Page 39 - History of Rockingham Co
P. 39
A HISTORY OF
beds are rarely found in this position, but have been folded
into anticlines and synclines and frequently broken by great
overthrust faults and also by simple gravity faults.
Since the folding and faulting of the region, erosion has
been active, so that now the mountain ridges frequently oc-
cupy the position of the synclines, as in the case of the Mas-
sanutten mountain; and the river valleys in the same way oc-
cupy the position of the anticlines. The Valley province is
not a structural valley, but it is entirely the product of erosion.
The material which once occupied its position, being less re-
sistant to the forces of degradation, was disintegrated by
chemical and mechanical forces and carried by the streams to
the sea. The streams which have been responsible for this
work have suffered likewise many changes, and now in a
small measure only resemble their early ancestors. The
drainage of the county at the beginning of the long cycle of
erosion which developed its present land forms seems to have
been controlled by two master streams. One of these streams
occupied a position similar to North River, in the latitude of
Bridgewater, and the other a position similar to the North
Fork, in the latitude of Brock's Gap; the North River flowing
across the Valley and Blue Ridge, possibly through Brown's
Gap, and the North Fork across the Valley and the Massan-
utten Mountain at New Market and the Blue Ridge opposite
Luray. Since the limestones of the Valley were more easily
eroded than the harder rocks of the Blue Ridge, and since the
Potomac came to be the master stream because of its size,
tributaries of the Potomac flowing northward over the soft
rocks of the valley were finally able to intercept these streams,
first the North Fork at Luray and later the North River at
Port Republic. Subsequently to these captures the Valley has
been lowered many hundred feet below its level at the time
the captures took place.
The limestones of the Valley province are responsible for
the numerous beautiful limestone caverns and bold springs
which are so common, as well as for the remarkable fertility
of the soils of the county, v/hich has made her one of the
-30-
beds are rarely found in this position, but have been folded
into anticlines and synclines and frequently broken by great
overthrust faults and also by simple gravity faults.
Since the folding and faulting of the region, erosion has
been active, so that now the mountain ridges frequently oc-
cupy the position of the synclines, as in the case of the Mas-
sanutten mountain; and the river valleys in the same way oc-
cupy the position of the anticlines. The Valley province is
not a structural valley, but it is entirely the product of erosion.
The material which once occupied its position, being less re-
sistant to the forces of degradation, was disintegrated by
chemical and mechanical forces and carried by the streams to
the sea. The streams which have been responsible for this
work have suffered likewise many changes, and now in a
small measure only resemble their early ancestors. The
drainage of the county at the beginning of the long cycle of
erosion which developed its present land forms seems to have
been controlled by two master streams. One of these streams
occupied a position similar to North River, in the latitude of
Bridgewater, and the other a position similar to the North
Fork, in the latitude of Brock's Gap; the North River flowing
across the Valley and Blue Ridge, possibly through Brown's
Gap, and the North Fork across the Valley and the Massan-
utten Mountain at New Market and the Blue Ridge opposite
Luray. Since the limestones of the Valley were more easily
eroded than the harder rocks of the Blue Ridge, and since the
Potomac came to be the master stream because of its size,
tributaries of the Potomac flowing northward over the soft
rocks of the valley were finally able to intercept these streams,
first the North Fork at Luray and later the North River at
Port Republic. Subsequently to these captures the Valley has
been lowered many hundred feet below its level at the time
the captures took place.
The limestones of the Valley province are responsible for
the numerous beautiful limestone caverns and bold springs
which are so common, as well as for the remarkable fertility
of the soils of the county, v/hich has made her one of the
-30-
