The location of the communication trench with respect to the fire trench and the arrangements of the approaches is shown in detail in Plate 1.
The profile of the ordinary communication trench is shown in Plate 23.
Dugouts
During the artillery bombardment few men are left in the fire trenches. The remainder of the garrison is held under cover a short distance to the rear. This cover is provided by a system of dugouts connected with the fire trench through underground passageways that lead to the communication trench. This arrangement is shown in Plate 1.
A profile of the latest type of dugout is shown in Plate 24.
The solid earth cover is from 12 to 18 feet thick, which gives protection from all but the very largest caliber shells.
Plate 24.—Type of dugout.
Effective resistance is supplied by roofing materials as follows:
1. From shrapnel bullets: 2-inch planks covered with 12 inches of earth.