First Army situation map, mid-day Aug. 27th 
Series Number Id: UNKNOWN. Sheet number: parts of sheets 36 and 57. [First Army Front], First Army situation map, 27 August . Title in red overprint. "[1st] Field Survey Battn. R.E. 6788 [numbers crossed out with red overprint and followed with] 6794". Grey gridded base map (enlarged 1:40,000). British Line west of Lens and Bapaume and east of Arras shown in red for 20th, 26th, 27th August. Scale of miles and kilometres in right margin of base map., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC16; envelope_number: 461.