The coal fields of the United States. - Bownocker, J. A. (John Adams), 1865-1928.; Campbell, Marius R. (Marius Robinson), 1858-1940. (Washington, U.S. Govt. print. off., 1929)
At head of title: Department of the interior.
Issued also as House doc. no. 1806, 64th Cong., 2d sess.
Keywords: Coal -- Ohio; Coal -- United States