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Planktonic Foraminifera are present in abundance in the middle to upper Miocene (upper Luisian and lower Mohnian) Monterey Shale exposed at Newport Bay, California. About 20 species of planktonic Foraminifera are tentatively recognized. The greatest number of species and individuals occur in the upper Luisian, including species of Globigerina, Globoquadrina venezuelana, Orbulina suturalis, and Globigerinoides trilobus. In the uppermost Luisian, just below the Luisian-Mohnian boundary, is a local zone characterized by Hastigerina (Bolliella) sp. nov. which may prove useful in regional correlation. Species and individuals are less numerous in the lower Mohnian, although Globigerina bulloides, G. pachyderma, and Globoratalia scitula are present. During the time represented b these rocks species of planktonic Foraminifera were not as numerous at Newport Bay as in tropical areas where the standard planktonic reference sections were defined. Thus correlation to these areas is not yet established.
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