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Steptoe and Kamiak Buttes, Whitman County

Washington State Geological Attractions and Destinations


These two quartzite outliers of Idaho's Coeur d'Alene Mountains are islands of older rock surrounded by much younger lava flows, that is, steptoes. (more below)
An eponymic type example
Photo courtesy Robert Ashworth of Flickr under Creative Commons license
Steptoe Butte, shown here, is the type example of a steptoe, an old upland that has been surrounded by younger lava flows. (Because his name was given to the butte, Lt. Col. Edward Steptoe qualifies as a geologic eponym.) In Italy, similar landforms around Etna volcano are called dagalas. Both are varieties of kipuka, the Hawaiian word for an "island" of older land surrounded by lava. Steptoe Butte is a state park and Kamiak Butte is a county park. The views from their peaks are expansive. Both are registered as a National Natural Landmark.

You might imagine that these steptoes preserved the plants and animals on them from harm as lava flooded the surrounding countryside. But likely the hills caught fire, and if they didn't the intense heat would have sterilized them.

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