1. Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian Basin from Lake County, Ohio, to Juniata County, Pennsylvania Yale Public content 1992. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Map Distribution. English. Public. Appalachian Basin. Cambrian and Ordovician.