AMS revision. United States. Army Map Service. Great Britain. War Office. General Staff. Geographical Section. Series G.S.G.S. 3789. In upper margin: Eastern China 1:50,000. Relief shown by spot heights.Depth shown by contour interval at 20 feet. One thousand yard world polyconic grid. Three types of internal boundaries, three classes of railroads, with some distances in kilometers, three classes of roads or tracks, woods and marsh type vegetation, and telegraph lines are shown. British grid deleted and world polyconic grid added by AMS, 1944.