1908. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1906.";"Surveyed in cooperation with the State of Illinois.;Relief indicated by contours and spot heights.;1... Geological Survey (U.S.) and Geological Survey Division (Urbana, Ill.).
Search Results
1908. Geological Survey (U.S.). Contour interval 10 feet.;"Surveyed in 1906.";"Surveyed in cooperation with the State of Illinois.";Relief indicated by contours and spot heights.;... Geological Survey (U.S.) and Geological Survey Division (Urbana, Ill.).
1908. Geological Survey (U.S.). Contour interval 10 feet.;"Surveyed in 1906.";"Surveyed in cooperation with the State of Illinois.";Relief indicated by contours and spot heights.;... Geological Survey (U.S.) and Geological Survey Division (Urbana, Ill.).
1908. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1890.";Relief shown by contours.;1 map, colored;45 x 34 cm.;1:62,500. Geological Survey (U.S.).