1. Quaternary geologic map of the Chesapeake Bay 4⁰?x 6⁰ quadrangle, United States Yale Public content 1987. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). U.S. Geological Survey ; For sale by Map Distribution. English. Public. Middle Atlantic States. Quaternary.