Series Number Id: GSGS 3439. Sheet number: part of sheet 51. Battle of Arras preparation; trench, target and hostile battery map. "3rd Field Survey Co. (1405)". "Ordnance Survey, February, 1917." Grey base map; German trenches and names red; British trenches to depth of 300 yards blue. Overprint in dark blue-purple: "Artillery" [target and hostile battery reference], with artillery details. Overprint in green: [Enemy Organisation] Reference, showing railways, roads and tracks chiefly used, and more., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC21; envelope_number: 670.