Surface Sediments at 439 sites throughout the North Atlantic Ocean and adjacent seas have been analyzed for dinoflagellate cysts in oder to establish a reference database from which paleoenvironmental transfer functions can be developed. Laboratory procedures and systematics were standardized in order to avoid bias introduced by the selective loss of taxa and to facilitate site to site comparison. Data from 371 sites were retained to develop the database that includes 41 taxa, some of which were grouped using morphological andlor ecological criteria. Twentyseven taxa were retained for statistical purposes. Distribution maps of these latter taxa have been plotted on the basis of their relative abundance. Principal component analyses were performed in order to describe the distribution of assemblages. The relationship between the assemblages, as well as the relative abundance of individual taxa, and selected sea-surfaceparameters are illustrated. The Parameters which were considered include temperature and salinity for winter (February) and Summer (August) together with the duration of sea-ice cover. Transfer functions using the best analogue method have been tested with a view to reconstructing past sea-surface pararneters. Validation procedures on these transfer functions demonstrate that more than 95% of the reconstructions are included wi thin the interannal variability of modern sea-surface conditions. Therefore, these transfer functions give accurate results and can be applied in reconstructing paleotemperatures and paleosalinities from analogous assemblages in Quaternay sedimentary sequences. Protoperidinium stellatum (Wall in Wall & Dale 1968) Head, comb. nov. (basionym=Peridinium stellatum) is proposed herein, and Algidasphaeridium? minutum var. cewre de Vemal et al. 1989 ex de Vemal is newly validated.