Miocene Planktonic Foraminifera from Newport Bay California
AbstractTwenty species of planktonic foraminifera are reported from the Miocene Monterey Shale at Newport Bay, California. Rocks of the Luisian Stage contain numerous individuals and species; those of the overlying Mohnian Stage contain fewer species and individuals. Two local zones, recognized in the Luisian, are tentatively correlated with the lower Globorotalia f ohsi Assemblage Zone in Trinidad (Burdigalian). Higher parts of the Mohnian may correlate with the Helvetian. The classification adopted in this paper is based on the surface texture of the test. Forms with hispid tests ( spinose when living) are separated from smooth and pitted forms (non-spinose when living). This criterion has been utilized for distinguishing taxa at all systematic levels. Protentella gen. nov. (type species, P. prolixa sp. nov.) is described from the upper Luisian. Six new species are described: Turborotalia lata, Globigerina tecta, Protentella prolixa, and Globorotaloides trema from the Luisian; and Globigerina bramlettei and Eoglobigerina operta from the Mohnian.