15.5: Natural Resources of the Peninsular Ranges

A Rich Land

Any area as varied as the Peninsular Ranges must have multiple natural resources. Some such as water and precious metals are in relatively short supply, but others such as building materials are abundant. Much of the development of urban centers in the Peninsular Ranges is not only related to the presence of a major harbor and seaport along its coast, but also because the materials necessary to build an urban infrastructure: sand, gravel, and limestone (concrete and cement), oil and gas (energy), sand and asphalt (road building), specialized sand – glass sand (windows), clay (sewer pipe), and gypsum (plaster and drywall) are abundant and many of these commodities are still mined today.

California has a history of prospecting and mining precious metals, and the Peninsular Ranges were actively prospected. While precious metals have been discovered and mined here (gold, silver, nickel, mercury, and tin are examples), most mines have long since played out and the mining of precious metals is mostly just a memory. Gemstones and rare or collectible minerals are still mined. For much of the world, the Peninsular Ranges are still a prime location for tourmaline, kunzite, and other collectible rare minerals and gems.

Water (or Rather the Lack of Potable Water)

One of the key resources necessary for life is water. In the Peninsular Ranges province, as in many areas of southern California, this is the resource that frequently presents the biggest challenges. Drought has been a major influence throughout California's history; 2011-2017 was the longest drought recorded so far, with 2012-2014 as the driest three consecutive years on record. All the counties in the Peninsular Ranges started importing water to meet local needs decades ago – Orange in the 1920s, San Diego in the 1940s, and Riverside in the 1950s. In any given year, San Diego county imports approximately 70% to 90% of its potable water, Orange county imports approximately 50%, and estimates of how much water Riverside county imports vary greatly but are less than either Orange or San Diego counties.

Most of the local water districts are part of the greater Metropolitan Water District of Southern California (MWD) which acts as a regional water wholesaler, managing the sale and disbursement of water from the Colorado River and northern California. Without the purchase of outside water, most of the water districts in Peninsular Ranges would not be able to meet the needs of their resident populations. Depending upon imported water is not the only way local water districts are trying to improve the availability of water. Water conservation is strongly encouraged by all the water districts within the province, but the coastal areas are in a more precarious situation than the inland areas.

The water supply situation, and water rates, for coastal areas are high because of the large amount of imported water needed. Northern Orange county uses a combination of approximately 75% local groundwater and 25% imported water to supply the county’s water needs, augmented by recycling. Southern Orange county imports over 80% of its water. San Diego county has even less water and more people. Because it purchases almost all of its water; its water rates are astronomical compared to most of the country and it has developed a very sophisticated water purchasing system (Video15.5.1).

Video \(\PageIndex{1}\): Where San Diego County Gets Its Water

A detailed overview of the different sources of water in San Diego county and how it manages its purchasing of so much of its water supply.

Therefore these counties have considered options that other areas would consider prohibitively expensive. In Orange county, this is a massive recycling effort, the Groundwater Replenishment System (GWRS), which recycles the water that goes through sewage treatment plants and then uses this recycled water to replenish the groundwater basin and for injection wells to maintain the fluid barrier protecting the aquifer from saltwater intrusion. San Diego county has taken a different approach and instead of massive recycling, it has built a desalination plant, which provides approximately 10% of the county’s water. Desalination is removing the salts from seawater to make it potable.

Fortunately, for Riverside county, there is more available groundwater there than is available in either Orange or San Diego counties. Also, one of the MWD’s newest and largest reservoirs is in Riverside county outside Hemet, CA. Diamond Valley Lake (Figure \(\PageIndex{1}\)), is an off-stream reservoir used to store water from both the Colorado River and the California State Water Project (see Water Infrastructure and Management) in a roughly central location between Los Angeles and San Diego for use during times of drought or other emergencies.

Figure \(\PageIndex{1}\): Diamond Valley Lake, a reservoir in the Metropolitan Water District’s water storage system with the San Jacinto Mountains in the background. "DiamondValleyLakeViewSanJacinto" by Zindor via Wikimedia Commons is licensed under CC BY-SA 4.0.

The Diamond Valley Lake reservoir also has the advantage of being on the Pacific plate. One of the major concerns of the MWD is that all of its outside water sources have either canals or pipelines that cross the San Andreas fault system; having the water storage on this side of the plate boundary helps ameliorate the potential problem of not being able to get water into southern California in the event of a large earthquake. Work on the project started in 1995 and was completed in 2003 and it was one of the largest construction projects in the nation during the 1990s. Full, it provides a 6-month water supply for the MWD and at over 260 billion gallons, holds more water than Lake Havasu on the Colorado River and almost as much water as all of the other reservoirs in southern California combined.

