Atlantic Seaboard Fall Line

Escarpment in the Eastern United States Atlantic Seaboard fall lineEscarpmentMap showing part of the Eastern Seaboard Fall Line, where the pale-colored coastal plain meets the brightly colored PiedmontLocationUnited StatesFormed byNew Jersey, Virginia, the Carolinas, Georgia, Alabama, U.S.Dimensions • Length900 mi (1,400 km) The Atlantic Seaboard Fall Line, or Fall Zone, is a 900-mile (1,400 km) escarpment where the Piedmont and Atlantic coastal plain meet in the eastern United States. Much of the fall line passes through areas where no evidence of faulting is present. Description The fall line marks the geologic boundary of hard metamorphosed terrain—the product of the Taconic orogeny—and the sandy, relatively flat alluvial plain of the upper continental shelf, formed of unconsolidated Cretaceous and Cenozoic sediments. Examples of fall zone features include the Potomac River's Little Falls and the rapids in Richmond, Virginia, where the James River falls across a series of rapids down to its tidal estuary. Before navigation improvements, such as locks, rapids or waterfalls along the fall line were generally the head of navigation on rivers and necessitated portage around th