Capistrano Formation
| Capistrano Formation | |
|---|---|
| Stratigraphic range: Miocene to Pliocene | |
| Type | Formation |
| Sub-units | Oso Member, unnamed siltstone member |
| Underlies | Niguel Formation |
| Overlies | Monterey Formation |
| Thickness | 850 m |
| Lithology | |
| Primary | Siltstone, Arkose |
| Other | Breccia, Mudstone |
| Location | |
| Region | Orange County, California |
| Country | United States |
| Type section | |
| Named for | San Juan Capistrano |
| Named by | Alfred Oswald Woodford |
| Year defined | 1925 |
Outcrops of the Oso Member, with the type locality of Titanotaria highlighted | |
The Capistrano Formation is a geologic formation in coastal southern Orange County, California. It preserves fossils dating back to the late Miocene to early Pliocene, with the Oso Member representing a near-shore environment. Fifty-nine species and varieties of foraminifera are recognized from the Capistrano Formation alongside a diverse array of marine mammals including up to five species of walrus.