Lava Beds National Monument Butte is just outside the boundary of the monument, the Callahan flow is in Lava Beds and is the youngest flow in the monument. Spatter cones are built out of thicker lava. The lava is thrown out of the vent and builds, layer by layer, a chimney surrounding the vent. Fleener Chimneys and Black Crater are examples of spatter cones. Roughly ninety percent of the lava in the Lava Beds Monument is basaltic. There are primarily two kinds of basaltic lava flows: pahoehoe and 'a'a. Pahoehoe is smooth, often ropy and is the most common type of lava in Lava
Fort Rock lack the heavy metal signature residues of space objects. Crack in the Ground and Fossil Lake are two more nearby Ice Age geological features. South Ice Cave is a lava tube. Derrick Cave is estimated to be long, perhaps Oregon's third-longest lava tube cave. Devil's Garden Lava Field and East Lava Field are other geological oddities northeast of Fort Rock a few miles. Inflated lava, kīpuka, and lava ponds are found here, plus both ʻaʻā and pāhoehoe flows. Fort Rock Valley Historical Homestead Museum and the small community of Fort Rock are one mile south of Fort Rock State Natural