A History of Oil Production in California
Oil from natural seeps was found and refined by California Indians, who used it for many purposes. In the middle 1800s, settlers arriving in California found the seeps and developed the oil on a much larger scale. Eventually asphal-tum deposits were mined, tunnels were dug uphill into oil reservoirs, and wells were drilled — first in onshore areas and then offshore in the Pacific Ocean. By the turn of the Twentieth Century, California was producing about one quarter of the oil in the United States. Today, 100 years later, California stands as the fourth largest oil producing state in the country.