Planktic Foraminifera and Calcareous Nannoplankton Biostratigraphy of the Neogene of Mexico Part II- Lower Pliocene

Abstract

Six outcrop localities in the Isthmus of Tehuantepec, Mexico, are assigned to the Lower Pliocene Zones N. 18 or N. 19 on the basis of concurrent range zones of planktic foraminifera and calcareous nannofossils. Beds at one of the localities have been referred to the Encanto "Formation" by Mexican geologists. Microfossil lists for the localities follow the taxonomic procedures of Kennett and Srinivasan (1983) or Haman et al. (1980), differing only when inconsistent with the experience or interpretations of this writer. Illustrations have been included for taxa that were not identified from the Middle Pliocene of Mexico in this series (Akers, 1979).