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1956 Map of Joaquin Rocks

Name: 1956 Topographic Map of Joaquin Rocks
Creator: U.S. Geological Survey
Published: 1959
License: https://creativecommons.org/publicdomain/mark/1.0/

USGS Topo · Published 1959

About this map

The rugged western edge of the San Joaquin Valley meets the Diablo Range in this 1950s survey, defined by the sharp geological transition of the Coalinga Anticline. To the east, the flat valley floor is organized by a rigid grid of agricultural avenues and large family-run holdings including Giffen Cantua Ranch, Terry Ranch, and Sunset Farms. This era shows the intensive development of the Coalinga Oil Field and the East Coalinga Extension Oil Field, where numerous wells and tanks mark the landscape of California's petroleum industry.

Contrasting the industrial valley, the western terrain rises into the Joaquin Ridge, home to the prominent Joaquin Rocks and The Clearing. High-elevation landmarks like Black Mtn overlook deep drainages such as Horsethief Canyon and Urruttia Canyon. This map preserves the locations of early water sources vital to the region's development, such as Green Water Spring and Sulphur Spr, alongside remote outposts like the Lillis Ranch.