150 



DYNAMICAL GEOLOGY. 



vents builds up moundlike, hivelike, and chimneylike 

 forms (Fig. 79). The silica-charged waters, trickling 



FIG. 79. Crater of Castle Geyser, Yellowstone Park. 



slowly over the mounds, give rise hy deposit to patterns 

 of exquisite and delicate beauty, compared by Hayden to 

 embroidered lace-work with edging-fringe and pendent 

 tassels, and studded with pearls. Similar deposits are 

 formed also in ISTew Zealand ; we give an example in Fig. 

 80. Only a few of the grandest of these geysers can be 

 mentioned : 



1. The Grand Geyser throws up a column of water six 

 feet in diameter to the height of 200 feet, while the steam 

 ascends 1,000 feet or more. The eruption is repeated 

 every thirty-two hours, and lasts twenty minutes. 



2. The Giant (Fig. 81) throws a column five feet in 

 diameter 140 feet in the air, and plays continuously for 

 three hours. 



3. The Giantess, the greatest of all, throws up a huge 



