l description of England
and Wales according to natural regions, which usually follow the geology
of the country very closely; although the relationship of configuration
and geology is not so simple or so clearly marked as in Scotland.
The land is highest in the west and north, where the rocks also are
oldest, most disturbed, and hardest, and the land surface gradually
sinks towards the east and south, where the rocks become successively
less disturbed, more recent, and softer. The study of the scenery of
England and Wales as a whole, or the study of orographical and
geological maps of the country, allows a broad distinction to be drawn
between the types of land-forms in the west and in the east. This
distinction is essential, and applies to all the conditions of which
geography takes account. The contrasted districts are separated by an
intermediate area, which softens the transition between them, and may be
described separately.
The Western Division is composed entirely of Archaean and Palaeozoic
rocks, embracing the whole range from pre-Cambrian up to Carboniferous.
The outcrops of these rocks succeed each other in order of age in
roughly concentric belts, with the Archaean mass of the island of
Anglesey as a centre, but the arrangement in detail is much disturbed
and often very irregular. Contemporary igneous outbursts are extremely
common in some of the ancient formations, and add, by their resistance
to atmospheric erosion, to the extreme ruggedness of the scenery. The
hills and uplands of ancient rocks do not form regular ranges, but rise
like islands in four distinct groups from a plain of New Red Sandstone
(Permian and Triassic), which separates them from each other and from
the newer rocks of the Eastern Division. Each of the uplands is a centre
for the dispersal of streams; but with only one prominent exception (the
Humber) these reach the sea without crossing into the Eastern Division
of the country.
The Eastern Division, lying to the east of the zone of New Red
Sandstone, may be defined on the west by a slightly curved line drawn
from the estuary of the Tees through Leicester and Stratford-on-Avon to
the estuary of the Severn, and thence through Glastonbury to Sidmouth.
It is built up of nearly uniform sheets of Mesozoic rock, the various
beds of the Jurassic lying above the New Red Sandstone (Triassic), and
dipping south-eastward under the successive beds of the Cretaceous
system. In exactly the same
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