Notes: | Relief shown on some maps by contours and spot heights. Depths shown on some maps by soundings. Includes maps and diagrams of Chicago-area waterways, railroads, the tracks of the Illinois Tunnel Company, and planned harbor improvements. Also includes nautical charts of Chicago Harbor, the North and South Branches of the Chicago River, the Grand Calumet River, the Little Calumet River, Calumet Harbor, and the Indiana Harbor Canal. Nautical charts show building footprints of nearby structures. "Engraved and printed by the U.S. Geological Survey." "To accompany report of this date [Oct. 7, 1911] to the Chief of Engineers, U.S. Army." "House Doc. 237; 63d Cong., 1st Sess."
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