| San Francisquito Formation | |
| Type: | Geologic formation |
| Age: | Maastrichtian-Danian ~ |
| Period: | Danian |
| Prilithology: | Sandy shale |
| Region: | Los Angeles County, California |
| Coordinates: | 34.6°N -118.6°W |
| Paleocoordinates: | 39.5°N -96.5°W |
| Underlies: | Castaic & Punchbowl Formations |
| Overlies: | San Gabriel Basement Complex |
| Thickness: | 4km (02miles) |
| Extent: | San Gabriel Mountains & Sierra Pelona Mountains |
The San Francisquito Formation is a geologic formation located in northern Los Angeles County, California.[1] [2]
Areas where it is exposed include: San Francisquito Canyon of the Sierra Pelona Mountains, as well as on the northwestern side of the Devil's Punchbowl gorge in the San Gabriel Mountains.[1] [2]
The San Francisquito Formation consists of marine deposits that originated during the Late Cretaceous period of the Mesozoic Era, and the Early Paleocene epoch in the Paleogene period of the Cenozoic Era.[1] [2] It is overlain by the Punchbowl Formation (east) and Castaic Formation (west), both of the Miocene and Pliocene epochs.[1] It overlies the crystalline San Gabriel Basement Complex.[1]
It is found between the San Andreas Fault on its north, and the Devil's Punchbowl Fault on its south.[1] [2] The Pliocene epoch Crowder Formation is to the northeast.[1]
It preserves fossils dating back to the Paleogene period.[3]