"Appalachian Basin" . . "From 425 to 570 million years ago" . . "Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian Basin from Lake County, Ohio, to Juniata County, Pennsylvania"@en . . . . . . "Charts, diagrams, etc"@en . . "Stratigraphic framework, Cambrian and Ordovician rocks, central Appalachian Basin, Ohio to Pennsylvania"@en . . . . . . . . . . "Cambrian and Ordovician rocks in the central Appalachian Basin from Lake County, Ohio, to Juniata County, Pennsylvania"@en . . . . . . "Maps"@en . . . .