Series Number Id: GSGS 2742; Sheet number: 57d SE; Edition number: 2a, Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC11; envelope_number: 307, Stamp on reverse: "57th Siege Battery. Royal Garrison Artillery". Manuscript in pencil on face: British battery position north of Albert (SW of Aveluy Wood) & zero line to Pozieres Windmill, & part of another line to La Boisselle; also line to north of Ovillers & Contalmaison & Mametz Wood - British front during Somme battle (July 1916); Manuscript on reverse; office Copy; several stains.