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St. Marks Formation
Stratigraphic range: Miocene
TypeRock sample from the St. Marks Formation
Unit ofNone
Sub-unitsNone
Lithology
Primary Limestone & sand
Location
Region Florida Panhandle
Country  United States
Extent Jefferson, Leon, and Wakulla counties
Type section
Named for St. Marks River
Named byJ. Finch, 1823
St. Marks Formation location in red.

The St. Marks Formation is a Miocene geologic formation in the eastern Florida Panhandle.

Age

Period: Neogene
Epoch: Miocene ~23.03 to 5.33 mya, calculates to a period of 17.7 million years
Faunal stage: Arikareean through Hemphillian

Location

The St. Marks Formation is exposed in Wakulla, southern Leon and southern Jefferson County, Florida on the northwestern flank of the Ocala Platform and along with Suwannee Limestone and Ocala Limestone makes up the upper part of the Floridan Aquifer in the eastern panhandle. [1]

Composition

The St. Marks Formation consists of a white to yellowish gray, poorly to moderately hard, sandy, fossil bearing rock in molds and casts within packstone to wackestone.

Fossils

The fossils are in molds and casts and include:

References