Contour interval 20 feet.;"Surveyed in 1915-1916.";"Surveyed in cooperation with the States of Illinois and Missouri."; (W 89⁰45ʹ00ʺ--W 89⁰30ʹ00ʺ/N 38⁰00ʹ00ʺ--N 37⁰45ʹ00ʺ);Relief shown by contours and spot heights.;1 map, colored;45 x 36 cm.;1:62,500