Series Number Id: UNKNOWN. Sheet number: [36 SW]. First Army secret defence map. At head of map in red overprint: Secret. "Showing zones of defence: forward zone [red]; battle zone [blue]; rear zone [green]". "[First] Field Survey Co., R.E. 5741 [numbers crossed out and replace with blue overprint] 5865." Grey squared base map. German front line in red. British front and rear defence lines in red and blue; zones of defence in pink, bale blue and pale green. Includes "Reference" to wire; defended localities (hatched areas); assembly points; posts.
Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC23; envelope_number: 702.