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Mineral Resources > Online Spatial Data > Geology > by state > North Carolina Geology

Geologic units in Robeson county, North Carolina

Yorktown Formation and Duplin Formation, Undivided (Tertiary) at surface, covers 28 % of this area

Yorktown Formation and Duplin Formation, Undivided - Yorktown Formation: fossiliferous clay with varying amounts of fine-grained sand, bluish gray, shell material commonly concentrated in lenses; mainly in area north of Neuse River. Duplin Formation: shelly, medium- to coarse-grained sand, sandy marl, and limestone, bluish gray; mainly in area south of Neuse River.

Lithology: clay or mud; sand; limestone

Black Creek Formation (Cretaceous) at surface, covers 69 % of this area

Black Creek Formation - clay, gray to black, lignitic; contains thin beds and laminae of fine-grained micaceous sand and thick lenses of cross-bedded sand. Glauconitic, fossiliferous clayey sand lenses in upper part.

Lithology: clay or mud; sand

Middendorf Formation (Cretaceous) at surface, covers 3 % of this area

Middendorf Formation - sand, sandstone, and mudstone, gray to pale gray with an orange cast, mottled; clay balls and iron-cemented concretions common, beds laterally discontinuous, cross-bedding common.

Lithology: sand; sandstone; mudstone; clay or mud

Cape Fear Formation (Cretaceous) at surface, covers < 0.1 % of this area

Cape Fear Formation - sandstone and sandy mudstone, yellowish gray to bluish gray, mottled red to yellowish orange, indurated, graded and laterally continuos bedding, blocky clay, faint cross-bedding, feldspar and mica common.

Lithology: sandstone; mudstone; sand; clay or mud