Timber Crater - Prominent Geological Features of Crater Lake National Park
In the northeast corner of the park, there is a well preserved shield volcano capped by pyroclastic cones. From the perfection of its form, this volcano may be judged to be among the youngest of the region.
The shield is approximately 5 miles in diameter, and the volume of material erupted approximates 5 cubic miles. The shield is composed essentially of
flows of olivine basalt and basaltic andesite.... [Timber
The Geology of Crater Lake National Park, Oregon (1942) by Howell Williams]
Plate 14. Fig. 1. Timber Crater and the rim
of Crater Lake, from Mount Bailey. (Photograph by Victor Duran.); The Geology of Crater Lake National Park, Oregon (1942) by Howell Williams