One of the misconceptions about water use in southern California and in the Peninsular Ranges province in particular is that much of the water use is for agriculture. While this is true in eastern Riverside county in areas that are part of the Colorado Desert province, it is not true in western Riverside County or in Orange and San Diego counties. While some farming does still exist, the increasing population and pressure for land for homes and businesses means that agriculture is becoming a smaller and smaller part of the economy. By 2007-2008, only 12 of 31 the water agencies in Orange county reported any agricultural water use. In 2015, agricultural water use was down to only 8% of the county’s water in San Diego county and it is expected to continue to decline. Therefore, more and more of the water supply is now supporting urban populations rather than agriculture.

Precious Metals, Not So Precious Metals, and Oil

California is the Golden State, our state mineral is gold, and gold mining has a long history in the Peninsular Ranges province. Gold has never, however, been as important of a commodity in the Peninsular Ranges as it was and is in the Sierra Nevada or other parts of the state (see Gold of the Sierra Nevada). While gold has been discovered in many parts of the Peninsular Ranges, only two major gold mining districts were in the province – the Julian District in San Diego county and the Pinacate District in Riverside county.

Julian is the more famous and was the more productive of the two. Gold was discovered in 1870, and the mining district was formed that year. A gold rush occurred, with miners flocking to the area to stake claims. Most of the gold mining is within or adjacent to the Julian Schist associated with the Cuyamaca-Laguna Mountains shear zone. Of the nine significant mines in the district, the most productive was the Stonewall Jackson or Stonewall Mine. Approximately 220,000 ounces of gold total was mined in the Julian District, and of that about 45% was from the Stonewall Mine, which produced over $2 million in gold between its discovery in 1870 and closure in 1926. Production in the Julian district as a whole was from 1870 to 1926, with peak production in 1870 to 1880 and 1888 to 1896. The mines are now closed, and Julian today is better known for its annual Apple Days Festival every autumn.

The Pinacate Mining District in Riverside county has a different history; placer gold (see Gold of the Sierra Nevada) was discovered there in 1850, and hard-rock mining did not begin there until 1874 when the Good Hope Mine was developed. The hard-rock mining was mostly native gold in quartz veins in quartz monzonite and quartz diorite/tonalite. Of the seven significant gold mines in the district, approximately 104,000 ounces of gold total was mined, with the Good Hope Mine as the largest producer. The Good Hope was active from 1874 to 1936, and most active and productive from 1889-1894 (Figure \(\PageIndex{2}\)). Today this area of Riverside county is mostly housing developments.

Figure \(\PageIndex{2}\): The main shaft of the Good Hope Mine in 1907, Riverside County, California, with the head frame, tramway to the mill, and the waste dump. Good Hope Mine 1907 from the collection Rob Skinner via Wikimedia Commons is in the public domain.

If gold is number one on the list of sought after precious metals, its sister, silver, is not far behind. San Diego county and the western part of Riverside county within the Peninsular Ranges are not known for silver mining. Orange county however was the home of the Silverado Mining District, and which created quite a stir between 1878 to 1881 but produced very little silver, along with some lead and zinc. Other precious metals and metals mined in the Peninsular Ranges province include mercury, tungsten, tin, and minor amounts of copper and molybdenum. However, most of these ventures were relatively short-lived and frequently were associated with shortages that occurred during either WWI or WWII, and once the war was over, prices dropped, and those mines were no longer economic.

"Black Gold" however is another story. Oil production from the coastal plain of both the Peninsular Ranges and Transverse Ranges provinces began in the late 1800s and continues through to today (Box 15.5.1).

Box \(\PageIndex{1}\): Oil and Gas in the Peninsular Ranges Province

Most of the Peninsular Ranges province has no history of oil discovery or production. Oil fields are not usually found in plutonic igneous rock, which is the major rock type in the province. Oil is usually associated with sedimentary rock, which means the best possibility of finding oil in the province is on the coastal plain.

