CGS Preliminary Geologic Maps

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.

Map of California showing available quadrangles as summarized in the figure caption.

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

Geologic Map (13.8 MB)
Pamphlet (3.7 MB)

Cedarville, 2017

Geologic Map (12.7 MB)
Pamphlet (7.4 MB)

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)

Long Beach, 2016

Geologic Map (13.8 MB)
Pamphlet (485 kB)

Los Angeles, 2016

Geologic Map (31.2 MB)
Pamphlet (3.3 MB)

Napa-Bodega Bay, 2017

Geologic Map (26.7 MB)
Pamphlet (6.79 MB)
Correlation of Map Units (54 kb)

Pt. Sur, 2016

Geologic Map (24.3 MB)
Pamphlet (1.9 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)

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
Central Sierra Foothill Region
San Luis Obispo Region
Lancaster-Victorville Region
Santa Barbara-Los Angeles Region
Oceanside-San Diego Region

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The 7.5 minute quadrangles within the Napa 30-by-60 minute quadrangle (shown above in red) have been updated and are superseded by the Preliminary Geologic Map of the Napa-Bodega Bay 30-by-60 minute quadrangle (Wagner and Gutierrez, 2017).

Calistoga, 2013 (4.1 MB)
Camp Meeker, 2009 (7.2 MB)
Capell Valley, 2006 (7.7 MB)
Cordelia, 1998 (3.6 MB)
Cotati, 2003 (4.2 MB)
Cuttings Wharf, 2002 (3.0 MB)
Fairfield North, 2006 (6.2 MB)
Fairfield South, 1998 (2.7 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

Angels Camp, 2018 (23.0 MB)
Ione, 2015 (2.8 MB)
Irish Hill, 2016 (22.5 MB)
Jackson, 2019 (32 MB)
Jenny Lind, 2019 (16 MB)

San Andreas, 2017 (24.7 MB)
Valley Springs, 2015 (3.3 MB)
Valley Springs SW, 2018 (17.1 MB)
Wallace, 2015 (3.3 MB)

San Luis Obispo Region

Arroyo Grande, 2013 (3.7 MB)
Atascadero, 2012 (3.6 MB)
Cayucos, 2016 (16.3 MB)
Morro Bay North, 2016 (29.8 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)
Frazier Mountain, 2016 (29.7 MB)
Grapevine, 2014 (3.5 MB)
La Liebre Ranch, 2019 (22 MB)
Lake Hughes, 2011 (6 MB)
Lancaster East, 2011 (3.5 MB)

Lancaster West, 2010 (3.8 MB)
Lebec, 2017 (27.6 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 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).

Baldwin Park, 1997 (9.2 MB)
Camarillo, 2004 (2.3 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 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).

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)

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