ABSTRACT

Mollusks and irregular echinoids are especially useful to field geologists in the eastern Gulf Coast region as indicators of stratigraphic position. Foraminifera and other microfossils are abundant in the geologic section and also are useful as stratigraphic markers, but are not easily identified and used in the field. Diagnostic species and distinctive assemblages of megafossils easily recognizable to geologists with limited knowledge of paleontology, are common in fossiliferous beds spaced at close stratigraphic intervals through the Paleocene and Eocene sequence. The most common, easily identified, widespread, and stratigraphically restricted are species of Ostreidae, Venericardia, Pectinidae, Crassatellidae, Turritellidae, and irregular echinoids. The most useful species have been selected for the names of sixteen assemblage and range zones distributed through the Paleocene and Eocene Series in the eastern Gulf Coast region.