Tejon Formation
Geologic formation in California, United States
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The Tejon Formation is a Paleogene period geologic formation in California.
Chico Formation (regionally)
| Tejon Formation | |
|---|---|
| Stratigraphic range: Paleogene | |
| Type | Formation |
| Underlies | Ione Formation (regionally) |
| Overlies | Martinez Formation (regionally), Chico Formation (regionally) |
| Thickness | 2,100–2,300 feet (640–700 m) |
| Lithology | |
| Primary | conglomerate, shale |
| Location | |
| Region | California |
| Country | United States |
| Type section | |
| Named for | Fort Tejon |
Geology
The formation regionally overlies the Martinez Formation or the Chico Formation.[1] Paleontology in the Tejon Formation indicates a more tropical climate than during the Martinez Formation's period, with fauna that flourished in its littoral conditions.[1]
Occurrences
It is predominantly found in the Fort Tejon area of the San Emigdio Mountains and Tehachapi Mountains in Kern County, and around Martinez in Contra Costa County.[1]
Areas it surfaces, south to north, include:[1]
- Santa Ana Mountains
- Santa Monica Mountains — near Calabasas.
- Simi Hills — eastern section
- Santa Susana Mountains — section in northwestern Simi Valley
- Santa Clara River Valley — Rancho Camulos area
- Topatopa Mountains — Sespe gorge area
- Fort Tejon area of the San Emigdio Mountains and Tehachapi Mountains
- San Joaquin Valley−Diablo Range — New Idria Mercury Mine area
- Mount Diablo — northern area
- Martinez area on the Sacramento Delta
- Clear Lake — Lower Lake area
Fossils
It preserves prehistoric plant and fauna fossils dating back to the Paleogene period of the Cenozoic Era.[2]
Species
Species (1897 taxa names) found only in the Tejon Formation include:[1]
- Cardita horni
- Fusus sequileteralis
- Megistostigma striata
- Modiola ornata
- Morio tuberculatus
- Telina martinezensis
- Telina horni
- Thracia karquinezensis
- Turritella conica
- Turritella infragranulata
- Tritonium eocenicum