Just like Riverside county is split between two provinces, the Peninsular Ranges in the west and the Colorado Desert in the east, Orange county is also split between two provinces. The very northernmost part of Orange county is in the Los Angeles Basin of the Transverse Ranges province and that is where almost all of the oil production occurs. So, while Orange county is a major oil producing county in California, most of the oil production is not from the Peninsular Ranges province. The exceptions are Orange county’s southernmost oil fields in Huntington Beach and Newport Beach which extend south of the basin along the marine terraces, the beach, and the Newport-Inglewood fault zone (Box Figure \(\PageIndex{1}\)).

Box Figure \(\PageIndex{1}\): Huntington Beach in 1926 – a sea of oil derricks with the old Huntington Inn and the Red Car, the electric train from Los Angeles. "Huntington Beach, 1926" is copied courtesy of the Orange County Archives and is licensed under CC BY 2.0.

The Huntington Beach oil field was discovered in 1920 and is still in production today. Peak production was achieved in 1923 with 156 producing wells. It is a “supergiant” oil field having produced over a billion barrels of oil from 1920 to 2000 and is the fifth largest oil field in California. One of the interesting historical facts about this oil field is that it is one of the earliest oil fields discovered on the recommendation of geologists. Most oil wells drilled at the time were by “wildcatters” men with much drilling experience and little formal geology training. The first well was drilled by Standard Oil of California (today's Chevron Corporation) and they were planning on drilling in Newport Beach, but a company geologist sent to evaluate the recommended prospect in Newport Beach strongly suggested that instead the company drill the first well in Huntington Beach.

Drilling began in a barley field in December of 1919 and oil was discovered at a depth of 725 m (2379 feet). It went into production at a rate of 70 barrels of oil a day in May of 1920 and altered the history of the city of Huntington Beach by increasing the interest in drilling in the area. The second well drilled, Bolsa Chica #1, would change the history of Huntington Beach. It was completed at 777 m (2549 feet) as an uncontrolled gusher. It blew out and started an environmental disaster with 1742 gallons a day flowing into the lowlands, but the oil boom was on. Gold rush, oil boom; the pattern was the same, people flocked to the area in search of potential opportunities and riches.

Lease prices on the land within and around Huntington Beach skyrocketed from $25-$50 an acre to over $1000 an acre. By the end of 1920 all the land for 4 miles around the discovery well, Huntington A-1, was leased. Population exploded as oil well after oil well was drilled and began producing. It took a crew of 15 men to maintain an individual oil well on a weekly basis, and within months the population of Huntington Beach had jumped from about 1500 to over 6000. Everything was in demand, housing, food, clothing, recreation. Among other businesses, five pool halls were built, and they became unofficial hiring halls for oil field workers. Scams, graft, and illicit business flourished. And many made fortunes and employment was high.

One scheme that was not a scam is worth noting. In 1916, before the oil field was discovered, an encyclopedia company had been offering a deal – buy a set of encyclopedia and get a small lot for free. Land was cheap enough then that the encyclopedia company could afford to buy a set of lots, subdivide them, and give them away as a promotion for buying encyclopedias. The lots were very well placed and the people who had bought encyclopedias made small fortunes from oil leases.

For decades Huntington Beach had a boom and a not-quite-as-bad-as-bust economy, with good years and bad, depending upon the variations in the price of oil, regulation, and the national economy. In the 1950s the city started on a program to have the oil companies clean-up and remove the old wooden derricks and replace them with steel pumping units. By 1964, Huntington Beach had 1776 active oil wells producing just over 16 million barrels of oil. By the 1970s land was becoming more valuable for housing and oil production declined as wells were capped.

In 1991, Huntington A-1 was permanently sealed by filing it with cement, a process known as "abandonment", which ensures the well is safely closed off. It had been inactive and non-operational since 1968. By 2000, over a billion barrels of oil had been produced along with 845cf of natural gas. The Huntington Beach oil field however is still producing and in 2013 the US Geological Survey estimated that there are still probably 3500 million barrels of oil left to produce.

Building Commodities

As with most of the world, the most common commodities mined in the Peninsular Ranges province are those needed to maintain the infrastructure and to build towns and cities – gravel and sand and fill dirt (concrete, roadbeds, fill), limestone and marble (concrete, cement, and steel production), building stone and dimension stone (riprap, buildings and ornamental stone features), clay (sewer pipe, tile, and pottery), gypsum (plaster and drywall), silica and specialty sand (glassmaking, ceramics, abrasives, electronics, computer chips, steel production), and gemstones (adornment, lasers, abrasives, and cutting tools).

