Moraga Formation

The Moraga Formation, also known as the Moraga Volcanics, is a geological formation that dates back to the Pliocene epoch. It is located in Berkeley Hills, East Bay Region, San Francisco Bay Area, California.^[1]

Moraga Formation (Moraga Volcanics)
Stratigraphic range: Pliocene epoch
Moraga Volcanics in Robert Sibley Volcanic Regional Preserve, Berkeley Hills
Type	Geologic formation
Underlies	Siesta Formation
Overlies	Orinda Formation
Thickness	1,200 feet (370 m)
Lithology
Primary	Basaltic lava, with andesite, basalt, rhyolite tuff
Other	Clay, conglomerate, limestone
Location
Region	Berkeley Hills, Alameda County and Contra Costa County, California
Country	United States
Type section
Named for	Moraga Valley

The basaltic lava flow formation is found within Alameda County and Contra Costa County.^[1][2] It can be seen in the Robert Sibley Volcanic Regional Preserve and Caldecott Tunnel area of the Berkeley Hills.^[3] It is named for an exposed occurrence in the Moraga Valley.

It overlies the Orinda Formation, and underlies the Siesta Formation.^[4]

It preserves freshwater fossils dating back to the Pliocene epoch of the Neogene period.^[5]

See also

• California portal
• Paleontology portal

• Mulholland Formation — occurs to the south, in the Berkeley and San Leandro Hills.
• Pliocene California geology
• List of fossiliferous stratigraphic units in California
• Paleontology in California