During all these millions of years of sea level rise and fall, land
to the west was eroding and sediments were being carried eastward to
the sea and deposited. These marine sediments built up to great
depths over the bedrock. The marine sediments in Washington County
are 2,500 feet or more thick. The landscape of the county reflects
its marine history. The landforms of Washington County were shaped
by the same forces at work today on the Outer Banks and on the sea
bottom.
During times when the land was not covered by the sea, some of the
sediments were moved and redeposited by streams and by wind. The
rivers laid down deposits of sediments that are now called river
terraces. River terraces parallel the river and become higher and
older as the distance from the river increases. Each terrace is
typically fronted by a sand ridge, deposited by the river as a
natural levee when the river overflowed. Natural levees form when
streams overflow their banks and the sediment-carrying capacity of
the flowing water decreases. The heaviest materials and the ones
that drop out first are the sands, forming sand ridges on the stream
banks. Plymouth is built on a series of old river terraces that were
deposited by the Roanoke River over many years. The town rises in
steps as the distance from the river increases. An excellent example
of an older levee is the sand ridge on the north side of Third
Street where the old Baptist cemetery is located. The Latham House
is also located on an old levee. Roanoke Shores and the Weyerhaeuser
Paper Mill are built on the present natural levee of the Roanoke
River. The land around Plymouth is a complex mix of river deposits
and remnant dunes. Rolling Pines is built on an old dune field. The
sand ridges along Mackeys Road were dunes formed off the old Roanoke
River, and the sand ridges along Newland Road near Cherry are dunes
that formed along the Scuppernong River. In general, these old dunes
are the highest points around. Mountain Canal at Lake Phelps got its
name from the large dune it cuts through.
The older marine sediments are responsible for the springs and
artesian wells that were a part of Washington County's early
history. "Cool Springs" near Plymouth was named for its springs.
In addition, by some accounts, the original name for Creswell was "Cool Springs". Artesian wells or springs occur when an aquifer
under an impervious layer of rock or clay is recharged at a higher
elevation. This causes the water to be under enough pressure to
force it to the ground surface. Artesian wells existed in downtown
Plymouth until relatively recent; ceasing to flow as pumping by the
town and other users relieved the artesian pressure.