Sand and gravel are the most commonly mined building materials. Commonly called aggregate, these materials are used in making concrete, back top, plaster and stucco for buildings. Also, it is used as road base, railroad ballast, and fill. The economic complication that arises with aggregate is that it is bulky, heavy, and has a comparatively low-unit cost as a commodity. Therefore, it needs to be mined close to where it will be used, or the transportation costs can dramatically increase the fuel consumption driving up building costs; and the fuel consumption and gas emissions can dramatically increase air pollution.

What this means geologically is that in most urban areas, there is always a need for a nearby source of aggregate. The Peninsular Ranges are no exception and almost any stream coming out of the mountains or their foothills, dumps sand and gravel when the slope gets gentler at their base and the streamflow slows (Figure \(\PageIndex{3}\)). Therefore, there is an extensive history of ongoing, open pit aggregate mining at the base of the Peninsular Ranges and their foothills. The mountain front is where gravel pits are mined and abandoned, and reopened, as needed depending upon local building projects. Predictions by the California Geological Survey in 2018 are that there is approximately 41 to 50 years worth of reserves in Orange and Riverside counties and 11 to 20 years of reserves for San Diego county.

Figure \(\PageIndex{3}\): Abandoned, and now flooded, gravel pit in Santiago Creek, Orange, California. "Flooded Gravel Pit in Santiago Creek" by Debra Brooks is licensed under CC BY-NC 4.0.

Limestone and marble for cement making is still actively quarried in the northern Peninsular Ranges mostly in the area around Riverside, California, and areas in the northern Perris Block. While marble and limestone have been mined in both San Diego and Orange counties in the past, their deposits are relatively small and today mining is concentrated in Riverside county. Quarrying limestone and marble for cement started in the 1890s. During WWII it was extensively quarried for use in the former steel mills of Fontana, California. While the steel mills may be closed, building still continues in southern California, and therefore, so does quarrying marble to make cement.

Quarrying dimension stone and building stone also has a history throughout the Peninsular Ranges. Nationally most of the dimension stone used is marble, and while some marble is mined for building use in the Peninsular Ranges, most of the dimension stone mined is plutonic igneous rock, mostly granite and other felsic igneous rock, but also some gabbro.

Most of the granite in the Transverse Ranges is highly fractured and cannot be used for dimension stone, therefore the Peninsular Ranges have become the major source for most of the dimension stone used in southern California. Granite and other plutonic igneous rock have been used for riprap in breakwaters and jetties, as well as for building facings, flooring, monuments, and even kitchen countertops. Most of today’s quarries are in Riverside or in San Diego counties. Of special importance for monuments and building facing is the “black granite” or gabbro, quarried in San Diego county. It has been highly prized since the 1920s and is not only used locally in California, but also in the rest of the nation and internationally.

Clay has been mined throughout the Peninsular Ranges province since the 1880s, but most of the clay mined today is in either Riverside or Orange Counties. Of special interest is kaolin, or kaolinite, the clay used to make porcelain and fine china which is found in the Silverado Formation and mined in the Alberhill district in the Temescal Valley of the Perris Block in Riverside county. The other common use for kaolinite is in cement production and this is how most of the kaolinite mined in Riverside county is used. Common clay, which is the most commonly mined clay, is mostly used for sewer pipe, tile, bricks, pottery, and as a liner for solid waste dumps. It is found in the Ladd Formation and also mined in the Alberhill district of Riverside county as well as many other locales, including El Toro and San Juan Capistrano in Orange county.

Gypsum and silica, two other building commodities, were historically mined in the Peninsular Ranges province. Gypsum, along with sand, gravel, and clay was once mined in Gypsum Canyon in Orange county, but those mines are long closed. The sand and gravel pits were the last to close and they closed in 2004. Plans are to use the site for a veteran’s cemetery and as open space. Silica was also mined in both Riverside and Orange counties. The primary use was for glass making and again the silica sand mines are closed. In Orange county the silica mine was an open pit mine in Mission Viejo that closed in the 1990s and is now an industrial-business complex. In Riverside county the silica was once mined in Temescal Canyon, Corona, and near Hemet.

Other Commodities – Still Mined or Once Mined

The other commodity still mined in the Peninsular Ranges province are gemstones (see Rocks of the Peninsular Ranges). Pala and the other pegmatite districts in northern San Diego county and southern Riverside county still have open mines, but they are mostly aimed at providing minerals for collectors and museums, and not engaged in any large-scale mining operations.

