MOLLUSCAN EVIDENCE FOR A LATE PLEISTOCENE SEA-LEVEL LOWSTAND FROM MONTEREY BAY, CENTRAL CALIFORNIA

One hundred and twenty-three molluscan taxa are reported from four sam ples collected from a sea level lowstand deposit located between 100 m and 300 m below sea level in Monterey Bay, central California. Ecolog ical interpretations of these mollusks suggest temperatures essentiall y equivalent to those from Puget Sound, Washington, to southern Britis h Columbia; much cooler water than exists in Monterey Bay today; and w ater depths of about 10 to 50 m. Chlamys rubida from these deposits yi eld a C-14 age determination of about 17,000 yr B. P. This age is gene rally equivalent to a worldwide sea level lowstand between 20,000 and 15,000 yr B. P. of at least 100 m below modern sea level. The cooler a nd shallow-water aspect of the lowstand molluscan fauna is in full acc ord with the late Pleistocene paleogeography of Monterey Bay.