Mulholland Formation | |
---|---|
Stratigraphic range: Pliocene epoch Neogene Period | |
Type | Geologic formation |
Underlies | Leona Rhyolite |
Overlies | Bald Peak Basalt |
Lithology | |
Primary | siltstone, sandstone, conglomerates |
Location | |
Region | Berkeley Hills and San Leandro Hills, Alameda County and Contra Costa County, California |
Country | United States |
Type section | |
Named for | William Mulholland |
The Mulholland Formation is a Pliocene epoch geologic formation in the Berkeley Hills and San Leandro Hills of the East Bay region of the San Francisco Bay Area, California.[1] It is found within Alameda County and Contra Costa County.[1]
It overlies the Bald Peak Basalt formation, and underlies the Pleistocene epoch Leona Rhyolite formation.[1] It is composed of siltstone, sandstone, and conglomerates. It has fluviatile and lacustrine deposits.[1]
Descending under the Bald Peak Basalt formation are the Pliocene epoch units of the Siesta Formation, Moraga Formation, and Orinda Formation.[1] Below the Orinda are the local Miocene epoch units of the Monterey Formation Group: Tice Shale, Oursan Sandstone, Claremont Shale, and Sobrante Sandstone.[1]
The Mulholland Formation preserves fossils dating back to the Neogene period.[2]