Devils Postpile

Devils Postpile

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3 listed

Historical/Interpretive Information/Exhibits, Scenic View/Photo Spot, Trailhead

Approximately 80,000 years ago, a lava flowed from an unknown location upstream from the location of today's monument. As it flowed down the valley, it eventually ran into an obstruction which served as a dam to the lava's path. Pooling up to 400 feet behind the natural dam, the lava cooled. Conditions were such that the lava--that was incredibly uniform in its mineral composition--cooled at a very slow rate. As it cooled, it contracted and cracked, forming hexagonal columns. 65,000 years later, a glacier flowed through the same valley, revealing the sides and tops of the columns. Glacial polish can still be seen today at the top of the formation.