Hydrologic unit map--1974, State of Arkansas.
Scale 1:500,000; 1 in. equals approx. 8 miles. Relief shown by spot heights. "Lambert conformal conic projection based on standard parallels 33⁰ and 45⁰." "Base map drainage modified 1974." Includes text and indexed table of hydrologic units. Available also through the Library of Congress Web site as a raster image. AACR2
Water Resources Council (U.S.) - Geological Survey (U.S.)
State of Arkansas : 1990
Relief shown by contours and spot heights. At head of title: Department of the Interior, United States Geological Survey. Alternate title in lower right margin: Arkansas. UTM grid: Zones 15 and 16. "Compiled in 1989 from USGS 1:100 000-scale topographic maps dated 1975-1986." Includes population key. "34092-E1-ST-500." Available also through the Library of Congress Web site as a raster image.