 Spring Creek, a branch joining the Little Fire Hole just above its 

 mouth. The j)rincipal springs and geysers are on the main stream. As 

 the two streams mentioned approach each other as they flow north, the 

 basin is somewhat triangular in shape. The distance from the Soda 

 Geyser Group to Old Faithful Group is about 2^ miles, and from the 

 latter to the Emerald Group is nearly a mile and a quarter. The entire 

 area of the basin is nearly 4 square miles. The principal geysers are 

 located within a distance of about a mile along the course of the river. 

 The latter flows from southeast to northwest through the basin, and 

 after Iron Spring Creek unites with it the direction is more northerly. 

 The springs appear to add but little to the volume of the river ordi- 

 narily, although some of the geysers are said to have largely increased 

 the river during their periods of action. The temperature of the water, 

 however, is afl'ected by the springs, as the observations made in 1872 

 plainly show. They are the following : 



OF. 



Temuerattire in Fire Hole River above Old Faithful 53 



remperature in Fire Hole River opposite Bee Hive 56 



Temperature in Fire Hole River opposite Grand Geyser 60 



Temperature in Fire Hole River j ust above Giant Geyser 60 



Temperature in Fire Hole River below Grotto Geyser 60 



When the first temperature was taken the air was 5G^, and when the 

 last was taken it was 58°. 



In the tables and maps of the groups described in this chapter 440 

 springs and geysers are enumerated, all of which are located by corres- 

 ponding numbers on the accompanying map. Of these some twenty-six 

 are known to be veritable geysers. The distance from the center of the 

 Lower Geyser Basin to the lower limit of the Upper Basin is about 4 

 miles, while from the Egeria Springs it is only 2 miles. The trail between 

 the two basins used before the road was cut was very marshy and made 

 the trip a very disagreeable one. The Upper Basin is well timbered, and 

 the soil in most places where there are no spring deposits is comijosed 

 of the debris of the volcanic rocks, mainly a black volcanic sand. The 

 suiTounding rocks are rhyolitic, an obsidian mass being usually seen 

 on the top. The first detailed descriptions ot the Upper Basin are those 

 pubhshed by the members of the Doane- Washburn expedition, which 

 have already been so frequently referred to, and the names given to 

 the principal geysers are the ones still retained. They, however, did 

 not witness all in action, and the survey in 1871 named some more. In 

 1878 also we discovered some new geysers, which are now named for the 

 first time in this report. 



In the following i)ages of this chapter the various groups of the Upper 



