Gonioteuthis quadrata gracilis Zone
Base: In both the European standard and English successions, the base of the zone is recognised by the first occurrence of the index species (Christensen, 1991).
Range of index species: In both the European standard and English successions, the range of the index species is from the base of the nominate zone to the top of the overlying G. quadrata gracilis / B. mucronata Zone (Christensen, 1991).
Biostratigraphical correlation: The zone equates with an interval within the higher part of the G. quadrata Zone (lower part of 'post Applinocrinus beds') of the standard macrofossil zonal scheme for the UK Chalk Group (Christensen, 1991).
Lithostratigraphical correlation: The zone can be inferred to equate with the top of the Culver Chalk Formation and basal part of the Portsdown Chalk Formation of southern England.
Age: Campanian (Christensen, 1991).