DINOCYST DISTRIBUTIONS AND STRATIGRAPHY OF 2 CENOMANIAN-TURONIAN BOUNDARY (UPPER CRETACEOUS) SECTIONS FROM THE WESTERN ANGLO-PARIS BASIN

The dinoflagellate cyst distributions and stratigraphies of two repres entative Cenomanian/Turonian (C/T) boundary sections from the Maine an d Normandy regions of northern France are described. Siliciclastic-ric h sediments which characterize the Upper Cenomanian in Maine, contrast with the coeval nodular chalk and hardground lithofacies of Normandy. Both areas display a transition to marry chalks in the Lower Turonian . Dinocyst assemblages are characterized by low diversities (38 taxa) and low overall abundances, and relatively few stratigraphically signi ficant species. The continued occurrence of Epelidosphaeridia spinosa (Cookson & Hughes) Davey in the Upper Cenomanian of Maine is noted. Re sults are compared and contrasted with those from coeval sections else where in the Anglo-Paris Basin. A major decline in cyst abundance and diversity is typical of the C/T boundary interval, which is characteri zed by a dominance of tolerant cosmopolitan forms such as Circulodiniu m distinctum (Deflandre & Cookson) Jansonius, Hystrichosphaeridium bow erbankii Davey & Williams, Oligosphaeridium complex (White) Davey & Wi lliams, Odontochitina costata Alberti; emend. Clarke & Verdier and O. operculata (O. Wetzel) Deflandre & Cookson.