Geoscience Reference
In-Depth Information
FIG
185.
The Thames Barrier. (Copyright Dae Sasitorn & Adrian Warren/
www.lastrefuge.co.uk)
AREA 10: THE COTSWOLDS TO READING
Area 10 straddles the main topographic and drainage divide of Southern England (Figs
186 and 187). About half of it is part of the Thames catchment and drains eastwards,
via London, to the North Sea, while its western areas form parts of the Bristol Avon and
Severn catchments, which drain into the Bristol Channel, and its southern part (Salis-
bury Plain) drains southwards towards the South Coast (Fig. 188).
The Area can be divided into four Landscapes based upon the presence of partic-
ular bedrocks immediately below the surface blanket (Figs 189 and 190). The large-
scale features of the bedrock pattern, as shown by the locations of the Chalk hills, have
already been explained in the general introduction to this Region. The more detailed
pattern has been created largely by river erosion, which has modified the gently slop-
ing limbs of the London Downfold and transported material to the east. In particular,
the locations of the Chalk Edges are entirely due to the interaction of earth movements
and landscape erosion over the past 60 million years, influenced especially by climate
change.
