The Fall Line is a low east-facing cliff paralleling
the Atlantic coastline from New Jersey to the Carolinas. It separates
hard
Paleozoic metamorphic
rocks of the Appalachian Piedmont to the west from the softer, gently
dipping
Mesozoic and
Tertiary sedimentary
rocks of the
Coastal Plain. This
erosional scarp, the site of many waterfalls, hosted flume- and
water-wheel-powered industries in colonial times and thus helped
determine the location of such major cities as Philadelphia, Baltimore,
Washington, and Richmond.
