Reconnaissance map of the Lower Kuskokwim region, Alaska / U.S. Geological Survey ; Alfred H. Brooks, Geologist in charge of division, topography by A.G. Maddren, R.H. Sargent and W.S. Post.Geological Survey (U.S.)1921"Surveyed in 1898, 1914,1915,1916, and 1919."Key map of surveyors' areas of responsiblity in margin.Relief shown by contours, land forms and spot heights.cartographic