Scale 1:500,000. 1 in. equals approximately 8 miles ; Lambert conformal conic projection based on standard parallels 33° and 45° (W 97°14ʹ21ʺ--W 89°29ʹ00ʺ/N 49°23ʹ04ʺ--N 43°29ʹ57ʺ)..
Note:
Relief shown by spot heights. "Base map drainage modified in 1974." Base map "Compiled in 1963. Edition of 1965." Includes text and table of hydrologic units.