G.S.G.S. (Canada. Department of National Defence. Geographical Section) ; no. 238. "Revised 1943". Shows 4 classes of roads and railways. Area north of Percy Lake highlighted in yellow. Pencil notes in right margin state, "20 Feb 45 D E D experimental area plotted yellow; Capt Reads experiments cutting ice 743172 and breaking windows 29 Jan to 2 Feb 45; 7 May 45 Mg Aslt Bn, dry gap 74171719, wet gap 74061727". Stamped in black, "H.B. Stuart Collection".