Peedee Formation /Black Creek Group, undivided (SCKpb;1)

State	South Carolina
Name	Peedee Formation /Black Creek Group, undivided
Geologic age	Cretaceous
Original map label	Kpb
Comments	Secondary unit description from USGS Lexicon (ref.SC003): Peedee Formation: Consists of dark-green or gray, finely micaceous, more or less glauconitic and argillitic sand, many layers of which are calcareous (impure limestone). Irregular concretionary masses of impure calcium carbonate occur in places. Dark marine clays are interstratified with sand. Black Creek Group: Consists of irregularly bedded, laminated, carbonaceous clays and thin laminae and lenses of sand; lignite and pyrite present; glauconitic in places; massive interbedded layers of glauconitic sand present toward top of unit. Light-colored clays and coarse arkosic sands found in SC (Chesterfield Co. and southward) formerly called Middendorf beds by Sloan (1908) revised as Middendorf arkose member of Black Creek formation (SC only) on the basis of fossil plants.
Primary rock type	clay or mud
Secondary rock type	sand
Other rock types	limestone
Lithologic constituents	Major Unconsolidated > Coarse-detrital > SandPeedee Formation: Consists of dark-green or gray, finely micaceous, more or less glauconitic and argillitic sand, many layers of which are calcareous (impure limestone). Irregular concretionary masses of impure calcium carbonate occur in places. Dark marine clays are interstratified with sand. Black Creek Group: Consists of irregularly bedded, laminated, carbonaceous clays and thin laminae and lenses of sand; lignite and pyrite present; glauconitic in places; massive interbedded layers of glauconitic sand present toward top of unit. Light-colored clays and coarse arkosic sands also found Unconsolidated > Fine-detrital > ClayPeedee Formation: Consists of dark-green or gray, finely micaceous, more or less glauconitic and argillitic sand, many layers of which are calcareous (impure limestone). Irregular concretionary masses of impure calcium carbonate occur in places. Dark marine clays are interstratified with sand. Black Creek Group: Consists of irregularly bedded, laminated, carbonaceous clays and thin laminae and lenses of sand; lignite and pyrite present; glauconitic in places; massive interbedded layers of glauconitic sand present toward top of unit. Light-colored clays and coarse arkosic sands also found Minor Sedimentary > Carbonate > LimestonePeedee Formation: Consists of dark-green or gray, finely micaceous, more or less glauconitic and argillitic sand, many layers of which are calcareous (impure limestone). Irregular concretionary masses of impure calcium carbonate occur in places. Dark marine clays are interstratified with sand. Black Creek Group: Consists of irregularly bedded, laminated, carbonaceous clays and thin laminae and lenses of sand; lignite and pyrite present; glauconitic in places; massive interbedded layers of glauconitic sand present toward top of unit. Light-colored clays and coarse arkosic sands also found
Map references	Newell, Wayne L., Prowell, David (retired), Krantz, David, Powars, David, Mixon, Robert (retired), Stone, Byron, and Willard, Debra, in review, Surficial Geology and Geomorphology of the Atlantic Coastal Plain: U.S.G.S. Open File Report,
Unit references	Newell, Wayne L., Prowell, David (retired), Krantz, David, Powars, David, Mixon, Robert (retired), Stone, Byron, and Willard, Debra, in review, Surficial Geology and Geomorphology of the Atlantic Coastal Plain: U.S.G.S. Open File Report, USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Chesterfield - Darlington - Kershaw - Lancaster - Lee - Marlboro - Richland - Sumter