This site comprises a section of river just east of Netherfield in East Sussex which cuts through a lithologically varied sequence of Purbeck Beds, including marine horizons.
The section exposed runs from the Blues Limestones through the Plant and Bone Beds, the Cinder Bed, Arenaceous Beds, the Shales-with-Ironstone to the Greys Limestone. Such a section is unrivalled in Sussex. The correlations of the Purbeck Beds of Sussex with those of the type seen in Dorset and elsewhere in southern England is disputed since analysis of fossilised spores within the rock indicates that these are considerably younger than beds in Dorset; with most of the section post-dating the better known Purbeck Beds of more westerly areas. Evidence provided by ostracods, fossil crustaceans, much more tied to the time and environment of emplacement than spores, and lithological similarities contradict this correlation; this has given rise to a great deal of questions srounding this important exposure. and has led to these sections being values of great importance in studies of late Jurassic to early Cretaceous environments and correlations.