"The Pittsburg coal bed : an address..."; "White, I. C. (Israel Charles), 1848-1927."; "Coal--Pennsylvania.", "Geology--Pennsylvania."; "White, I. C. (Israel Charles), 1848-1927."; "1897"; "Journal article reprint from: The Proceedings of the American Association for the Advancement of Science, v.46 (1897). "; ""; "P2968"; "pec"; "Geology--Pennsylvania.", "Coal--Pennsylvania."; "14256"; .