Page 29 - History of Rockingham Co
P. 29
CHAPTER II.
GEOLOGICAL FEATURES OF ROCKINGHAM COUNTY.
BY
JUSTUS H. CLINE, M. A.,
Assistant Geologist, Virginia State Geological Survey.
On the basis of both geological and physiographic features
the state of Virginia is divided into three great provinces:
the Coastal Plain on the east, the Piedmont Plateau in the
central part, and the Appalachian Mountain province on the
w^est. Rockingham County lies entirely within the latter
province.
The Appalachian Mountain province is further divided
into three sub-provinces, each of which shows more or less
marked differences in the topographic types represented, the
Old Appalachians, or Blue Ridge, on the east; the Great Val-
ley, in the centre; and the New Appalachians, or Alleghany
Ridges, on the west. Each of the three subdivisions is well
represented within the borders of the county.
The topography of the county, in keeping with that of
the Appalachian Mountain province in general, is varied and
picturesque; and with the exception of the main part of the
Blue Ridge may be defined as the parallel ridge and valley
type; the ridges being generally parallel with each other and
extending in a northeast and southwest direction, in keeping
with the strike of the underlying rock-structure.
The Blue Ridge, which forms the eastern boundary of
the county, is distinct topographically from the rest of the
area in that it presents an uneven and knobby crest, and
shows an absence of the parallel ridge type in its main part,
which is so well developed both in the valley and the ridges
to the west. The foothills, or lower ridges, which flank the
Blue Ridge on its western slope, being made up of rocks sim-
ilar both in origin and structure to those of the west, partake
GEOLOGICAL FEATURES OF ROCKINGHAM COUNTY.
BY
JUSTUS H. CLINE, M. A.,
Assistant Geologist, Virginia State Geological Survey.
On the basis of both geological and physiographic features
the state of Virginia is divided into three great provinces:
the Coastal Plain on the east, the Piedmont Plateau in the
central part, and the Appalachian Mountain province on the
w^est. Rockingham County lies entirely within the latter
province.
The Appalachian Mountain province is further divided
into three sub-provinces, each of which shows more or less
marked differences in the topographic types represented, the
Old Appalachians, or Blue Ridge, on the east; the Great Val-
ley, in the centre; and the New Appalachians, or Alleghany
Ridges, on the west. Each of the three subdivisions is well
represented within the borders of the county.
The topography of the county, in keeping with that of
the Appalachian Mountain province in general, is varied and
picturesque; and with the exception of the main part of the
Blue Ridge may be defined as the parallel ridge and valley
type; the ridges being generally parallel with each other and
extending in a northeast and southwest direction, in keeping
with the strike of the underlying rock-structure.
The Blue Ridge, which forms the eastern boundary of
the county, is distinct topographically from the rest of the
area in that it presents an uneven and knobby crest, and
shows an absence of the parallel ridge type in its main part,
which is so well developed both in the valley and the ridges
to the west. The foothills, or lower ridges, which flank the
Blue Ridge on its western slope, being made up of rocks sim-
ilar both in origin and structure to those of the west, partake
