Map of Lockhart River Basin, Great Slave Lake District, Northwest Territories : including the head waters of Thelon, Back and Coppermine Rivers / compiled, drawn and printed at the Topographical Survey of Canada.Canada. Topographical Survey1925At head of title: "Department of the Interior."Includes notes, source of information and 2 inset maps.Map of Lockhart River Basin, Great Slave Lake District, Northwest Territories -- Great Slave Lake District -- Pike's Portage route, great Slave Lake tocartographic