Zone : NP23

Age: EARLY OLIGOCENE

Stratigraphic remarks: The top of this zone is approximated by the first occurrence of common C. abisectus and top occurence of Sphenolithus speudoradians. The base by the top occurences of Isthmolithus recurvus and Reticulofenestra umbilica.

Zone : NP22

Age: EARLY OLIGOCENE

Stratigraphic remarks: The top of this zone is defined by the top occurrences of I. recurvus and R. umbilica and the base by the top occurrence of Ericsonia formosa.

Zone : NP21

Age: LATE EOCENE/EARLY OLIGOCENE

Stratigraphic remarks: This zone is defined by the top occurrence Ericsonia formosa and the base by the top occurrences of Cribrocentrum reticulatum and Discoaster saipanensis.

Zones: NP19/20

Age: LATE EOCENE

Stratigraphic remarks: The top of this 'combined' zone is defined by the top occurrences of Cribrocentrum reticulatum and Discoaster saipanensis and the base by the top occurences of Neococcolithes minutus/dubius.

Zones: NP17/18

Age: Early LATE to Late MIDDLE EOCENE

Stratigraphic remarks: The top of this 'combined zone' is defined by the top occurrence of Neococcolithus minutus/dubius and the base by the top occurrence of Chiasmolithus solitus.

Zone : NP16

Age: MIDDLE EOCENE

Stratigraphic remarks: The top ocurrence of this zone is defined by the top occurrence Chiasmolithus solitus and the base by the top occurences of Nannotetrina fulgens and Rhabdosphaera gladius.

Zone : NP15

Age: MIDDLE EOCENE

Stratigraphic remarks: The top of this zone is marked by the top occurrences of Nannotetrina fulgens and R. gladius and the base by the top occurence of Rhabdosphaera inflata and first occurence

of Nannotetrina fulgens.

Zones: NP13/14

Age: Early MIDDLE to Late EARLY EOCENE

Stratigraphic remarks: The top of this 'combined zone' is defined by the top occurrence of Rhabdosphaera inflata and the base by the top occurrence of Tribrachiatus orthostylus. The top occurrence of Discoaster lodoensis and D. kuepperi occur just above the Early/Middle Eocene boundary in the middle of the NP14zone. Imperiaster obscurus is used as a secondary marker for the base of the NP13 zone.

Zone : NP12

Age: EARLY EOCENE

Stratigraphic remarks: The top of this zone is defined by the top occurence of Tribrachiatus orthostylus and the base by the first occurrence of Discoaster lodoensis. The top occurrence of Sphenolithus primus is used as a secondary marker for the base of this zone. The top occurrence of I. obscurus approximates the top of this zone. The top occurrence of Micrantholithus mirabilis is used to split this zone into two subzones (PerchNielsen, 1985).

Zone : NN11

Age: EARLY EOCENE

Stratigraphic remarks: The top of this zone is defined by the first occurrence of Discoaster lodoensis and approximated by the top occurrence of Sphenolithus primus. The base of this zone marked by the top occurence of Tribrachiatus contortus and approximated by the first occurence of Tribrachiatus orthostylus.