Mission Valley Formation

The Mission Valley Formation is a marine sandstone geologic formation in the Mission Valley region of southwestern San Diego County in Southern California.
Geology.
The formation's sandstone characteristics are: soft and friable, light olive gray, fine to medium grained, and composed mostly of quartz and potassium feldspar. The Mission Valley Formation thins from the west to the east, with a maximum thickness of .
It overlies the Stadium Conglomerate formation, and underlies the Pomerado Conglomerate formation.
Fossils.
It preserves fossils dating back to the Paleogene period of the Cenozoic Era. The formation's rocks can contain a molluscan fauna in the western and central exposures and a land-mammal fauna in the eastern exposures.