Corallian Group

It is often found close to seams of Portland Limestone (e.g. Abbotsbury in Dorset, England).

A ridge of Corallian Limestone rises above the Vale of Avon and the Thames Valley in its Oxfordshire stretch.

The Oxfordshire Corallian ridge is an escarpment holding back the hanging valley that is the Vale of White Horse and its hardness forced the River Thames to take a wide northern detour, to cut through the low ridge at Oxford.

Softer sandy deposits occur within the Corallian, found for example at Faringdon, Shellingford and Hatford in Oxfordshire, where the sands and gravels are extensively quarried.

In England, Corallian Limestone is to be found in Dorset,[3] Wiltshire, Oxfordshire, Buckinghamshire, Cambridgeshire, Lincolnshire and Yorkshire.