Map of the Vicinity of the Golden Gate San Francisco Bay California

An early map of the San Francisco Bay.

This quaint geological map of San Francisco Bay was published by the United States Coast Survey in 1856 as part of a report by W.P. Blake on the physical geography of the West Coast. The city of San Francisco had been officially chartered just six years earlier, shortly after California’s admission as a state. Shading identifies different types of geologic formations while a variety of features are labeled throughout the image. Of particular interest are the Presidio, Mission, and Alcatraz Island. The last would be first used as a military prison in 1859.