The Geology of Crater Lake National Park, Oregon With a reconnaissance of the Cascade Range southward to Mount Shasta by Howell Williams
The Glaciation of Mount Mazama
Evidence of Glaciation Outside the Caldera
Glaciers of Mount Scott
The presence of glacial striae on the caldera rim at Sentinel Rock and west of Cloudcap, and of morainic mounds beneath pumice on the summit of Anderson Bluffs, shows that the glaciers of Mount Mazama once swept round the southern base of Mount Scott. This parasitic cone formed another center of ice dispersal. Down the east slopes of the cone two glaciers, between 4 and 5 miles long, followed the canyon of Scott Creek and the unnamed canyon to the north, as far as the basalt plateau. The cluster of dacite domes at the east base of Mount Scott was formed after these glaciers had retreated. But even after the glaciers had shrunk until they no longer covered the present east rim of the caldera, ice lingered in the cool recesses of the cirque on the northwest side of Mount Scott. At the mouth of this small cirque and on its southwest side one may still see well preserved moraines. If a glacier remained in the cirque when the great pumice explosions took place, it can have been no more than a few hundred yards long.