The California Geological Survey has compiled several updated and new geologic maps that are considered Preliminary, awaiting official publication. We make digital versions of these Preliminary maps available before publication so you may have timely access to the information.
Below: Index map showing availability of Preliminary and Published maps of the current Regional Geologic Map series. Click or tap the image to see a larger version.
You can download our Preliminary Regional Geologic Maps using the links provided below.
Please note, our Preliminary maps are available as PDF files only. Printed versions are not available.
Preliminary 30-by-60 Minute Quadrangles (1:100,000 scale)
Alturas, 2016
Cedarville, 2017
Crescent City-Orick, 2012
Eagle Lake, 2014
Lodi, 2009
Long Beach, 2016
Los Angeles, 2016
Napa-Bodega Bay, 2017
Pt. Sur, 2016
Sacramento, 2011
Santa Barbara (east half), 2008
Susanville, 2013
Preliminary 7.5 Minute Quadrangles (1:24,000 scale)
Click a region in the list below to jump to a list of that region's 7.5 minute quadrangles.
Northern San Francisco Bay Region
Note: The 7.5 minute quadrangles within the Napa 30-by-60 minute quadrangle (shown above in red) have been updated and are superseded by the Preliminary Geologic Map of the Napa-Bodega Bay 30-by-60 minute quadrangle (Wagner and Gutierrez, 2017).
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Calistoga, 2013 (4.1 MB)
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Camp Meeker, 2009 (7.2 MB)
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Capell Valley, 2006 (7.7 MB)
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Cordelia, 1998 (3.6 MB)
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Cotati, 2003 (4.2 MB)
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Cuttings Wharf, 2002 (3.0 MB)
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Fairfield North, 2006 (6.2 MB)
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Fairfield South, 1998 (2.7 MB)
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Geyserville, 2012 (3.6 MB)
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Glen Ellen, 2003 (5.4 MB)
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Healdsburg, 2011 (8.2 MB)
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Jimtown, 2010 (9.0 MB)
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Kenwood, 2007 (2.4 MB)
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Mt. George, 2004 (3.4 MB)
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Mt. Vaca, 2007 (2.8 MB)
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Napa, 2004 (3.8 MB)
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Novato, 2002 (2.3 MB)
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Petaluma, 2002 (2.5 MB)
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Petaluma River, 2002 (1.6 MB)
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Rutherford, 2005 (11 MB)
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Sears Point, 2002 (2.0 MB)
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Sebastopol, 2008 (3.7 MB)
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Sonoma, 2004 (3.7 MB)
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Two Rock, 2003 (4.0 MB)
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Valley Ford, 2008 (4.6 MB)
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Yountville, 2005 (10 MB)
Central Sierra Foothills Region
San Luis Obispo Region
Lancaster-Victorville Region
Santa Barbara-Los Angeles Region
Note: The 7.5 minute quadrangles within the Los Angeles 30-by-60 minute quadrangle (shown above in red) have been updated and are superseded by the Preliminary Geologic Map of the Los Angeles 30-by-60 minute quadrangle (Campbell, et al, 2014).
Oceanside-San Diego Region
Note: The 7.5 minute quadrangles within the Oceanside 30-by-60 minute quadrangle (shown above in red) have been updated and are superseded by the Geologic Map of the Oceanside 30-by-60 minute quadrangle (Kennedy and Tan, 2007).
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Aguanga, 2014 (5.2 MB)
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Bonsall, 2000 (3.2 MB)
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Boucher Hill, 2014 (8.9 MB)
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Dana Point, 1999 (2.3 MB)
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El Cajon, 2002 (2.2 MB)
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Escondido, 1999 (2.7 MB)
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Fallbrook, 2000 (4.7 MB)
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Jamul Mountains, 2002 (2.1 MB)
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Las Pulgas Canyon, 2001 (3.7 MB)
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Margarita Peak, 2001 (5 MB)
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Morro Hill, 2001 (3 MB)
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Otay Mesa, 2002 (1.2 MB)
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Pala, 2000 (4 MB)
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Pechanga, 2000 (4.2 MB)
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Ramona, 2007 (4.0 MB)
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San Clemente, 1999 (5.2 MB)
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San Onofre Bluff, 1999 (1.9 MB)
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San Pasqual, 2007 (2.5 MB)
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San Vicente Reservoir, 2002 (1.7 MB)
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Temecula, 2000 (4.8 MB)
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Vail Lake, 2014 (6.2 MB)
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Valley Center, 1999 (3.3 MB)
About CGS Preliminary Regional Geologic Maps
The California Geological Survey prepares geologic maps in cooperation with the U.S. Geological Survey’s National Cooperative Geologic Mapping Program. We prepare Preliminary maps as 7.5 minute quadrangles at 1:24,000 scale, which we then compile into 30-by-60 minute quadrangles at 1:100,000 scale. The 30-by-60 minute quadrangles include all of the detail of the 7.5 minute quadrangles. When an entire 30-by-60 minute quadrangle is compiled, reviewed, and approved, we release it into our official
Published Regional Geologic Map series.
Geologic mapping priorities are established by the California State Geologist and the California Geologic Mapping Advisory Committee.
Technical comments can be emailed to
Marc Delattre
