Distribution of Volcanic Rocks of Devils Postpile and Vicinity
- Undifferentiated surface deposits, including: pumice, stream deposits, recent organic soils.
- Basalt of the Red Cones. Unglaciated red cinder Cones and lava flows.
- Basalt of the Devils Postpile. Dark gray, fine-grained basalt flow, with abundant feldspar crystals.
- Andesite of Mammoth Pass. Light gray to dark gray, fine-grained andesite, with minor feldspar and pyroxene crystals.
- Rhyodacite of Rainbow Falls. Light gray, fine-grained rhyodacite, with minor oxyhornblende crystals. Exhibits horizontal to semi-horizontal platy weathering fractures. Some dense, black, columnar-jointed outcrops.
- Tuff of Reds Meadow. Similar to Bishop Tuff. Buff, ash-flow rhyolite exhibiting welding of pumice with abundant quartz, feldspar, and rock fragments.
- Basalt of The Buttresses. Dark gray basalt, with abundant olivine crystals, and minor pyroxene. Crude columnar jointing.
- Contact, as mapped by Clow and Collum (1983).
- Contact, volcanic units as mapped by Huber and Rinehart (1965; 1967).
- - Monument boundary.