1. Surficial geologic map of part of the Allentown 30ʹ x 60ʹ quadrangle, Berks, Bucks, Carbon, Lehigh, Luzerne, Monroe, Northampton, and Schuylkill counties, Pennsylvania [microform] Yale Public content 1993. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). U.S. Geological Survey ; Books and Open-File Reports Section, distributor. English. Public. Pennsylvania and Allentown Region.