The Columns That Nearly Became Rubble

About eighty thousand years ago, a lava flow cooled slowly enough for the contraction to organize itself. As the basalt shrank, it cracked along lines of geometric regularity, producing the hexagonal columns you see here now, a sixty-foot wall of stone that looks as though it was built rather than formed.

The process is the same one that creates similar formations in Iceland and at the Giant's Causeway in Ireland: a thick lava body, cooling from the outside in, contracting and fracturing along evenly spaced joints. The columns here are predominantly six-sided, though the geometry varies slightly as you move along the face. After the columns formed, glaciers moved through the valley, polishing the tops of the formation to create the geometric floor at the base that you can walk on, a natural mosaic of cross-sectioned hexagons.

In nineteen ten, a hydroelectric company filed an application to use the formation as rockfill for a dam. The columns would have been dynamited and pushed into the river. John Muir organized opposition to the proposal. President Taft designated Devils Postpile a national monument in nineteen eleven, and the dam was never built.

The formation survived by one year's margin. The nineteen ten application and the nineteen eleven designation are documented in NPS records. There was no certainty that the monument status would hold; at the time, conservation designations were routinely challenged by resource interests. This one held.

Shuttle service from Mammoth Mountain brings most visitors here now. The columns are the same as they were before anyone named them. What is different is the legal status that keeps them in place.