United States: The East and the Gulf Coast

The East and the Gulf Coast

The Atlantic–Gulf Coastal Plain extends along the east and southeast coasts of the United States from E Long Island to the Rio Grande; Cape Cod and the islands off SE Massachusetts are also part of this region. Although narrow in the north, the Atlantic Coastal Plain widens in the south, merging with the Gulf Coastal Plain in Florida. The Atlantic and Gulf coasts are essentially coastlines of submergence, with numerous estuaries, embayments, islands, sandspits, and barrier beaches backed by lagoons. The northeast coast has many fine natural harbors, such as those of New York Bay and Chesapeake Bay, but south of the great capes of the North Carolina coast (Fear, Lookout, and Hatteras) there are few large bays. A principal feature of the lagoon-lined Gulf Coast is the great delta of the Mississippi River.

The Atlantic Coastal Plain rises in the west to the rolling Piedmont (the falls along which were an early source of waterpower), a hilly transitional zone leading to the Appalachian Mountains. These ancient mountains, a once towering system now worn low by erosion, extend southwest from SE Canada to the Gulf Coastal Plain in Alabama. In E New England, the Appalachians extend in a few places to the Atlantic Ocean, contributing to a rocky, irregular coastline. The Appalachians and the Adirondack Mountains of New York (which are geologically related to the Canadian Shield) include all the chief highlands of E United States; Mt. Mitchell (6,684 ft/2,037 m high), in the Black Mts. of North Carolina, is the highest point of E North America.

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