Oil well pumping unit, south area of the La Honda oil field, CA

The south area of the La Honda oil field, California, was discovered during the late 1950s and produced an estimated 595,000 barrels of oil from about 12 wells, including the well in this photo. Most of the oil was produced from an unusual fossiliferous limestone of Miocene age, informally named the Burns sand, that overlies a thick sequence of Oligocene and Miocene volcanic rocks known as the Mindego Basalt. This image shows the pump unit on the Burns 9 well, which produced oil from the Burns sand at depths of about 1,200 to 1,315 feet. Standing near the well are two U.S. Geological Survey geologists, Bob McLaughlin (far left) and Les Magoon. Kneeling at the well head is an oil field technician named Chris.