Skip to main content

Midway Group; Clayton Formation

Clayton Formation - (Midway Group), White to yellowsih-gray argillaceous limestone occurs in the upper part (McBryde Limestone Member): the lower part is medium-gray fossiliferous calcareous silt, glauconitic sand and thin beds of sandy limestone and calcareous sandstone (Pine Barren Member). At the base of the formation in southeast AL is a gravelly medium to coarse sand containing clay pebbles. The formation thins west of Wilcox County and westward from Thomaston in eastern Marengo County is mapped with the Porters Creek Formation. The formation is generally deeply weathered and fresh exposures are rare. In western areas exposures consist of weathered white to yellowish-gray argillaceous, fossiliferous sandy limestone, ferruginous sand, and fossiliferous sandstone. In eastern areas exposures consist of residual accumulations of chert boulders, moderate-reddish-orange sand, and clay containing masses and thin layers of iron minerals (limonite-goethite).
State Alabama
Name Midway Group; Clayton Formation
Geologic age Paleocene
Primary rock type limestone
Secondary rock type clay or mud
Other rock types silt; sandstone; chert
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)White to yellowsih-gray argillaceous limestone, yellowish-gray argillaceous, fossiliferous sandy limestone.
Minor
Unconsolidated > Coarse-detrital > Sand (Bed)glauconitic sand, ferruginous sand
Unconsolidated > Fine-detrital > Silt (Bed)the lower part is medium-gray fossiliferous calcareous silt
Sedimentary > Clastic > Sandstone (Bed)calcareous sandstone (Pine Barren Member), fossiliferous sandstone.
Unconsolidated > Fine-detrital > Clay
Incidental
Sedimentary > Chemical > Chert
Map references
Szabo, M. W., Osborne, E. W., Copeland, C. W. Jr., Neathery; T. L., 1988, Geologic Map of Alabama, Geological Survey of Alabama Special Map 220, scale 1:250,000.
Unit references
Szabo, M. W., Osborne, E. W., Copeland, C. W. Jr., Neathery; T. L., 1988, Geologic Map of Alabama, Geological Survey of Alabama Special Map 220, scale 1:250,000.
Counties Barbour - Bullock - Butler - Crenshaw - Dallas - Henry - Lowndes - Marengo - Pike - Wilcox