There are two other commodities that have been mined in the past – coal and salt. Low quality, lignite coal has been mined in Riverside county at Alberhill and in Orange county in Black Star Canyon in the late 1800s. These mines were relatively small operations and are long closed. Although the coal mine in Black Star Canyon was temporarily reopened during WWII. Salt was also mined by the Irvine Company for use in water softening systems in upper Newport Back Bay of Orange County from the 1930s until 1969. The Salt Works were closed because of extensive damage from the flood of 1969 (Figure \(\PageIndex{4}\)).

Figure \(\PageIndex{4}\): The Salt Works in Newport Back Bay, Orange County California. "Salt Works, Upper Newport Bay" is courtesy of the Orange County Archives and is licensed under CC BY 2.0.

The history of resources in the Peninsular Ranges province, as in most of California, is one of change. In the popular accounts of American history, California began with a gold rush. Comparatively few people, however, profited from the 1849 Gold Rush. Far more extensive, and ultimately more useful, has been the mining of mineral commodities necessary to build the cities, towns, railroads, roads, freeways, and airports of today. Without these resources, it would be very difficult to accommodate the large population that now lives in southern California.

Query \(\PageIndex{1}\)

References

1. Almanza, R. (2024, June 24). Anaheim Approves Orange County’s First Veterans Cemetery in Gypsum Canyon. The Department of California of the American Legion. https://calegion.org/anaheim-approves-orange-countys-first-veterans-cemetery-in-gypsum-canyon/
2. Brigandi, P. (2019). The Silverado Mining Boom of 1878. OC Historyland. https://www.ochistoryland.com/silverado
3. Clinkenbeard, J. P., & Gius, F. W. (2018). CGS Map Sheet 52: Aggregate Sustainability in California. California Geological Survey.
4. Currier, L. W. (1960). USGS Bulletin 1109: Geologic Appraisal of Dimension-Stone Deposits. U.S. Geological Survey.
5. Daviess, S. N., & Bramlette, M. N. (1953). USGS Open-File Report: The Alberhill and other clay deposits of Temescal Canyon, Riverside County, California. U.S. Geological Survey. https://doi.org/10.3133/ofr5352
6. Ferrell, D. (2002, May 9). Mountain Shifts Slowly From Stone to Cement. LA Times. https://www.latimes.com/archives/la-xpm-2002-may-09-surround-09-story.html
7. Gale, H. S. (1934). Geology of Huntington Beach Oil Field, California. Bulletin of the American Association of Petroleum Geologists 18(3) 327-343.
8. Jacobi, L., & Martin, S. (2009, March), Water Usage in Orange County: 2007-2008. Orange County Profiles. 14 (1) 1-4. CSUF Center for Demographic Research. https://www.fullerton.edu/cdr/_resources/pdf/profiles/profilesv14n1.pdf
9. Marquis, G. D. (2023). California Non-Fuel Mineral production 2020. California Geological Survey.
10. Metropolitan Water District of Southern California. (2024, April). Safeguarding Southern California’s Water Reliability. Fact Sheet: Diamond Valley Lake_ A Reservoir of Resilience. Metropolitan Water District of Southern California. https://www.mwdh2o.com/media/2iloidmg/2024_dvl-fact-sheet_final-for-web.pdf
11. Metropolitan Water District of Southern California. (n.d.). How We Get Out Water: Infrastructure Serving Our Communities. Metropolitan Water District of Southern California. https://www.mwdh2o.com/your-water/how-we-get-our-water/
12. Miller, R. V., Shumway, D. O., & Hill, R. L. (1991). CDMG Special Report 165: Mineral land Classification of the Temescal Valley Area, Riverside County, California. California Division of Mines and Geology. https://www.conservation.ca.gov/cgs/Documents/Publications/Special-Reports/SR_165-MLC-Report.pdf
13. Mindat.org (n.d.). Blue Light Mine, Silvarado, Orange County, California, USA. [Data set]. https://www.mindat.org/loc-28559.html
14. Mindat.org (n.d.). Julian Mining District, San Diego County, California, USA. [Data set]. https://www.mindat.org/loc-3558.html
15. Mindat.org (n.d.). Pinacate Mining District, Riverside County, California, USA. [Data set]. https://www.mindat.org/loc-295044.html
16. Mindat.org (n.d.). Temescal Valley, Riverside County, California, USA. [Data set]. https://www.mindat.org/loc-293875.html
17. Mount, J., Hanak, E. & Peterson, C. (2023, April). Fact Sheet: Water Use in California. Public Policy Institute of California. https://www.ppic.org/publication/water-use-in-california/
18. Municipal Water District of Orange County. (2023, July). Water Reliability Study. Municipal Water District of Orange County. https://www.mwdoc.com/wp-content/uploads/2023/08/MWDOC_2023-OC-Water-Reliability-Study-Final.pdf
19. Naishadham, S. (2022, May 29) How San Diego secured its water supply, at a cost. Associated Press. https://apnews.com/article/california-droughts-environment-san-diego-81ab84fafe94a0c5c298ede24fd2f7f1#
20. Odell, A., Bower, S., Funk, A., & Cleveland, L. (2021, December). Final Report: San Diego Basin Study. Bureau of Reclamation and the City of San Diego Public Utilities Department. https://www.sandiego.gov/sites/default/files/2023-11/Copy%20of%20SDBS%20Final%20Report%20Dec%202021%20%28April%202022%29.pdf
21. Perazzo, P. B., & Perazzo, G. P. (2024). San Diego County Stone Industry. Stone Quarries and Beyond. https://quarriesandbeyond.org/states/ca/quarry_photo/ca-san_diego_indus_2.html
22. Robbins, J. (2019, June 11) As Water Scarcity Increases, Desalination Plants Are on the Rise. Yale Environment 360. Yale School of the Environment https://e360.yale.edu/features/as-water-scarcity-increases-desalination-plants-are-on-the-rise
23. Silva, A. (2000, March 19). Diamond Valley Lake Reservoir Dedicated Project Doubles Region’s Storage Capacity. Los Angeles Daily News https://web.archive.org/web/20140113195844/http://www.thefreelibrary.com/DIAMOND+VALLEY+LAKE+RESERVOIR+DEDICATED+PROJECT+DOUBLES+REGION%27S...-a083421758
24. Todd, V. R. (2015). USGS Open-File Report 94-16: Geologic map of the Julian 7.5” quadrangle, San Diego County, California. U.S. Geological Survey. https://doi.org/10.3133/ofr9416
25. Water Systems Consulting, Inc. (2021, July 1). City of Riverside 2020 Urban Water Management Plan. City of Riverside Public Utilities. https://riversideca.gov/utilities/sites/riversideca.gov.utilities/files/pdf/residents/RPU%20Final%202020%20UWMP%20%282%29.pdf
26. Weber, F. H. Jr., (1963). CDMG County Report 3: Geology and Mineral Resources of San Diego County, California. California Division of Mines and Geology.
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References for Box \(\PageIndex{1}\): Oil and Gas in the Peninsular Ranges Province

