Series Number Id: UNKNOWN. Sheet number: parts of 57c N.W. N.E., S.W. & S.E. Edition number: 5f. Battle of Cambrai. "Secret, objective and barrage map." "Special sheet". "Detail and trenches revised to 1-11-17." "Field Survey Co (10,158)". "Approximate British front line 1-11-17." Detail and grid grey; contours yellow-ochre; trenches in red; approximate British front line in black. "517" printed in cartouche. Barrage lines and details for Cambrai battle, including smoke barrages, printed in green, brown and black., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC27; envelope_number: 782.