Chalk Biozone 11 - Cassiculosphaeridia reticulata
Age: Mid Santonian to earliest Campanian.
Macrofaunal correlation: The upper U. socialis Zone to the lowermost O. pilula Zone.
Definition: The interval between the FAD of Cannosphaeropsis utinensis to the LAD of Cassiculosphaeridia reticulata.
Comments: Alternative indices for the top of this biozone are the LAD of Canningia senonica and the FAD of Palaeoglenodinium cretaceum (see Foucher, 1979).
Lithostratigraphical correlation: The Newhaven Chalk Formation (Southern Province), the Flamborough Chalk Formation (Northern Province) and the Mackerel Formation (North Sea).