Parts of Sheets 57d.SE, 57c.SW, 62d.NE, and 62c.NW. Series: GSGS 3188. Trenches corrected to 2-6-16, Ordnance Survey 1916. Showing the situation before the opening of the Battle of the Somme. The intention was that this map would be printed at 1:10,000 scale, but owing to a mix-up in instructions it was reproduced at 1:20,000. Nevertheless, it proved very popular [source: Lt. Col. M. N. MacLeod, History of 4th FSC/B]. Annotations: old and new boundaries between divisions, including French XX Corps. Blue pencilled dots, and brown solid and dashed lines. Location: Research Collections, Fonds: WWI Trench Maps France, Box 25, Envelope 749.