Series Number Id: UNKNOWN. Sheet number: [parts of 36b(44b) SW, 44c SE, 51c NW, 51d NE]. "3rd Field Survey Co. R.E. (1254)". Third Army rear area between St. Pol and Frevent. Artillery map, specially surveyed by 3rd Field Survey Company RE and printed for Third Army Artillery School. Detail and grid black; contours brown. Shows trig points, two survey pickets, and a Trig Tree SW of Moncheaux., WW1 Trench Map Collection: Box PC18, Envelope 548.