Ernest Oberholtzer is educating the reader about the impact of proposed dams. This could be the Backus-proposed dams in the mid-1920s. Dotted lines, ink on parchment, define the Rainy Lake Watershed and the international border. Rail lines are drawn and major lakes are noted. This could well be Oberholtzer's hand-work. Map goes from the western shore of Lake of the Woods to Fort William on the east. Rainer [sic] town name is spelled wrong.