Sediment sources and Palaeozoic history of the Bristol Channel area

Lithological and palaeocurrent data across South Wales from sediments of late Precambrian to late Silurian age, inclusive, indicate persistent derivation from a land source of Precambrian rocks in what is now the Bristol Channel area and southwards over Cornubia. In contrast to southern Wales, there is no evidence for Lower Palaeozoic deposition across most of the region to the south of the Bristol Channel; this land area is here named Pretannia. Early Devonian southward progradation of Old Red Sandstone facies terminated the long period of non- deposition across Pretannia. Later Palaeozoic tectonic movements in the Bristol Channel region led to the intermittent exhumation of the northern fringe of the landmass.