Series Number Id: UNKNOWN. Sheet number: parts of sheets 36 and 57. First Army front, German order of battle, September 1918. Title in black overprint. "[1st] Field Survey Battn. R.E. 6788 [numbers crossed out with black overprint and followed with] 6880". Grey gridded base map (enlarged 1:40,000). Shows "British Line Aug. 20th" in black overprint. Shows German armies (6th and 17th), group (Corps) and divisions, army and group boundaries. Scale of miles and kilometres in right margin of base map., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC16; envelope_number: 426.