Contents

03 October 1975
Vol 190, Issue 4209

About The Cover

Varved sediments of glacial Lake Hitchcock in an abandoned brickyard in Willimansett, Massachusetts. Each varve represents 1 year of lake-bottom deposition consisting of a summer layer of silt and sand and a winter layer of clay. One hundred and thirty varves are exposed at this site. See page 48. [K. L. Verosub, University of California, Davis]