| Great Valley Sequence | |
|---|---|
| Stratigraphic range: Late Jurassic through Cretaceous | |
 Geologic map showing location of the Great Valley Sequence. Modified from Irwin (1990)[1] | |
| Type | Sedimentary |
| Underlies | Cenozoic sedimentary fill |
| Overlies | Basement |
| Thickness | up to 40,000 feet (12 km)[2] |
| Lithology | |
| Primary | shale and sandstone |
| Other | minor conglomerate |
| Location | |
| Region | Great Valley-Central Valley of California |
| Country | United States |
| Type section | |
| Named for | Great Valley-(Central Valley) of California |
| Named by | Baily, Irwin & Jones (1964)[2] |
The Great Valley Sequence of California is a 40,000-foot (12 km)-thick group of related geologic formations that are Late Jurassic through Cretaceous in age (150–65 Ma) on the geologic time scale. These sedimentary rocks were deposited during the late Mesozoic Era in an ancient seaway that corresponds roughly to the outline of the modern Great Valley (Central Valley) of California.