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A palynological investigation of the Upper Jurassic Kimmeridge Clay in its type area (Dorset, southern England) identified twenty-five stratigraphically useful dinoflagellate cyst datums (range tops and bases). These have enabled the Kimmeridgian dinoflagellate cyst zonation of Woollam and Riding (1983) to be substantially refined. Eleven subzones are established within Woollam and Riding's Gonyaulacysta jurassica -Scriniodinium crystallinum (Gj/Sc), Scriniodinium luridum (SI) and Glossodinium dimorphum -Dingodinium tuberosum (Gd/Dt) zones, which span part of the Oxfordian and the entire Kimmeridgian stages. The indices of these zones, and the overlying Ctenidodinium culmulum -Ctenidodinium panneum (Cc/Cp) Zone, are amended and their definitions revised.The dinoflagellate cyst floras are broadly comparable to others from northern Europe, but show certain differences with coeval Tethyan assemblages. Two new skolochorate dinoflagellate cyst species are described, Oligosphaeridium patulum sp. nov. and Systematophora daveyi sp. nov.

Synopsis The Staffin Bay and Staffin Shale formations of Trotternish, Skye represent an important Middle–Upper Jurassic (Callovian–Kimmeridgian) reference section. The succession is 133 m thick, mudstone-dominated, and the Staffin Shale Formation is rich in zonal ammonite faunas. Both formations have yielded abundant palynofloras rich in marine microplankton. The Staffin Bay Formation is lowermost Callovian on both dinoflagellate cyst and regional evidence. Only one ammonite has been recorded from its uppermost division, the Belemnite Sands Member. Miospores dominate the Staffin Bay Formation and the relatively low diversity dinoflagellate cyst floras are consistent with a palaeoenvironmental interpretation of restricted, nearshore marine conditions. Dinoflagellate cysts and other marine microplankton are relatively abundant and diverse throughout the Middle Callovian to Lower Kimmeridgian Staffin Shale Formation, thereby indicating an open marine depositional setting. The stratigraphical distributions and relative proportions of the dinoflagellate cysts are largely consistent with those observed in England and elsewhere in northern Europe. Established dinoflagellate cyst zonal schemes can be applied to both formations. Certain species, however, exhibit minor stratigraphical differences in overall ranges. Wanaea acollaris Dodekova 1975, for example, is recorded in the Lower Oxfordian Dunans Clay Member (Staffin Shale Formation); the range top of this species was previously thought to be within the Upper Callovian. Certain species recorded in the Staffin Shale Formation are interpreted as being of Boreal affinity; these include Ambonosphaera? staffinensis ( Gitmez 1970 ) Poulsen & Riding 1992 , Paragonyaulacysta spp. and Gonyaulacysta dentata ( Raynaud 1978 ) Lentin & Vozzhenikova 1990.

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