Middle Tertiary Calcareous Nannoplankton of the Cipero Section, Trinidad, W. I.

Abstract

The middle Tertiary calcareous nannoplankton in the Cipero section of Trinidad are described, and their distribution in the samples from the foraminiferal zones of Bolli shown. From these data a zonation based on the calcareous nannoplankton is indicated. Some correlations with strata elsewhere, using these zones, are suggested. Of the genera two are new: Orthorhabdus and Orthozygus. Of the 52 described species 16 are new: Cyclococcolithus neogammation, Helicosphaera ampliaperta, Helicosphaera compacta, Helicosphaera obliqua, Helicosphaera parallela, Helicosphaera truncata, Staurolithites minutus, Discoaster adamanteus, Discoaster extensus, Discoaster tani ornatus (n. subsp.), Orthorhabdus serratus, Sphenolithus belemnos, Sphenolithus ciperoensis, Sphenolithus predistentus, Sphenolithus pseudoradians, and Triquetrorhabdulus rugosus.