| 1. |  | Sailor Springs quadrangle, Illinois : 15 minute series (topographic) | Sailor Springs (Ill.); Maps; Topographic maps; Topography; Illinois | 1 map : col.; Relief shown by contours and spot heights.; "Culture and drainage in part compiled from aerial photographs taken 1952. Topography by plane-table surveys 1953."; "Contour interval 10 feet."... |
