Rowe (1900) - Micraster cortestudinarium Zone
Biostratigraphical correlation: Equates with the upper S. plana Zone, and a variable interval from within the top of the M. cortestudinarium Zone to the basal M. coranguinum Zone, of current usage. Rowe was inconsistent in his recognition of the top of this zone in different sections, selecting levels at the Light Point / Beachy Head Beds, Shoreham Marl 2 (the currently accepted definition of the top of the zone) and within the Belle Tout Beds (Wood, WH/95/31R).
Lithostratigraphical correlation: Equates with the upper Lewes Nodular Chalk Formation and, depending on how the top of the zone is defined, also the basal part of the Seaford Chalk Formation of southern England.
Age: Late Turonian & Early Coniacian.