French
DeutschMulholland Formation
| 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]
Geology
[edit]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]
Fossils
[edit]The Mulholland Formation preserves fossils dating back to the Neogene period.[2]
Other local formations
[edit]- Units of other local formations in the Berkeley and San Leandro Hills, in descending geologic column order from higher/younger to lower/older, include:[1]
- Local Late/Upper Cretaceous−Pliocene units of the Chico Formation:
- Redwood Canyon Formation — sandstone, shale, and conglomerate.
- Shephard Creek Formation — shale and sandstone.
- Oakland Conglomerate — conglomerate, exposed on Skyline Boulevard.
- Joaquin Miller Formation — sandstone, shale, and conglomerate.
- Knoxville Conglomerate
See also
[edit]
- Pliocene geology in California
- List of fossiliferous stratigraphic units in California
- Paleontology in California
References
[edit]- ^ a b c d e f g USGS.gov: "Upper Cretaceous and Lower Tertiary Rocks Berkeley and San Leandro Hills, California", by J. E. Case, GEOLOGICAL SURVEY BULLETIN 1251-J, 1968.
- ^ Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
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