Gaster (1924, 1927, 1929, 1932, 1937, 1941, 1944) - Holaster subglobosus Zone
Biostratigraphical correlation: Equates with the A. rhotomagense Zone, A. jukesbrownei Zone, C. guerangeri Zone and M. geslinianum Zone (pars) of current usage.
Lithostratigraphical correlation: Equates with the Zig Zag Chalk Formation and basal Holywell Nodular Chalk Formation of southern England.
Subzone: Actinocamax plenus Subzone
Age: Mid to Late Cenomanian