United States. Geological Survey. U.S.G.S. Relief shown by 20 feet contour interval and spot heights. Surveyed in 1886-7. Triangulation by the U.S. Coast and Geodetic and Borden Surveys. In upper left margin: U.S. Geological Survey, J. W. (John Wesley) Powell Director. Verso: Description of the topographic map of the United States.
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