Six recognizable species and numerous fragments of dinoflagellates are present in the upper Cornbrash (Jurassic) sandy limestone at Cayton bay, south of Scarborough. Three new species of Gonyaulax, Pareodinia prolongata n.sp., and the new variety P. ceratophora pachyceras are identified and described. A small number of hystrichospheres is also present, in which three new species are represented--Baltisphaeridium varispinosum, Cymatiosphaera parva, and Pterospermopsis helios.