Doubt remains concerning the age and nature of Late Cenozoic marine and glacial deposits along the coast of the Chukchi Peninsula, Siberia, and the correlation of these deposits with the Late Cenozoic sequence on nearby Alaskan coasts. A better understanding of the Chukotkan sequence is especially needed in the light of recent confirmation that western St. Lawrence Island was over-run by large glaciers that originated on the mountainous Chukchi Peninsula. Adding interest is the fact that glaciomarine deposits of middle Pleistocene age are reported to be widespread on the Chukchi coast. This award addresses these questions in a joint study with Soviet researchers intended to establish a new stratigraphic and geochronologic framework for regional late Cenozoic correlations. Special attention will be given to the paleoclimate significance of the remarkable mid-Pleistocene event that evidently resulted in out-of-phase glaciation throughout central Beringia. This project is proposed as a part of the program for U.S. - U.S.S.R. Cooperation in the Field of Basic Research.