The Coastal Plain of North Carolina covers part or all of 41 counties in the state. The Piedmont Province adjoins the Coastal Plain on the west at the Fall Line, and the Blue Ridge Province lies west of the Piedmont.
The Coastal Plain sediments are, for the most part, consolidated sands, shales, and marls, which locally may be cemented into limestones. These sediments range in thickness from a feather edge at the Fall Line to 1,300 feet at the Pam-Bo Drilling Company's well in Hertford County, 10,000 feet at Hatteras Light No. 1 in Dare County, and 1,900 feet in a well at Fort Caswell, Brunswick County.
The sediments overlie the basement complex, which in most cases is a deeply weathered granite but one of the holes in Pamlico County probably ended in “Carolina slates.” In the western part of the Coastal Plain the surface of the basement rocks slopes about 14 feet per mile, whereas in the eastern part of the Plain the buried surface slopes about 122 feet per mile. This change in slope is evident on sections A, B, and C (Figs. 115 and 116). It is not known if this change in slope represents a monoclinal fold, a fault, or the change in grade between the Schooley Peneplain on the west and an unnamed peneplain on the east.
Various unpublished geophysical maps, especially those of magnetic surveys, show numerous anomalies. Sections A and B show very slight changes in the slope of the steeper part of