Area: 0.24 hectares.
A Geological Conservation Review (GCR) site.
Description and Reasons for Notification:
Corton Cutting lies about 7 kilometres northwest of Weymouth and consists of a series of exposures in a short road cutting which provides access from the junction with the Upwey–Portesham road to Corton Farm.
Corton Cutting shows a section through the Portland Sand Formation of Late Jurassic (Tithonian) age. The upper part of the Formation is here remarkably developed, with lime mudstones, often rich in sponge spicules (‘spiculite’) yielding a rich marine fauna with serpulid encrusted oysters Nanogyra and ammonites (the latter representing the Albani Zone). These levels are taken to be equivalent to the Exogyra Bed of Ringstead and Portland and form the type sequence of the Corton Hill Member.
The overlying West Wear sandstone is dolomitised and indicates a sudden deepening, briefly reversing the overall trend of marine shallowing through the latest Jurassic. This is a nationally important site for study of the facies and stratigraphy of the Tithonian Stage in Britain.