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Gnarl Ridge lava flows from about 350 ka at base to 200 ka at top, ...

Detailed Description

Northward view of Lamberson Butte, the summit of Gnarl Ridge on east flank, which is composed of two sequences of andesite lava flows. Flows at base are about 350,000 years old; those forming middle to upper part of ridge are about 200,000 years old. Newton Creek is at base of ridge in foreground; total relief is about 1,000 feet (300 meters).