Topographic sheets. Indian Territory-Oklahoma, Stonewall quadrangle, lat. 34° 30′-35°, long. 96° 30′-97°. Scale 1:125,000, contour interval 50 ft. owa-Illinois, Peosta quadrangle, lat. 42°-42° 30′, long. 90° 30′-91°. Scale 1:125,000, contour interval 20 ft. Edition of Apr. 1901.