A suite of 17 box core samples taken along an onshore-offshore transect across the southern California continental borderland representing Tanner, Santa Monica, San Pedro, Santa Catalina, and San Nicolas basins were analyzed for palynomorph content. Dinoflagellate cysts, acritarchs (organic-walled phytoplankton), and spores and pollen of terrestrial plants are present in all samples. Dinoflagellate cysts and acritarchs are more common in samples from Santa Monica and San Pedro basins, and show a general decrease in abundance with increasing distance from shore. Cyst genera include Leptodinium, Lingulodinium, Nematosphaeropsis, and Spiniferites (referrable to the thecate genus Gonyaulax) and species of Peridinium. Lingulodinium machaerophorum Deflandre and Cookson (= Gonyaulax polyedra Stein) is the dominant species in all samples. Spores, pollen, and other plant tissue fragments provide an indication of the terrestrial component of these sediments.
Evidence of reworking of older material into recent sediments is suggested by differential stain uptake observed among individual specimens of phytoplankton and pollen.