Scale 1:100,000 Relief shown by contours and hachures. Depths shown by soundings. Oriented with north toward upper left. In lower left margin: Andrew B. Graham Co., lithographers, Washington, D.C. In lower right margin: Oliver B. Harden del. "Supplement to the National Geographic magazine, Washington, D.C., October, 1905." "Reprint." Includes notes and profile of canal.