Calcareous Nannofossils of the Louisiana Continental Shelf: Additions and Corrections

Abstract

In a recent paper (Sachs and Skinner, 1973a), the first occurrence of the placolith Gephyrocapsa caribbeanica Boudreaux and Hay on the Louisiana Continental Shelf was used as one of the bases for recognition of the Pliocene-Pleistocene boundary in this area. The base of the early Pleistocene Terrebonne Shale (interpreted as Zone N. 22) lies a short distance below the first observed Gephyrocapsa caribbeanica (rare, 1 to 5 specimens per traverse) and the first abundant occurrence of the planktonic foraminifer Globorotalia truncatulinoides (d'Orbigny) in the strata beneath the Louisiana Continental Shelf.