Mess Lake Lava Field black young basalt. Its westernmost and southwesternmost ends are flanked by the Mess Creek Escarpment, forming a steep prominent cliff. This cliff exposes several layers of black columnar basaltic lava flows with distal rock fragments and pyroclastic deposits. Eruptions of the young Mess Lake Lava Field basalts cascaded down this steep lava cliff similar to what occurs at the island of Hawaii and covered some of the columnar basalt jointing. Near Mess Lake, inactive hot springs can be found and are most likely associated with the most recent eruptive activity in the Mess Lake Lava Field. Hot springs are closely
Lava Beds National Monument Beds. Aa is formed when pahoehoe cools and loses some of its gases. Aa is rough, sharp, and jagged; an excellent example is the Devils Homestead lava flow, which originated at Fleener Chimneys. Most of the rest of the lava in the monument is andesitic. Pumice, a type of rhyolitic lava, also is found covering the monument; this rained down around 900 years ago during the eruption of Glass Mountain. The flows from Mammoth and Modoc Craters comprise about two-thirds of the lava in the monument. Over 30 separate lava flows located in the park range in age from 2,000,000