Series Number Id: GSGS 3547. Battle of Messines. [Composite, cut down] Second Army Front, map J, Ordnance Survey April 1917, and another map to the east (unidentified, possibly GSGS 3548). Detail and grid grey; water blue; German trenches red, with names in blue., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC17; envelope_number: 523, Manuscript on face: British field artillery creeping barrage lines and details eastwards through Oosttaverne from dotted black line. For 19th Div. sector near Wytschaete: 19th Divl Arty Group - A, B, C & D Sub Groups. Manuscript on reverse: Secret Map AX6.