Cretacoeus planktonic foraminifera from Exmouth Plateau, Australia

Twelve zones and two subzones are recognized. The Albian and Cenomanian zones, currently only three, can probably be subdivided into several more.

The ranges of the Tethyan index species Globotruncana ventricosa and Globotruncanita elevata are discussed and found to differ from the ones usually given in standard zonal schemes. The planktonic foraminiferal succession is interpreted as a mid-latitude one in which the Tethyan influence started suddenly in the late Albian and then fluctuated throughout the Late Cretaceous, with a long low-diversity interval during the Campanian to middle Maestrichtian.