The cinder cones of Hippo Butte, Three Sisters, Juniper Butte, and Crescent Butte are all older than the Mammoth and Modoc Crater flows, more than 30,000-40,000 years old. Eagle Nest Butte and Bearpaw Butte are 114,000 years old. Schonchin Butte cinder cone and the andesitic flow from its base were formed around 62,000 years ago. The flow that formed Valentine Cave erupted 10,850 years ago. An eruption that formed The Castles is younger than the Mammoth Crater flows. Even younger were eruptions from Fleener Chimneys, such as the Devil's Homestead flow, 10,500 years ago, and Black Crater 3,025 years ago. About 1,110 years ago, plus or minus 60 years, the Callahan flow was produced by an eruption from Cinder Butte. Though Cinder Butte is just outside the boundary of the monument, the Callahan flow is in Lava Beds and is the youngest flow in the monument.