Cinder Cone and the Fantastic Lava Beds lava and has concentric craters at its summit, which have diameters of and . Cinder Cone is comprised by five basaltic andesite and andesite lava flows, and it also has two cinder cone volcanoes, with two scoria cones, the first of which was mostly destroyed by lava flows from its base. Cinder cone volcanoes are typically monogenetic, meaning that they only undergo one eruptive period before ceasing activity forever. These eruptions often consist of the ejection of tephra, though they may also generate lava flows, which often originate from vents near the base rather than the summit of the volcanic
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