Page 31 - History of Rockingham Co
P. 31
A HISTORY OF
flowing or have flowed in a former period. The valleys be-
tween the ridges are narrow.
The drainage of Rockingham county belongs entirely to the
Shenandoah system. The two master streams are the North
Fork, which flows west of the Massanutten Mountain, and
the main part of the Shenandoah, which flows through the
Page valley east of the same mountain. These streams and
their tributaries have cut the Shenandoah plain into a deep
intaglio, and they now flow in channels from 100 to 300 feet
below it. The streams of the county have for the most part
adjusted themselves to the underlying structural conditions,
and consequently they tend to flow in a northeasterly direction.
The chief exception to this is the North River, which flows
eastward near the southern border of the county. This
stream, instead of flowing parallel with the strike of the rock
formations, takes a course at right angles to the strike and
maintains it till its influx with the main Shenandoah near the
foot of the Blue Ridge. This is explained by the fact that its
course antedates the folding of the rock strata which has oc-
curred in the Appalachian province. The county is exceed-
ingly well watered, and springs of large size are frequent.
The rocks of the county fall under the two great lithologic
types, igneous and sedimentary. Both types occur in all
three of the sub-provinces. It is understood that igneous
rocks are those which have solidified from a molten condition,
while the sedimentaries are those which are composed of
material derived from the waste of land and redeposited in
the form of mud, sand, gravel, chemical precipitants, etc.
chiefly in lakes and seas.
The only dominantly igneous area in the county is the
main part of the Blue Ridge. The formations of the rest of the
county are sedimentary, with very minor exceptions. Cer-
tainly less than one per cent, of the rocks of the county which
outcrop at the surface are of igneous origin, and all these
with the few noted exceptions are entirely in the Blue Ridge.
The igneous rocks of the Blue Ridge in Rockingham
County are of the basaltic type, which represent material
—24—
LIBRARY ^,
W-r.T VmOiNlA UNIVERSITT
flowing or have flowed in a former period. The valleys be-
tween the ridges are narrow.
The drainage of Rockingham county belongs entirely to the
Shenandoah system. The two master streams are the North
Fork, which flows west of the Massanutten Mountain, and
the main part of the Shenandoah, which flows through the
Page valley east of the same mountain. These streams and
their tributaries have cut the Shenandoah plain into a deep
intaglio, and they now flow in channels from 100 to 300 feet
below it. The streams of the county have for the most part
adjusted themselves to the underlying structural conditions,
and consequently they tend to flow in a northeasterly direction.
The chief exception to this is the North River, which flows
eastward near the southern border of the county. This
stream, instead of flowing parallel with the strike of the rock
formations, takes a course at right angles to the strike and
maintains it till its influx with the main Shenandoah near the
foot of the Blue Ridge. This is explained by the fact that its
course antedates the folding of the rock strata which has oc-
curred in the Appalachian province. The county is exceed-
ingly well watered, and springs of large size are frequent.
The rocks of the county fall under the two great lithologic
types, igneous and sedimentary. Both types occur in all
three of the sub-provinces. It is understood that igneous
rocks are those which have solidified from a molten condition,
while the sedimentaries are those which are composed of
material derived from the waste of land and redeposited in
the form of mud, sand, gravel, chemical precipitants, etc.
chiefly in lakes and seas.
The only dominantly igneous area in the county is the
main part of the Blue Ridge. The formations of the rest of the
county are sedimentary, with very minor exceptions. Cer-
tainly less than one per cent, of the rocks of the county which
outcrop at the surface are of igneous origin, and all these
with the few noted exceptions are entirely in the Blue Ridge.
The igneous rocks of the Blue Ridge in Rockingham
County are of the basaltic type, which represent material
—24—
LIBRARY ^,
W-r.T VmOiNlA UNIVERSITT
