The Clent Hills are a major outcrop of the Clent Formation consisting of Clent Breccia (predominantly a red-brown mudstone matrix) dating from the early part of the Permian period. The formation unconformably overlies the mudstones and sandstones of the Salop Formation which forms the lower ground to the north and east; both are assigned to the Warwickshire Group. The bedrock is cut by numerous faults, most of which are aligned NE-SW.