By March 25 they had covered an area of about 500 square miles and had penetrated beyond Croisilles, Bapaume, Péronne, Brie, Nesle, and the forest northeast of Noyon. In the two following days they recovered the entire battlefield of the Somme, occupied the British railway junction and supply depot at Albert, drove the British four miles down the Somme, and took Roye and Noyon from the French, driving the latter across the Oise. On the 29th the French counterattacked and recovered eight square miles between Lassigny and Noyon, but west of this position the enemy, on a twelve-mile front with a penetration of seven miles, enveloped Montdidier. The next day the Germans gained some ground north of the Scarpe before Vimy Ridge and obliterated an ally salient with its vertex at Vrely by straightening their line between the Somme and Montdidier.
From March 29 until April 8 the enemy consolidated his positions on a front which had been expanded from seventy-five miles, including two large salients, to 125 miles, including innumerable small ones, embracing a terrain of about 800 square miles west of the front as it was on March 20.
On April 3 the enemy was strongly counterattacked by the British at Ayette and by the French at Plémont, near Lassigny. Similar counterattacks recovered Hébuterne for the British and Cantigny for the French on April 5; Beaumont Hamel and a strong position west of Albert for the British and a flanking position north of Aubvillers for the French on April 7.
Meanwhile, April 4, the Germans had occupied Hamel and two villages near Grivesnes, driving out the French, and had made a furious assault upon the positions of the latter between the Luce rivulet and the Avre River, but without success. On the 5th they had made similar attacks at five points: they were successful against the British at Dernancourt, against the French at Casel; they were driven back with heavy losses by the British at Moyenneville and Villers-Bertonneux and by the French at Cantigny. On the 6th the enemy had made concentrated attacks at six points: south of Albert, beyond the Vaire Wood, between Hailles and Rouvrel, and on the Oise east of Chauny he gained ground, but his attempt to take Mesnil beyond Montdidier and Mount Rénaud beyond Noyon were costly failures. On the 7th he attacked the British strategic position at Eucquoy and the French position east of Chauny. At the former place he was repulsed with heavy loss; at the latter his official chronicler asserted that he gained ground.
ON THE LILLE FRONT
Then north of the great salient just occupied, the Germans struck, on April 9, between the important British depots of Arras and Ypres, forty miles apart, concentrating on a twelve-mile front between Givenchy and Fleurbaix. During the two following days the concentration moved north five miles, penetrating between Armentières and Messines. On the 11th it had developed as far north as Hollebeke, four miles southeast of Ypres, had partly enveloped Messines Ridge and entirely Armentières and the town of Estaires on the Lys River. By the 12th it had swelled beyond Merville and Lestrem in the south, was threatening the railway junction of Bailleul in the middle ground, had gained a footing on Messines Ridge, and was investing the neighboring heights of Neuve Eglise and Kemmel in the north. By the morning of the 17th the German penetration had reached Locon in the south, the Nieppe Forest in the middle ground, and had occupied Bailleul and the eastern heights of the ridge in the north and threatened the western and more elevated heights of Mont Rouge and Mont Kemmel. Thus in eight days the Germans had developed a sector on the Lille front of originally twenty-two miles, a salient embracing an area of about 825 square miles with a new front of about thirty-five miles.
SUMMARY OF THE FIGHTING
The initial bombardment which preceded the first infantry advance against the Cambrai salient, at 8 o'clock on the morning of March 21, was widely distributed—as far north as Ypres and as far south as the Oise. It consisted mainly of gas and high explosive shells. The first infantry attack, which penetrated the first and second lines on a sixteen-mile front extending from Lagnicourt to Gauche Wood just south of Gouseaucourt, caused a retreat from the salient which had been left exposed to any superior attack since last December. In rapid succession the British positions, now indefinitely exposed on the north, were then attacked between Arras and La Fère, with tremendous concentration between the latter and St. Quentin. According to the German report of the 22d: "After powerful fire by our artillery and mine throwers our infantry stormed in broad sectors and everywhere captured the first enemy line."
From the 22d until the 25th the Germans kept up a heavy fire upon the French front, mingled with raids, both land and air, evidently with the intention of preventing a movement of the French behind the lines as long as the German intentions remained uncertain.