1. Bedrock geologic map of the Egremont quadrangle and adjacent areas, Berkshire County, Massachusetts, and Columbia County, New York Yale Public content 1971. 2012-11-02T19:46:19Z. 2012-11-02T19:46:19Z. Zen, E-an, 1928-. U.S. Geological Survey. English. Public. Massachusetts, Berkshire County, New York (State), and Columbia County.