Geological Guide to Speeton

Speeton Clay (Right), Chalk and Red chalk (Middle), Glacial left

The Speeton Clay is part of the Aptian to Middle Albian from the Cretaceous. At Speeton the Speeton Clay formation is split into 4 beds, Bed A, B, C and D. Beds D Start from just past the Reighton Gap holiday camp past New Closes cliff, Beds C start from Black cliff up to Speeton Beck and Beds B and A start from Speeton Beck up to Red Cliff hole. The entire formation is usually slipped, so it is often very difficult to pinpoint any particular horizon without finding the relevant fossils.

The Speeton Clay Formation comprises of mudstones, cementstones and sporadic bentonites. It was divided into five units by Lamplugh [1889] and this division is still maintained. E Bed: the basal bed comprises rolled and fragmented, pyritized and phosphatized bivalves, ammonites and bone and is usually referred to as the Copralite Bed. D Beds: black shale is overlain by greenish-brown, brown and grey clays and includes The Blue Bed [D6], The Lingula Bed [D5] and The Astarte Bed [D4]. A compound nodular bed [Bed D1] occurs at the top of the D beds.

Further south-east and you will come to a small outcrop of Red Chalk, followed by the chalk. There are also some good sections of glacial material just after the clay.