Relief shown by hachures. Prime meridians: Washington and London. Facsimile. Historic Maps copy has note taped to verso: One hundred and sixty copies have been made by the American Philosophical Society Library from the original copperplate engraving ... of the map in the "Biddle edition" of History of the Expedition under the command of Captains Lewis and Clark ... Of these 150 numbered copies are now offered to collectors and institutions.
[Philadelphia : American Philosophical Society, 1979]