Alaska military expedition : in charge of Captain W.R. Abercrombie, U.S.A. Copper River and adjacent territory / topography by P.G. Lowe, F.C. Schrader, and Emil Mahlo.Geological Survey (U.S.)1898Contour interval approximately 250 feet.Imperfect: Upper portion of map wanting. Dimensions 35 x 50 cm.Relief shown by form lines, hachures, and spot heights.cartographic