Series Number Id: UNKNOWN. Sheet number: Part of Sheet 36. Hill 70, Canadian attack 1917; trench situation and enemy distribution map. "Trenches corrected to 11-8-17." "1st Field Survey Co., R.E. 2605 [numbers crossed out and replaced with blue overprint] 2619". Detail, grid and contours grey; German trenches red. Blue overprint shows "probable distribution of German Forces noon 15'8'17"; approximate British Line shown with solid blue line; and approximate British Posts shown with blue circles., Includes collector's stamp. Used by Major J.C. Thomson MC, OC 20th Siege Battery RGA (8-inch hows). WW1 Trench Map Collection: Box PC15, Envelope 415.