From introduction: The Red Bluff Bay area was examined briefly for the Geological Survey by John C. Reed and others in 1939. During the summer of 1941 the writers, with R. E. L. Rutledge, mapped this area on a scale of 1:12,000, and examined the serpentine masses in the interior during the course of reconnaissance trips into the surrounding region.

From Introduction: "This publication is a summary of earthquake activity in the United States and the regions under its jurisdiction for the calendar year 1939. A history of the more important shocks of the country appears in Serial 609 of the Bureau, "Earthquake History of the United States: Part I-"Continental United States (Exclusive of California and Western Nevada) and Alaska," and Part II. -"Stronger Earthquakes of California and Western Nevada, Revised (1941) edition."