Illinois, Dixon quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1916.";"Surveyed in cooperation with the State of Illinois.";Relief shown by contours and spot heights.;1 ma...
Illinois, Good Hope quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1916.";"Surveyed in cooperation with the State of Illinois.";Relief shown by contours and spot heights.;1 ma...
Illinois, Kings quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1917.";"Surveyed in cooperation with the War Department and the State of Illinois.";Relief shown by contours...
Illinois, Kirkland quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1917.";"Surveyed in cooperation with the War Department and the State of Illinois.";Relief shown by contours...
Illinois, La Harpe quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1916.";"Surveyed in cooperation with the State of Illinois.";Relief shown by contours and spot heights.;1 ma...
Illinois, Morris quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1915.";"Surveyed in cooperation with the State of Illinois.";Relief shown by contours and spot heights.;1 ma...
Illinois, Wilmington quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1916.";"Surveyed in cooperation with the State of Illinois.";Relief shown by contours and spot heights.;1 ma...
Illinois-Missouri, Campbell Hill quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1915-1916.";"Surveyed in cooperation with the States of Illinois and Missouri."; (W 89⁰45ʹ00ʺ--W 89⁰30ʹ00ʺ/N...
Illinois-Wisconsin, Belvidere quadrangle : topography
1918. Geological Survey (U.S.). Surveyed in 1917.;Surveyed in cooperation with the War Department and the State of Illinois.";Relief shown by contours and spot heights.;1 map, col...
Illinois-Wisconsin (Winnebago County), Rockford quadrangle : topography
1918. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1917.";"Surveyed in cooperation with the War Department and the State of Illinois.";Relief shown by contours...
