1. Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian basin from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, West Virginia Author/Creator: Ryder, Robert T. Publication/Creation: [Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, 2003 Resource Type: Book Edition: Version 2.0. Access & Availability: Loading
2. Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian basin from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, West Virginia Author/Creator: Ryder, Robert T. Publication/Creation: [Washington D. C.] : United States G.P.O., 1992 Resource Type: Book Access & Availability: Loading