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Preliminary Geologic Maps

The CGS preliminary geologic map series is intended to provide timely access to digital geologic maps being prepared by CGS in cooperation with the U.S. Geological Survey’s National Cooperative Geologic Mapping Program. These maps are in preliminary format and are available as PDF images only.


Maps are prepared based on original geologic mapping and compilation as 1:24,000 scale 7.5-minute quadrangles and 1:100,000 scale 30 x 60 minute quadrangles. Compilation of 30 x 60 minute quadrangles includes all of the detail of included 7.5 minute quadrangles and commonly updates mapping to produce a seamless geologic map of the region. When all aspects of the geologic mapping of a region are compiled and reviewed, the 30 x 60 minute quadrangles are published in CGS’s Regional Geologic Map series. The listing below shows preliminary 7.5 minute quadrangles and 30 x 60 minute quadrangles as well as the 30 x 60 minute quadrangles that have been published as Regional Geologic Maps.

Click on quadrangle name in the list below to view or download the quadrangle. To view, click on the name of the quadrangle to open in Adobe Acrobat. From Acrobat you can download the map by selecting "save as" under the file menu and save to desired location. To download without opening the map, right click on the quadrangle name, and select "save target as" to save the file to the location you wish.

Technical comments can be sent to Marc Delattre: Marc.Delattre@conservation.ca.gov

30x60-minute Quadrangles:

Preliminary Maps

Crescent City - Orick, 2012
Geologic Map (5.2 MB)
Pamphlet (1.2 MB)

Eagle Lake, 2014
Geologic Map (5 MB)
Pamphlet (1.5 MB)

Lodi, 2009
Geologic Map (28.9 MB)
Pamphlet (1 MB)

Los Angeles, 2014
Geologic Map (13.9 MB)
Pamphlet (2.7 MB)

Napa, 2010
Geologic Map (13.3 MB)
Pamphlet (1 MB)

Sacramento, 2011
Geologic Map (37.5 MB)
Pamphlet (1 MB)

Santa Barbara (East half), 2008
Geologic Map (32 MB)
Pamphlet (1 MB)

Susanville, 2013
Geologic Map (6.6 MB)
Pamphlet (5.3 MB)


Published Maps

The following geologic maps have been published as part of the Regional Geologic Map (RGM) series. These maps and other RGM maps can be purchased through the CGS Publications.

Preliminary 7.5-minute Quadrangles:


Northern San Francisco Bay Region:


Note: The 7.5-minute quadrangles within the Napa 30x60-minute quadrangle (shown above in red) have been updated and are superseded by the Preliminary Geologic Map of the Napa 30x60-minute Quadrangle (Wagner and Gutierrez, 2010).

Calistoga, 2013 (4.1 MB)
Camp Meeker, 2009 (7.2 MB)
Capell Valley, 2006 (7.7 MB)
Cotati, 2003 (4.2 MB)
Cuttings Wharf, 2002 (3.0 MB)
Fairfield North, 2006 (6.2 MB)
Geyserville, 2012 (3.6 MB)
Glen Ellen, 2003 (5.4 MB)
Healdsburg, 2011 (8.2 MB)
Jimtown, 2010 (9.0 MB)
Kenwood, 2007 (2.4 MB)
Mt. George, 2004 (3.4 MB)
Mt. Vaca, 2007 (2.8 MB)
Napa, 2004 (3.8 MB)
Novato, 2002 (2.3 MB)
Petaluma, 2002 (2.5 MB)
Petaluma River, 2002 (1.6 MB)
Rutherford, 2005 (11 MB)
Sears Point, 2002 (2.0 MB)
Sebastopol, 2008 (3.7 MB)
Sonoma, 2004 (3.7 MB)
Two Rock, 2003 (4.0 MB)
Valley Ford, 2008 (4.6 MB)
Yountville, 2005 (10 MB)


Central Sierra Foothills Region:



Ione, 2015 (2.8 MB)
Valley Springs, 2015 (3.3 MB)
Wallace, 2015 (3.3 MB)


San Luis Obispo Region:



Arroyo Grande, 2013 (3.7 MB)
Atascadero, 2012 (3.6 MB)
Morro Bay South, 2009 (6.1 MB)
Nipomo, 2014 (4 MB)
Oceano, 2013 (3.1 MB)
Pismo Beach, 2011 (4.5 MB)
San Luis Obispo, 2010 (5.5 MB)
Santa Margarita, 2015 (4 MB)

Lancaster-Victorville Region:



Apple Valley North, 2007 (3.1 MB)
Del Sur, 2010 (4.6 MB)
Fairmont Butte, 2011 (3.9 MB)
Grapevine, 2014 (3.5 MB)
Lake Hughes, 2011 (6 MB)
Lancaster East, 2011 (3.5 MB)
Lancaster West, 2010 (3.8 MB)
Little Buttes, 2012 (2.1 MB)
Palmdale, 2013 (4.2 MB)
Ritter Ridge, 2009 (8.6 MB)
Sleepy Valley, 2012 (4.3 MB)
Victorville, 2008 (6.4 MB)


Santa Barbara-Los Angeles Region:




Note: The 7.5-minute quadrangles within the Los Angeles 30x60-minute quadrangle (shown above in red) have been updated and are superseded by the Preliminary Geologic Map of the Los Angeles 30x60-minute Quadrangle (Campbell, et al, 2014).

Baldwin Park, 1997 (9.2 MB)
El Monte, 1997 (11.2 MB)
Matilija, 2006 (6.1 MB)
Ojai, 2005 (10 MB)
Oxnard, 2003 (2.2 MB)
Pitas Point, 2003 (2.1 MB)
Point Mugu, 2003 (5.2 MB)
Santa Paula, 2004 (3.6 MB)
Santa Paula Peak, 2005 (11 MB)
Saticoy, 2004 (4.6 MB)
Ventura, 2003 (6 MB)
White Ledge Peak, 2004 (3.1 MB)
Whittier, 1996 (4.6 MB)


Oceanside-San Diego Region:



Note: The 7.5-minute quadrangles within the Oceanside 30x60-minute quadrangle (shown above in red) have been updated and are superseded by the Geologic Map of the Oceanside 30x60-minute Quadrangle (Kennedy and Tan, 2007).

Aguanga, 2014 (5.2 MB)
Bonsall, 2000 (3.2 MB)
Boucher Hill, 2014 (8.9 MB)
Dana Point, 1999 (2.3 MB)
El Cajon, 2002 (2.2 MB)
Escondido, 1999 (2.7 MB)
Fallbrook, 2000 (4.7 MB)
Jamul Mountains, 2002 (2.1 MB)
Las Pulgas Canyon, 2001 (3.7 MB)
Margarita Peak, 2001 (5 MB)
Morro Hill, 2001 (3 MB)
Otay Mesa, 2002 (1.2 MB)
Pala, 2000 (4 MB)
Pechanga, 2000 (4.2 MB)
Ramona, 2007 (4.0 MB)
San Clemente, 1999 (5.2 MB)
San Onofre Bluff, 1999 (1.9 MB)
San Pasqual, 2007 (2.5 MB)
San Vicente Reservoir, 2002 (1.7 MB)
Temecula, 2000 (4.8 MB)
Vail Lake, 2014 (6.2 MB)
Valley Center, 1999 (3.3 MB)