| 1. |  | Sibley quadrangle, Illinois : 15 minute series (topographic) | Sibley (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 1940. Topography by plane-table methods 1947"; "Contour interval 10 feet."... |
