The Cromer Forest Bed formation is exposed at intervals along the coast of Norfolk and Suffolk, from Weybourne to Kessingland. The forest bed was formed in the Quaternary Period and dates to between 780,000 and 450,000 years ago, within the Cromerian Stage of the Pleistocene. For many years the bed, named after the local town of Cromer, has been famous for its assemblage of fossil mammal remains, containing, for example, isolated bones and teeth, jaw bones, and the antlers of deer. Although most of the forest bed is now obscured by coastal defence, the Cromer Forest Bed continues to be eroded and is rich in fossils including the skeletal remains of the West Runton Mammoth which was discovered in 1990.
The sediments deposited precede those of the Anglian Stage and are on top of Beestonian Stage. Based upon the beginning of Marine Isotope Stage 21 and the end of Marine Isotope Stage 13, the Cromerian Complex started 866,000 years ago and ended 478,000 years ago.