Yorktown Formation and Duplin Formation, Undivided (NCTpy;11)

State	North Carolina
Name	Yorktown Formation and Duplin Formation, Undivided
Geologic age	Tertiary
Original map label	Tpy
Primary rock type	clay or mud
Secondary rock type	sand
Other rock types	limestone
Lithologic constituents	Major Unconsolidated > Fine-detrital > ClayYorktown Formation: fossiliferous clay Minor Sedimentary > Carbonate > LimestoneDuplin Formation: limestone, bluish gray Unconsolidated > MarlDuplin Formation: sandy marl Unconsolidated > Coarse-detrital > SandYorktown Formation: varying amounts of fine-grained sand, bluish gray, shell material commonly concentrated in lenses; Duplin Formation: shelly, medium- to coarse-grained sand, sandy marl
Map references	The North Carolina Dept. of Environment, Health, and Natural Resources, Division of Land Resources, NC Geological Survey, in cooperation with the NC Center for Geographic Information and Analysis, 1998, Geology - North Carolina (1:250,000), coverage data file geol250. The data represents the digital equivalent of the official State Geology map (1:500,000 scale), but was digitized from (1:250,000 scale) base maps.
Unit references	Rhodes, Thomas S., and Conrad, Stephen G., 1985, Geologic Map of North Carolina: Department of Natural Resources and Community Development, Division of Land Resources, and the NC Geological Survey, 1:500,000-scale, compiled by Brown, Philip M., et al, and Parker, John M. III, and in association with the State Geologic Map Advisory Committee. The North Carolina Dept. of Environment, Health, and Natural Resources, Division of Land Resources, NC Geological Survey, in cooperation with the NC Center for Geographic Information and Analysis, 1998, Geology - North Carolina (1:250,000), coverage data file geol250. The data represents the digital equivalent of the official State Geology map (1:500,000 scale), but was digitized from (1:250,000 scale) base maps.
Geographic coverage	Beaufort - Bertie - Bladen - Carteret - Chowan - Columbus - Craven - Duplin - Edgecombe - Gates - Greene - Halifax - Hertford - Hoke - Johnston - Jones - Martin - Nash - Northampton - Onslow - Pamlico - Pender - Perquimans - Pitt - Robeson - Sampson - Scotland - Washington - Wayne - Wilson