208 EEPOET UNITED STATES GEOLOGICAL SUEVEY. 



appears to be a daily eruption of cousiderable magnitude, but the 

 grandest eruptions seem to be separated by longer unknoAvn intervals. 

 It is probable that this is one of the oldest geysers in the Basin, if not 

 in the world, and its future study promises to develop some imi^ortant 

 points. One thing is certain : its age does not interfere with the grandeur 

 of the display when it has one of its characteristic eruptions. 



Seguin speaks of witnessing an eruption of the Castle in 1879 which 

 reached the height of 164 feet.* 



Springs Nos. 1-6 are on a flat area of deposit, about 200 yards from 

 the river, and are separated from it by a line of trees. They are of no 

 special importance. 



Nos. 7-18 are along the edge of the river, north of the mound of the 

 Castle. They are but little above the river level. ]S"o. 10 is a spouter. 

 'No. 17a is a cone ou the river's edge. 



1^0. 16 is a pulsating spring. Besides the main basin, which is 5J by 

 6 feet, there is a minor one with several holes. The craters are of pink- 

 beaded silica. The main basin has two openings, from which the water 

 rises gently at first, and is followed by bulges. It rises and falls at 

 intervals of about 3 minutes. 



Kos. 19-27 are on the mound of the Castle; 19 and 20 are near the 

 river's edge, and are not specially important. 



1^0. 21. Beautiful Blue-crested Spring. — This handsome spring is 150 feet 

 north of the Castle, and has an almost circular basin, measuring 19 feet 

 9 inches by 19 feet 6 inches, bordered by a scalloped rim 6 inches in height, 

 which projects slightly over the basin. The latter slopes to an opening 

 on the southwest side, which measures 14 by 15 feet, and is somewhat 

 funnel-shaped. The depth in this basin is 44^ feet. The water is of an 

 ultramarine hue, which is intense over the deep portion of the basin. 

 Whenever observed, the water was quiet and steaming very gently. 

 There was little or no overflow, but the channel leading from the spring 

 indicates that at times it must be considerable in amount. This channel 

 is of gray, geyserite, lined with yellow and salraon-gfay tints, which are 

 deeper as the spring is left, deep yellows and reds replacing the grays. 

 Words are inadequate to present a picture of the beauty of a spring 

 of this description, for it is only one of the many that may be found in 

 the Upper Basin. The following are the temperatures that have been 

 taken : 



O Ji. 



Surface temperature in 1871 172 



Surface temperature in 1872 180 



Surface temperature in 1878 188 



Temperature 10 feet below the surface in 1878 195 



These temperatures prove that there is a variation in the thermal 

 condition of the spring, and point to the probability that at certain times 

 there may be periods of active ebullition. It probably does not spout, 

 as there is no indication of that fact in the surrounding deposits. 



Springs 22, 23, and 24 are near the base of the Castle platform, on the 

 northwest side. The first two have a common outlet, which is of a 

 beautiful yellow and orange color, lined with bright red. No. 23 has a 

 yellow and white rim, and is a double sx^outer. The temperature in it 

 was 197^°. In 1872 it was recorded as 192°. Back of No. 22 the geyser- 

 ite overhangs the spring. 



No. 24. Castle Junior. — This is a very active boiling spring (shown in 



'' Mr. P. Norris, in his Eeport for 1881, p. 57, mentions two eruptions of the Castle. 

 One occurred October 4, 1^1, at 3 p. m., and reached a height of 75 feet, lasting 25 

 minutes ; the other occurred at 9.45 a. m. on the 6th of October, reached a height of 

 100 feet, and lasted 30 minutes. 



