The numerous woods and villages in and between these systems of defense had been turned into veritable fortresses. The deep cellars, usually to be found in the villages, and the numerous pits and quarries common to a chalk country were used to provide cover for machine guns and trench mortars. The existing cellars were supplemented by elaborate dugouts, sometimes in two stories, and these were connected up by passages as much as thirty feet below the surface of the ground. The salients in the enemy's lines, from which he could bring enfilade fire across his front, were made into self-contained forts, and often protected by mine fields, while strong redoubts and concrete machine-gun emplacements had been constructed in positions from which he could sweep his own trenches should these be taken. The ground lent itself to good artillery observation on the enemy's part, and he had skillfully arranged for cross-fire by his guns.
A composite system of great strength.
These various systems of defense, with the fortified localities and other supporting points between them, were cunningly sited to afford each other mutual assistance and to admit of the utmost possible development of enfilade and flanking fire by machine guns and artillery. They formed, in short, not merely a series of successive lines, but one composite system of enormous depth and strength.
Many lines prepared in the rear.
Behind this second system of trenches, in addition to woods, villages, and other strong points prepared for defense, the enemy had several other lines already completed; and we had learned from aeroplane reconnoisance that he was hard at work improving and strengthening these and digging fresh ones between them and still further back.
In the area above described, between the Somme and the Ancre, our front-line trenches ran parallel and close to those of the enemy, but below them. We had good direct observation on his front system of trenches and on the various defenses sited on the slopes above us between his first and second systems; but the second system itself, in many places, could not be observed from the ground in our possession, while, except from the air, nothing could be seen of his more distant defenses.
The lines of the Allies.
North of the Ancre, where the opposing trenches ran transversely across the main ridge, the enemy's defenses were equally elaborate and formidable. So far as command of ground was concerned we were here practically on level terms, but, partly as a result of this, our direct observation over the ground held by the enemy was not so good as it was further south. On portions of this front the opposing first-line trenches were more widely separated from each other, while in the valleys to the north were many hidden gun positions from which the enemy could develop flanking fire on our troops as they advanced across the open.
Period of active operations.
The period of active operations dealt with in this dispatch divides itself roughly into three phases. The first phase opened with the attack of July 1, 1916, the success of which evidently came as a surprise to the enemy and caused considerable confusion and disorganization in his ranks.