Though the duties of the H.A. Signal Officer were somewhat reduced by the appointment, in January, of a R.E. Signal Officer to each H.A. Group, the commencement by the enemy of systematic counter battery work, in imitation of the British methods initiated in the previous year, made it more than ever difficult to keep the forward lines in continuous operation. A scheme for the forward extension of the buried system, till recently used by the French, was prepared under the greatest transport difficulties, the drums having to be man-handled about half a mile across country by night, and a portion of the material was got up to Marrières Wood, next year the scene of the South African Brigade’s fine stand in the March retreat. But the deep crust of frozen ground prevented digging, and the important local attack of the 8th Division on the 4th March on Fritz Trench above Bouchavesnes had to be carried through without the assistance of the new buried communication, and as most of the above-ground cables were cut, the first news of the assaulting troops was brought by pigeon to the Corps Loft at Etinehem. The attack was fully successful, and the effective use made by the artillery of the excellent observation secured by it, no doubt expedited the general retirement of the enemy in this sector. A few days later symptoms of this retreat became obvious in the shape of villages burning and large transport movements in the enemy back area. The general withdrawal began on the 15th March, the enemy falling back on the Corps front across the Canal du Nord. As the Fourth Army was not destined to play a part in the spring offensive, it had been heavily depleted both to swell the concentration northwards in preparation for the coming Arras battle, and to take over additional ground from the French, the sector on the XV. Corps right south of the Somme having been occupied by the III. Corps during February. Apart, therefore, from the tremendous transport difficulties due to continuous wet weather succeeding the frost, and the methodical destruction of bridges, roads, and railways, there was not sufficient strength to press the enemy closely, but the advance was conducted methodically, touch with the enemy rearguards on the Corps front being maintained by the Wiltshire Yeomanry and the Corps Cyclist Battalion until a Cavalry Division could come up.