The Geology and Petrography of Crater Lake National Park, 1902
LAVAS OF MOUNT MAZAMA.a
Unlike the andesites, the basalts are limited to the outer slope of Mount Mazama, and do not approach nearer than about a mile of the crest. None of the basalt flows came from the central vent of Mount Mazama. They all issued from adnate cones upon the lower slopes of that great volcano. The northern part of the area mapped contains the principal basalt masses, which issued from four vents—Timber Crater, Desert Cone, Bald Crater, and Red Cone.