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.