NEW UPPER PALEOCENE SPECIES OF THE BIVALVE PLICATULA FROM SOUTHERN CALIFORNIA

Three new species of the shallow-marine, warm-water bivalve Plicatula are reported from the upper Paleocene Santa Susana Formation of southe rn California. Plicatula simiensis new species is from the middle part of the formation on the south side of Simi Valley and occurs as a dis placed specimen in deep-marine turbidites. Plicatula lapidicina new sp ecies and P. trailerensis new species are both from coralline-algal-ri ch muddy siltstone just beneath a nearshore, coralline-algal limestone interval in the upper part of the formation in the Santa Ynez Canyon area east-central Santa Monica Mountains. These three new species repr esent the first late Paleocene records of genus Plicatula on the west coast of North America and the first Paleocene records of this genus i n southern California.