1. Gautier, D. L., Tennyson, M. E., Cook, T. A., Charpentier, R. R., & Klett, T. R. (2013, February). Remaining Recoverable Petroleum in Ten Giant Oil Fields of the Los Angeles Basin, Southern California. U.S. Geological Survey Fact Sheet 2012-3120. https://pubs.usgs.gov/fs/2012/3120/fs2012-3120.pdf
2. Higgins, D. G. (City Historian). (1976). Oil Fields – A Brief History of the Oil Fields at Huntington Beach, California. City of Huntington Beach Public Library. https://cms3.revize.com/revize/huntingtonbeachca/Documents/Departments/Library/Contact%20Us%20About/Historical%20Files/Historical%20Files%20Oil/070920-6.pdf
3. Pepper, A. (1991, January 24). City’s first oil well to be preserved. Orange County Register. https://cms3.revize.com/revize/huntingtonbeachca/Documents/Departments/Library/Contact%20Us%20About/Historical%20Files/Historical%20Files%20Oil/090518-22.pdf
4. Testa, S. M. (2007). History of Oil Along the Newport-Inglewood Structural Zone – Los Angeles County, California. Oil-Industry History 8(1) 9-35. Petroleum History Institute. https://aegsc.org/chapters/inlandempire/pdf/Oil-Industry%20History%20Volume%208%20Nov%201%202007.pdf
5. Yerkes, R. F., McCulloh, T. H., Schoellhamer, J. E., & Vedder, J. G. (1965). USGS Professional Paper 420-A: Geology of the Los Angeles Basin, California – an Introduction. U.S. Geological Survey.