Where did the sediments of the Atlantic coastal plain come from?

The sediments of the Atlantic Coastal Plain primarily originated from the erosion of the Appalachian Mountains and surrounding highlands. Over millions of years, rivers and streams transported these eroded materials, including sand, silt, and clay, to the coastal areas. Additionally, sediment was deposited by glacial activity and sea-level changes, contributing to the formation of the coastal plain. This sedimentary accumulation has created a diverse landscape characterized by beaches, marshes, and estuaries.