A navigational map, “Chart of the Columbia River for 90 miles from its mouth [cartographic material] / drawn from several surveys in the possession of W.A. Slacum ; by M.C. Ewing.” Relief shown by hachures. Depths shown by soundings. Oriented with north to the left. Profiles: Cape Disappointment N.N.E. by compass distance 10 miles -- Cape Disappointment N.N.E. 6 miles. "S. Doc. No. 470. 25 Con. 2d S." Series: Senate document (United States. Congress. Senate) ; 25th Congress, 2d session, no. 470. Imaged map dissected and mounted on cloth backing. Item has also been identified as bb017535.

A map of the mouth of the Columbia River, Oregon Territory as surveyed by the United States Exploring Expedition in 1841 under commander Charles Wilkes. Relief shown by hachures. Depths shown by soundings. Inset details soundings of the Bar of Columbia River. Item has also been identified as bb017536.