Contour interval 20 feet.;"Surveyed in 1914, 1916 and 1920.";"Surveyed in cooperation with the States of Kentucky and Illinois."; (W 88⁰30ʹ00ʺ--W 88⁰15ʹ00ʺ/N 37⁰30ʹ00ʺ--N 37⁰15ʹ00ʺ);Relief shown by contours and spot heights.;1 map, colored;45 x 36 cm.;1:62,500