Trench Map 57d SE

[Terry Carter]

I got a Trench map from Ebay and its 1/20000 57d SE Mailley-Maillet- Auchonvillers-Albert- Beaumont Hamel-Pozieres etc etc. The trenches are corrrected to 17 July 1918. British trenches in Red and German trenches in Blue.

My question is.. when this revision was printed on 17 July, 1918, the front line was still over towards Amiens and the 2nd Battles of the Somme did not commence until 21 August 1918. So..are these old trenches from 1916 that are on the map?

Terry