| 1. |  | Amboy quadrangle, Illinois : 15 minute series (topographic) | Illinois; Maps; Topographic maps; Topography; Amboy (Ill.) | 1 map : col.; Relief shown by contours and spot heights.; "Culture and drainage in part compiled from aerial photographs taken 1939 and 1941. Topography by plane-table surveys 1951."; "Contour interval... |
