Oil and Gas Fields Map of Ohio, Map PG-1, by R. R. Riley, M. T. Baranoski, and L. H. Wickstrom, 2004. 51- x 41-inch format, 1:500,000-scale map (1 inch equals about 8 miles), full color. All of the state's known areas of oil and gas production since the 1860s are featured on Map PG-1, color-coded based on the producing geologic formation. A large table provides information on the discovery well for each field. Information on how the map was prepared is provided in an explanatory text. An interavtive version of this map is available online at www.OhioGeology.com.