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DYNAMICAL GEOLOGY. 



ing heights, from 5 to 40 feet. In 30 minutes, "Fountain " stopped suddenly, and imme- 

 diately the steam-jet began again ; in 20 minutes more, the jet again stopped, and at 

 once a small pool a few yards from "Fountain," which was empty when that was play- 

 ing, but had become partly filled from its overflow, began to boil and throw up water to a 

 height of 5 or 10 feet, and continued this for half an hour ; as it moderated, the steam-jet 

 opened anew, but ceased when the boiling became more violent. The facts, illustrated 

 in other parts of the region, prove a sympathy between different vents. 



28.3. 



Beehive Geyser in action. Holmes. 



On page 152, the agency of plants (Algse) in the deposition of the silica and calcare- 

 ous material of the geysers (first observed by W. H. Weed) is described. 



There is a small geyser region on Sao Miguel, one of the Azores, in the north Atlantic. 

 It is situated in the Val de Furnas, where three centuries since there was a volcanic 



