The formations giving the name to this national monument (later upgraded to a national park) are made up of rhyolithic and andesitic rocks going back to an ancient volcano ripped apart by tectonic movements along the San Andreas Fault.
- Location
- View on OpenStreetMap
- Created
- on Friday 5 October 2007 by Martin Mergili
- Keywords
- extinct volcano, mountainscape, volcanic rock, volcanism
- Visits and license
- 4104 visits, CC BY-NC-SA 4.0 DEED license