Columnar Basalt (1991)

Basaltic lava from volcanic eruptions sometimes forms hexagonal columns as it cools. Erosion eventually crumbles and collapses the columns into oddly-shaped boulders. The Sheepeater Cliffs in Yellowstone National Park, Wyoming, is one of a relatively few places in the world with impressive basalt columns. You can see similar columns at Devils Postpile National Monument in the volcanic Mammoth Lakes area of California.

BACK Yellowstone page Home