PEALE.] 



UPPER GEYSER BASIN GRAND GROUP. 



209 



the foreground of Plate XIX a), which occasionally spouts a few feet. 

 It has a basin 7 by 12 feet, surrounded by beaded geyserite. Its sur- 

 face temperature was 18G°r., and at 13 feet below the surface, 202° F. 

 It 1872 the surface temperature was 199° F., but it was taken near the 

 time of action. During the water period eruption, No. 3 of the Castle, 

 August 20, 1872, Castle Junior was pulsating, seeming to sink when- 

 ever there was a spurt of spray and steam from the Castle. During 

 the steam period, however, Castle Junior was spouting to a height of 

 2 or 3 feet. 



The remainder of the springs in this group are sufficiently described 

 in the table. , 



• GKATJP GROUP. 



The springs included in this group occupy an area of about 24 acres, 

 extending 2,400 feet aloug the east side of the river opposite the Castle 

 Group. The Grand Geyser is about the middle of the group, and is about 

 500 feet back from the river. 



Besides the Grand, Avhich is one of the prominent geysers of the Basin, 

 there are several minor ones besides the Turban, which has attracted 

 considerable attention on account of its handsome crater and its i3rox- 

 imity to the Grand. The located springs are 56 in number, and are 

 situated on a mound of geyserite that in most places slopes gently to- 

 wards the river. At spring ]S!o. 39 (Limekiln), where the mound is 

 steepest, the height above the river is 10 feet. 



Besides the springs enumerated in the table, there are a number of 

 steam vents and holes in the crust. 



The springs are divisible into several clusters. Below the Grand 

 Group, on tlie same side of the river are three springs that I have in- 

 cluded with the Giant Group. They are separated from the lower springs 

 of the Grand Grouj) by a fringe of trees. 



Talle of the Grand Group. 

 [Note. -•When not Bpecified, the temperature is at the surface.] 



Nomher and name. 



Size and depth. 



1 



p< 



a 



o 

 H 



i 



S 



o 

 o 

 s 



a 



o 

 H 



Remarks. 



1 



4 bv 4i feet 



O J". 



1.50 

 177 



a 163 



b 158 



169 





op. 



( In reality a lonp; fissure ex- 



2 









< panded at points into pools 



3 



a, 4i feet long by 4 feet 

 wide. 







( or spiings. 



Fissure of about 15 feet, witn 



two main basins. 

 Large greenish circular pool. 

 Almost extinct greenish pool. 



4 







5 



8 bv 9 foot; 20 feet deep. 



8 by 8 feet; 7 feet deep.. 



Basin 15 by 20 feet; 

 sjjring 15 feet diame- 

 ter. 



Basin 20 feet diameter; 

 flpriiic: 10 feet diame- 

 ter, 12 feet deep. 



18 inches diameter 



) 



6 



102 

 1C8 



154 

 *156 



173 



163 

 tl79 





7 







8 







Greenish white spring, with 

 white and red bordered 

 basin ; it lias two outlets. 



Sputter hole at river con- 

 stantly agitated. 



9 







10 















t)i(^ watiT rises niid ('.•ills reg- 

 ularly, llowiug iiil () t lie, river. 

 Spouts also a foot or two in 

 splashes. 



11 feet below the surface. 



t When spouting. 



14 H, PT II 



