"Great Fountain" Geyser, throwing up clouds of steam and boiling water, Yellowstone Park.
This is one of the famous spectacles of the Lower Geyser Basin. For several acres all around here the ground is like what you see underfoot, covered with a more or less brittle shell of "geyserite", a silica deposit from the overflow of the springs. It is grayish and yellowish in color and here and there it gives way with the "crunching" effect of an ice-crust. The water that you see in the pools is a clear, beautiful blue, its color caused by the presence of a peculiar growth of algae (water plants). The big pool of the geyser yonder is thirty feet across. For two, three, sometimes four hours, ...
(For more, see "View full record.")