Report on the geological survey of the State of Iowa, to the Thirteenth General Assembly, January, 1870, containing results of examinations and observations made within the years 1866, 1867, 1868, and 1869
Iowa Geological Survey; White, Charles A. (Charles Abiathar), 1826-1910; Parvin, Theodore Sutton, 1817-1901; St. John, O. H. (Orestes Hawley); Emery, Rush