1. Isopleth maps showing regional variations in pH of stream water and ground water in relation to geologic setting and known mineral deposits, Glens Falls 1⁰ x 2⁰ quadrangle, New York, Vermont, and New Hampshire Yale Public content 1991. 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. New York (State), Glens Falls Region, Vermont, and New Hampshire.