Stratigraphic Significance of Two Genera of Tertiary Calcareous Nannofossils

Abstract

A new species of calcareous nannoplankton Ceratolithus rugosus is described, and emended descriptions of two other species of this genus are presented. The worldwide occurrence and partial overlap in the sequence of ranges of these taxa are helpful in age assignment of late Miocene to Holocene strata. A new species Peritrachelina joidesa of late Eocene to middle Oligocene age is also described.