These basins resulted from a regional rifting event that affected parts of North-West Europe, eastern North America and East Greenland.
[1] The oldest part of the sedimentary fill in the Worcester Basin is the Cisuralian (Early Permian) Bridgnorth Sandstone Formation, deposited in an aeolian environment.
Unconformably above this is the Early Triassic Kidderminster Formation of pebble conglomerates and sandstones, deposited in a fluvial environment.
The Triassic succession is completed by a thinly developed Rhaetian age Penarth Group sequence of marine mudstones.
[4] This fault runs along the east side of the Malvern Hills, which are themselves formed of Neoproterozoic and Lower Paleozoic rocks.