Earth’s geological structure and processes - Fundamentals of the Physical Environment - page 223

Plate 10.7 The Welsh landform seen in a Landsat thematic mapper image 180 km wide, bands 4, 5 and 7. This may be used
in conjunction wit h Figure 10.22 to identify the strong links between geological structure, lithology and landform. In particular, the
highest relief in North Wales is associated with volcano-tectonic structures; north-east-south-west Caledonian structures
dominate the Welsh basin, forming central upland Wales between major fracture zones in the north-west and south-east; and
Upper Palaeozoic and younger rocks form the south-eastern rim to the basin, seen best in the Brecon Beacons and North Crop
of the South Wales coalfield (south centre). The Variscan front was almost east-west across the south coast.
Image: British Geological Survey