Geologic Formations of the San Joaquin Valley

ERA	Epoch		Strat Units
ERA	Epoch		Strat Units
	Holocene		ALLUVIUM
	Pleistocene		TULARE FM




	Pliocene		SAN JOAQUIN FM (under Construction)



			ETCHEGOIN FM (under Construction)


	Miocene	Upper		REEF RIDGE


				BELRIDGE DIATOMITE
				BELRIDGE DIATOMITE
				ANTELOPE




				MCDONALD






		Middle		DEVILWATER


				GOULD
				GOULD
				MEDIA
		Lower		MEDIA
				CARNEROS





				UPPER SANTOS







	Oligocene			AGUA
				LOWER SANTOS







				PHACOIDES



SALT CREEK
SALT CREEK

CYMRIC SHALE
CYMRIC SHALE
TUMEY
	Eocene	Upper


OCEANIC

		Middle

KREYENHAGEN






POINT of ROCKS





KREYENHAGEN



CANOAS





Lower			YOKUT
			GATCHELL
			ARROYO HONDO


			CANTUA






Paleocene	Upper






			DOMENGINE

		UNCONFORMITY (Missing Section)
		UNCONFORMITY (Missing Section)

			WHEATVILLE




	Lower



	Cretaceous




			BLEWETT







			RAGGED VALLEY
			TRACY
			BROWN MOUNTAIN

			SAWTOOTH
				LATHROP


				JOAQUIN RIDGE




				FORBES








				BASEMENT

Formation names that are highlighted in blue are linked to a more
detailed description of the formation. Unfortunately the stratigraphy
of the San Joaquin Valley is rather complicated, and it can be quite
confusing. The stratigraphy shown here is greatly simplified.

Lithostratigraphic Column

Below is Geologic Time Chart, but due to space considerations it is not
drawn to scale. However, the link below does lead to a more detailed
Time Chart that is specific to California.

California Geologic Time Scale

Geologic Time Chart