About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 37 (1953)

Issue: 12. (December)

First Page: 2781

Last Page: 2781

Title: California Lower Tertiary Foraminiferal Sequence.: ABSTRACT

Author(s): V. Standish Mallory

Article Type: Meeting abstract


A preliminary statement of the formal names proposed for the major divisions and subdivisions of a chronologic-biostratigraphic classification of the California Lower Tertiary, and a summary of the criteria on which each of these is based will be presented in this paper.

Evaluation of the faunal changes found in a complete stratigraphic sequence of foraminiferal faunas in the California Province has shown that this sequence of faunas resolves itself into six distinct major units of Stage magnitude which are differentiable throughout the California Province, and several units of Zonal magnitude which subdivide the Stagial units based upon the joint occurrences of species of Foraminifera.

The major subdivisions of the Paleocene are the Ynezian and Bulitan Stages constituting the oldest and next oldest Stages of the Tertiary. The Eocene subdivisions are the Juniperan Stage, Lower Eocene; the Middle Eocene Ulatisian Stage; and the two Upper Eocene Stages, the oldest, the Narizian, and the youngest, the Fresnian Stage.

The Zonal subdivisions of these Lower Tertiary Stages of the California Province are the Silicosigmoilina californica and Bulimina excavata Zones of the Ynezian Stage; the Bulimina bradburyi and Valvulineria wilcoxensis Zones of the Bulitan Stage; the Plectofrondicularia kerni and Alabamina wilcoxensis Zones of the Juniperan Stage; the Ulatisian Stage with three distinct Zones, only one of which, the uppermost Zone, the Amphimorphina californica Zone is named; the Uvigerina churchi and Uvigerina garzaensis Zones of the Narizian Stage; at least two Zones exist within the Fresnian Stage, but these are not named at the present time.

End_of_Article - Last_Page 2781------------

Copyright 1997 American Association of Petroleum Geologists