| Purisima Formation | |
| Type: | Formation |
| Age: | Late Miocene-Early Pleistocene ~ |
| Period: | Neogene |
| Prilithology: | Sandstone, siltstone |
| Otherlithology: | Conglomerate, phosphorite |
| Region: | California |
| Country: | United States |
The Purisima Formation is a geologic formation in California that preserves fossils dating from the Late Miocene to Late Pliocene.[1] It stretches from Point Reyes to the Santa Cruz Mountains.