Altitude of basement surface in the central coastal plain area of North Carolina

The altitude of the basement surface in the central Coastal Plain of North Carolina ranges from 140 ft above sea level in Wayne County near the Fall Line to 2,400 ft below sea level near the coast in Beaufort County. The slope increases to the east from about 20 ft/mi at the fall line to about 70 ft/mi at the eastern edge of the study area. The irregular nature of the basement surface is demonstrated by: (1) the variable altitudes of the basement surface in the western portion of the study area; (2) the protruding granite/gneiss rock body at a quarry near the Town of Fountain, Pitt County; and (3) the flattening of the basement surface slope observed near the Jones County and Craven County border. Basement rock types in this study area include granite, granite gneiss, metavolcanic, and metasedimentary rocks of Precambrian to Paleozoic age.