Page:Popular Science Monthly Volume 12.djvu/424

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THE POPULAR SCIENCE MONTHLY.

Iceland is an elevated plateau about two thousand feet high, with a narrow marginal habitable region sloping gently to the sea. The elevated plateau is the seat of every species of volcanic action, viz., lava-eruptions, solfataras, mud-volcanoes, hot springs, and geysers.

Fig. 1.—Geyser near the Giant, showing the Ornamental Character of the Border (after Hayden).

These last exist in great numbers; more than one hundred are found in a circle of two miles diameter. One of these, the Great Geyser, has long attracted attention.

The Great Geyser is a basin or pool fifty-six feet in diameter, on the top of a mound thirty feet high. From the bottom of the basin