Series Number Id: UNKNOWN. Sheet number: 11 and 12. Air intelligence map, Battle of Cambrai, 1917. Overprint on composite of two small sheets (pinned together) of grey squared base. Title in blue overprint. "[3rd] Field Survey Coy., (10021)". "B.I. XIIIth Wing 6 PM 23.11.17" in blue overprint. "Original British Front Line 19-11-17" shown and also the Cambrai Salient Line, including Bourlon and Bourlon Wood, as at 6 p.m. 23-11-17. Manuscript on verso in pencil: Cambrai Nov 1917., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC19; envelope_number: 592.