In
the northwest corner of the state is the Ridge and Valley
province which is characterized by many long, parallel valleys and
ridges that resulted from erosion of folded sedimentary rocks.
The
Blue Ridge province is the southwestern end of the Appalachian
Mountains, and is underlain by hard crystalline rock. It is an area
of forested mountains and valleys, with elevation ranging from less
than 1000 ft. to 4784 ft at Brasstown Bald, Georgia's highest point.
The
Piedmont province is an area of rolling plains underlain
by the same hard crystalline rocks as the Blue Ridge but without
the high mountains and steep topography. It comprises nearly one-third
of the state. The soils are sandy loam and clay loam and support
a variety of agricultural crops, including cotton, corn and peaches.
The
Coastal Plain province is the largest, over sixty percent
of the state. It is underlain by sand and limestone which, combined
with this province's relatively flat topography, produces little
runoff of rainwater because most of it readily soaks into the sandy
soil.
The
Fall Line is the dividing line between the Piedmont and the
Coastal Plain. It is the landward boundary of encroachment by the
ocean during the Cretaceous period when sea level was much higher
than it is today. The Fall Line gets its name from the many waterfalls
and rapids that occur along it, created by rivers running from the
Piedmont with its relatively hard, erosion-resistant metamorphic
rocks into the Coastal Plain with its relatively soft and erodable
sedimentary rocks. Rivers above the Fall Line typically have narrow
or non-existent floodplains, while rivers below the Fall Line are
characterized by wide floodplains, adjacent marshes and meandering
streambeds.
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