Dinoflagellate cysts are abundant and diverse in the Eocene of southern England, with many species having restricted stratigraphic ranges. Thirteen dinoflagellate cyst assemblage zones are formally proposed, three in the London Clay, five in the Bracklesham Beds, and five in the Barton Beds. Five genera and twenty species of dinoflagellate cysts are erected, generic transfers are made for sixteen species, and the diagnoses of six genera and four species are emended. One genus and two species of acritarchs are also erected. The new genera are Cerebrocysta, Dapsilidinium, Hemisphaeridium, Lentinia, Paucisphaeridium, and Quadrina.