THE SOMME BATTLEFIELD.
The battle extended over the Picardy plateau, south and north of the Somme. Before the war, the region was rich and fertile, the chalky ground having a covering of alluvial soil of variable thickness.
The slopes of the undulating hills and the broad table-lands were covered with immense fields of corn, poppies and sugar beet. Here and there were small woods—vestiges of the Arrouaise Forest, which covered the whole country in the Middle-Ages. There were scarcely any isolated houses, but occasionally a windmill, farm or sugar-refinery would break the monotony of the landscape.
The villages were surrounded with orchards, and their low, red-tiled houses were generally grouped around the church. The plateau was crossed by wide, straight roads bordered with fine elms.
The war has robbed the district of its former aspect. The ground, in a state of complete upheaval, is almost levelled in places, while the huge mine-craters give it the appearance of a lunar landscape. The ground was churned up so deeply that the upper covering of soil has almost entirely disappeared and the limestone substratum now laid bare is overrun with rank vegetation. From Thiepval to Albert, Combles and Péronne, and from Chaulnes to Roye, the ground was so completely upturned as to render it useless for agriculture for many years to come, and a scheme to plant this area with pine trees is now being considered.
Nearly all the villages were razed, and now form so many vast heaps of débris. This battlefield is a striking example of the total destructions wrought by the late war.
The Topography of the Ground and the Enemy Defence-works
North of the Somme.—The battle zone, bounded by the rivers Ancre, Somme and Tortille—the latter doubled by the Northern Canal—forms a strongly undulating plateau (altitude 400-520 feet), which descends in a series of hillocks, separated by deep depressions, to the valleys of the rivers (altitude 160 feet). The Albert—Combles-Péronne railway runs along the bottom of one of these depressions.
The higher parts of the plateau form a ridge, one of whose tapering extremities rests on the Thiepval Heights, on the bank of the Ancre. Running west to east, the ridge crosses the Albert-Bapaume road at Pozières, passes Foureaux Wood, then north of Ginchy. It is the watershed which divides the rivers flowing northwards to the Escaut and southwards to the Somme.
The second line of German positions was established on this ridge, while the first line extended along the undulating slopes which descended towards the Allies' positions. There were other enemy positions on the counter-slopes behind the ridge.
These positions took in the villages and small woods of the region, all of which, fortified during the previous two years, bristled with defence-works and machine-guns.
Some of these villages (Courcelette, Martinpuich, Longueval, Guillemont and Combles), hidden away in hollows, were particularly deadly for the Allies; the defenders, unseen, were able to snipe the assailants as they appeared on the hill tops. The Allies had to encircle these centres of resistance before they were able to enter them.
South of the Somme.—The battle zone, bounded by the large circular bend of the Somme at Péronne, formed a kind of arena. The vast, flat table-lands of the Santerre district, separated by small valleys, descend gently towards the large marshy valley of the Somme, in which the canal runs parallel with the river.
Owing to the narrowness of this zone, the Germans were forced to establish their positions close behind one another, and the latter were therefore in danger of being carried in a single rush. On the other hand, the assailants' rapid advance was first hampered, then held by the marshy valley, which prevented them from following up their brilliant initial success.
During the battle, the Germans, driven from their first positions, hastily prepared new ones, and clung desperately to the counter-slopes of the hills which descend to the valleys.
The Different Stages of the Offensive
The offensive of the Somme, the general direction of which was towards Cambrai, aimed at reaching the main northern line of communications, by opening a gap between Bapaume and Péronne.
The main sector of attack—between the Ancre and the Somme—was flanked on either side by diversion sectors north of the Ancre and south of the Somme.
ATTEMPTED BREAK-THROUGH.
A breach was made south of the Somme, but the marshes prevented development, while to the north, the offensive was held on the Ancre lines.
Putting to profit the German failure at Verdun, where the enemy masses, after appalling sacrifice of human life, gradually became blocked in a narrow sector (7½ miles in width), the Allies widened their front of attack.
After an effective "pounding" by the guns which annihilated all obstacles to a considerable depth, the assaulting waves went forward simultaneously along a 24-mile front, feeling for a weak sector where a breach could be made. The attack was a complete success in the diversion sector, south of the Somme, thanks to the nature of the ground, but, as previously stated, it was not possible to follow it up immediately.
North of the Somme the British offensive was held.
Warned by the immense preparations, the Germans were not taken unawares. Their reserves flowed in and resisted on new defensive positions. The advance of the French 6th Army was slowed down to correspond with that of the British.
The Battle of Attrition
(See the sketch-maps on pages [13], [18], [27].)
This attempted break-through (July 1-12) soon changed into a battle of attrition (July 14, 1916, to March, 1917).
The Allies' plan now was gradually to shatter the German resistance by a continuous push along the whole line, and by vigorous action at the various strong-points.
The gains of ground diminished, but the German reserves were gradually used up. In spite of their hastily constructed system of new defences, the Germans realised the precarious nature of their new lines, and were forced, in March, 1917, to fall back and shorten their front.
THE PHASES OF THE BATTLE OF ATTRITION.
NORTH OF THE SOMME.
The Franco-British troops enlarge the conquered positions and attack the centres of resistance: Combles and Thiepval (July 14—September 1).
Combles and Thiepval turned and conquered, after being surrounded (September—November).
The Allies advance toward their main objectives: Bapaume and Péronne (November—March).
SOUTH OF THE SOMME.
The 6th Army (French) held by the Somme Marshes, took up its new position. The 10th Army (French) assembled on its right (August—September).
The 10th Army attacked, but was held in front of Chaulnes (September—October).
The 10th Army (French) failed to encircle Chaulnes, and consolidated its new positions (October—November).
FIELD-MARSHAL HAIG.