Griffith & Brydone (1911); Brydone (1912) - Micraster cortestudinarium Zone
Biostratigraphical correlation: Equates with an interval from within the top of the S. plana Zone to about a third of the way up the M. coranguinum Zone of current usage. Griffith & Brydone (1911) expanded the concept of the M. cortestudinarium Zone to include strata below the range of the index of the next youngest zone (i.e. strata below the range of Micraster coranguinum).
Lithostratigraphical correlation: Equates with the upper part of the Lewes Nodular Chalk Formation and the lower part of the Seaford Chalk Formation of southern England.
Age: Latest Turonian & Coniacian