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evidence of the transition from erosional hills and valleys, at the margin of the Var-
iscan uplands, to the basins of sediment deposition further east. Much local evidence
shows that the post-Variscan landscapes contained features oriented by variations in
resistance to erosion of the Variscan bedrock.
Close to places where this important surface can be examined today, the level low
in the New Red Sandstone often contains gravels and sands that, on subsequent burial
and cementing, have become strong enough to resist later erosion at the surface. There
are, therefore, many hills today resulting from the presence of strong New Red Sand-
stone sediments. These hills mimic the New Red Sandstone alluvial fans that earlier
extended into the basin.
Looking more widely around and across Southern England, the mapping of this
level allows us to pick out some broader features of the landscape not seen before.
Along the south coast of the Southwest this level has been traced below the sea, closely
following the present coastline, and then, in East Devon and Somerset, the general
trend of the surface turns abruptly northwards until it turns again to run westerly, form-
ing the floor of the Bristol Channel Basin. Subsiding movements represented by this
level show therefore that the Southwest Region was becoming a distinct upland in early
New Red Sandstone times.
Further north, the position of the basal New Red Sandstone level shows that sub-
siding movements were already starting to define not only the Bristol Channel but also
St George's Channel, the Worcester and Cheshire Basins and the uplifting Pennines
ridge, with the South Staffordshire and Warwickshire upfolds at its southern end (Fig.
316). This pattern makes it clear that the east-west trends south of the Variscan Front
are replaced by a very different movement pattern in the north.
Further east, in the East Anglian and Thames Valley Regions, the New Red Sand-
stone level is present below the surface, and helps to define the Midlands-London plat-
form below the later Mesozoic and Tertiary cover. The fact that the platform surface is
flat-lying, and generally at depths of only hundreds of metres, demonstrates the lack of
major vertical movements in this eastern part of Southern England since Permian and
Triassic times.
B: Middle Jurassic level
This is a very different sort of level, selected because it marks a widespread change
to limestone-accumulating conditions (most famously producing sediments that be-
came the Inferior Oolite) on the floor of the Middle Jurassic sea. This is important, in
present-day landscape terms, because the limestones form one of the main escarpment
features across the Southeast England Basin, particularly in the Severn Valley Region,
where they form the Cotswolds, and in the west of the East Anglian Region.
