The Geologic History of the Diamond Lake Area

The impetus for the project to map and describe the geology of the Diamond Lake area must be credited to Vondis E. Miller, Supervisor of the Umpqua National Forest. In the spring of 1963 Mr. Miller contacted Lloyd W. Staples, Head of the Department of Geology, University of Oregon, and the author subsequently was engaged for the project through Dr. Staples.

While working in the Diamond Lake area the author received the cooperation of George E. Reynolds and Donald R. Darling, U. S. Forest Service employees stationed at Diamond Lake during the summer months. These individuals afforded the writer every courtesy and in large measure helped to make the field season an efficient and pleasant one.

Richard Brown and C. Hans Nelson, of the Crater Lake Naturalist's office, provided the author access to the publications available in the Crater Lake National Park Library. The assistance of these individuals is gratefully acknowledged.

Acknowledgment also is due Donald J. Tandy and Richard Platt, District Ranger and Assistant District Ranger, respectively, of the Diamond Lake Ranger District.

The author's chore has been largely one of compilation of scattered bits of geologic information. He can claim little originality for the contents of the report. Information provided by the publications of Howel Williams particularly should be acknowledged. The descriptions contained in his papers titled "The Ancient Volcanoes of Oregon" and "Mt. Thielsen: A Dissected Cascade Volcano" were especially useful. Much of the material contained in those papers appears in altered form in this report. The various publications which were used by the author appear in the bibliography.

The geologic map included in this report (see inside back cover) is based on two maps published by Howel Williams, and contains additions and modifications by the author.