| 1. |  | Mason City quadrangle, Illinois : 15 minute series (topographic) | Mason City (Ill.); Illinois; Maps; Topographic maps; Topography | 1 map : col.; Relief shown by contours and spot heights.; "Culture and drainage in part compiled from aerial photographs taken 1939-1940. Topography by plane-table methods 1947-1948."; Shows roadway classification... |
