122 



GEOLOGICAL SURVEY OF THE TERRITORIES. 



deep down in the 

 all fioislied off 



sides of the basin are what appear 

 with the same delicate work. The 



white silica 

 to he chambers, 



Castle receives its name from its resemblance to the ruins of an old 

 castle as one enters the valley from the east. The silica has crystallized 

 in immense globular masses, like cauliflowers or spongiform corals; al] 

 around it the crystals seemed -to have formed about a nucleus at right 

 angles to the center; the entire mound is about 40 feet high, and the 

 chimney 20 feet ; the lower portion rises in steps formed of thin laminae 

 p. g of silica, mostly very thin, but some- 



^4 — ^ i.^^^,.,:,.™ comi>act, an inch or 



times becoming 



two thick. On the southeast side, 

 where the water is thrown out contin- 

 ually, these steps are ornamented with 

 the usual bead and shell work, with 

 the large cauliflower-like masses, but 

 the other portions are fast going to de- 

 cay, and the debris are abundant; in- 

 deed, this has undoubtedly been one 

 or' the most active and powerful geysers 

 in the basin ; it still keeps up a great 

 roaring inside, and every few moments 

 throws out a column of water to the 



licight of 10 or 



15 feet; all around it 



PEARLY SILICA. 



Fig 



are some most beautifully ornamented 

 reservoirs that receive the surplus wa 

 ters. If I should here describe the Giant, 

 Grotto, Punch-Bowl, and a hundred 

 other geysers of all classes, it would be 

 pretty much a repetition of what has 

 already been written. The Giant has a crater like a broken horn, and, 

 while my party were in the basin, iflayed at one time one hour and 

 twenty minutes, throwing the water up to the height of 110 feet. Lieu- 

 tenant Doane states that at the time of his visit the previous year it 

 played three and a half hours, throwing a column of water 90 to 200 feet. 

 ^'*The Giant has a rugged crater, 10 

 feet in diameter on the outside, with 

 an irregular orifice 5 or G feet in di- 

 ameter. (Fig. 58.) It discharges a vast 

 body of water, and the only time we 

 saw it in eruption the flow of water 

 in a column 5 feet in diameter, and 

 140 feet in vertical height, continued 

 uninterruptedly for nearly three hours. 

 The crater resembles a miniature model 

 of the Coliseum. 



Our search for new wonders leading 

 US across the Fire-Hole Eiver, we as- 

 cended a gentle incrusted slope, and 

 came suddenly upon a large oval aper- 

 ture with scalloped edges, the diam- 

 eters of which were 18 and 25 feet, 

 the sides corrugated and covered 

 with a grayish-white siliceous deposit, which was distinctly visible at 

 the depth of 100 feet below the surface. No water could be discovered, 

 but we could distinctly hear it gurgling and boiling at a great dis- 

 tance below. Suddenly it began to rise, boiling and spluttering, and 



* N. P. Langford in Scribner's Monthly for June, 1S71. 



SPONGIFORM OR CAULIFLOWER SILICA. 



