The marsh area at La Fère is about a mile and a half wide, so that the frontage which needed active defence by each Brigade was roughly four miles. On so vast a frontage a defence by continuous trench lines was clearly out of the question, and the British defence was designed to be in great depth. It was divided into three zones of defence. The Forward Zone, about 1000 yards in depth, relied for its defence on small company redoubts with the space between taken up by hidden machine-guns. This zone was intended to act as a "shock-absorber" in which the first intensity of the enemy's onslaught might be met and checked. The main defence was to be offered in the Battle Zone, about 1500 yards in rear of the Forward Zone. The Battle Zone occupied a depth of about 2000 yards and was to consist of isolated and wired forts, again strengthened by inter-supporting machine-guns. It was hoped that a final check might be administered to the enemy's attempts in this zone, but in rear of it a further defensive system, in this case a continuous line, was to be created as a Rear Zone. Beyond this again the Somme line was to be put into a state of defence. At the date of taking over this area from the French the defensive organisation on the lines above indicated was practically non-existent. Very little depth was provided for in the defence and in rear of the Forward Zone practically all was yet to be done. The Battle Zone redoubts were inadequate and insufficiently wired, while the Rear Zone line was merely spit-locked. For weeks, therefore, the whole energies of every available formation, infantry holding the line, engineers, pioneers and labour corps units from all parts of the world, were concentrated on the enormous task of converting the G.H.Q. scheme into a reality. Valuable time which could have been well spent in training the infantry in defensive measures and counter-attack, and in assimilating the new personnel which had been brought into battalions by the reorganisation of January, was inevitably devoted to entrenching and wiring work, wearying in itself and trying as only work done against time can become. All ranks, however, were sufficiently impressed by the need, and all were working with the zeal born of a grim determination to prove themselves equal to the demands which would be made upon them.