+ approximate age in millions of years.
* includes the Huntingbridge and Elmore Beds.
1 this division of the Headon Hill Formation includes the following Members: Seagrove Bay, Osborne Marls, and Fishborne.
2 this division of the Headon Hill Formation includes the following Members: Lacey’s Farm, Cliff End, Hatherwood Limestone, and Linstone Chine.