Atlantic Coastal Plain
One of the smallest provinces in the state and is confined to Philadelphia, Delaware, and Bucks counties along the Delaware River. Local relief is less than 200 feet (61 m) and much of the bedrock is buried under recent alluvial deposits. On the geologic map, "Trenton Gravel" is used to describe most of these sediments. However, much of the alluvial sediments that exist here are sand, silt, and clays. The traditional boundary of the coastal plain is the fall line. The coastal plain in Pennsylvania was once home to thousands of acres of fresh water tidal marsh. This was important in the early development of Philadelphia and Chester. Many of the small tributaries to the Delaware have cut small but impressive gorges into the bedrock including the Ridley Creek, the Chester Creek, and the Wissahickon Creek. Flash floods are becoming a local problem in the province.
Read more about this topic: Geology Of Pennsylvania
Famous quotes containing the words atlantic and/or plain:
“There was not a tree as far as we could see, and that was many miles each way, the general level of the upland being about the same everywhere. Even from the Atlantic side we overlooked the Bay, and saw to Manomet Point in Plymouth, and better from that side because it was the highest.”
—Henry David Thoreau (1817–1862)
“Are we not madder than those first inhabitants of the plain of Sennar? We know that the distance separating the earth from the sky is infinite, and yet we do not stop building our tower.”
—Denis Diderot (1713–1784)