| 3. |  | Illinois-Iowa-Missouri, Keokuk quadrangle | Illinois; Maps; Topographic maps; Topography; Keokuk; Missouri | 1 map : col.; Relief shown by contours and spot heights.; "Culture and drainage in part compiled from aerial photographs taken by Air Corps, U.S. Army"; "Surveyed in 1921, 1928 and 1932"; "Contour intervals... |