The heavy guns of the Allies continued to shell the Somme bridges in the Chaulnes region which the Germans would have to cross if they were forced to evacuate this territory. South of the Somme Haig's troops captured the village of Proyart and linked up their positions east of Mericourt with those to the east of Etinehem, which is on the northern bank.
While the Allies' advance had slowed down owing to the increasing number of reserves which the Germans threw into the battle line the enemy was gradually being thrust out of the strongest positions which he had held so long.
Since the beginning of the Allied counteroffensive which began on July 18, 1918, they had captured over 70,000 prisoners, about 1,000 guns and over 10,000 machine guns.
On August 12-18, 1918, French forces under General Humbert resumed the offensive between the Matz and Oise Rivers and a drive forward was made into the German lines. East and north of Gury good progress was recorded, increasing the menace to Lassigny two miles to the northeast. The French also advanced two kilometers north of Cambronne, and eastward in the valley of the Oise, owing to continued pressure, the Germans were forced out of their trenches to the west of Bailly.
The Allied artillery had now fall control of the converging roads in and out of Noyon, near the southern end of the line, notably that running northward to Ham. Under these conditions any attempt of the enemy to carry out a retrograde movement was greatly hampered.
August 13-14, 1918, the Germans began the evacuation of a five-mile front north of Albert, extending from Beaumont-Hamel northward through the villages of Serre and Puisieux-au-Mont to Bucquoy. On the French front the town of Ribécourt, six miles from Noyon and on the road to that city, was wrested from the Germans as the result of a further thrust between the Matz and Oise Rivers.
General Humbert's advance had made the French position on the southern part of the Thiescourt plateau secure. The Germans now occupied Plemont, which they captured early in the June fighting, and reoccupied their old trenches, which were still organized with wire entanglements. Here as elsewhere the Germans had the advantage that they were falling back on their supplies while the French were forced to bring theirs up through a very difficult country. General Humbert and his men had been fighting now continuously for four days, a great part of the time in gas-drenched sectors and against strongly held positions which the Germans had deemed impregnable. The French now held possession of two important crests, Claude Farm and Ecouvillon, and were within a hundred yards of Le Monolithe, another high plateau commanding a wide sweep of territory to the north and east.
All the German positions between the western outskirts of Bray and Etineham were captured by the Australians, giving the British control of the river banks southwest of Bray. The Australians after a hard and brilliant fight drove the enemy from the Cateau Wood.
On the southern end of the Picardy battle line General Humbert's army continued to press the advance toward Noyon. The desperate defense maintained by the Germans on the Chaulnes-Roye road for a time delayed French storming operations which were impending. General Rawlinson's army, which held the line to the north of the French positions, was subjected to fierce German attacks on the whole front. The enemy seemed determined to maintain his hold on the Chaulnes heights regardless of the cost. The French advance was made against a line that was thinly held, but which bristled with machine guns so numerous that there was one to every two men, it was reported. Moreover, the battle area traversed by the French troops was deluged with mustard gas, so that there were days in which they were forced to wear their masks even when snatching a few hours of repose. Yet the French continued to win dominating positions and forced the Germans back in spite of all attempts to hinder their progress.
On August 15, 1918, Australian troops under Marshal Haig made a drive against the German defenses on the center of the Somme battle front between Chaulnes and Roye and captured the villages of Parvillers and Demery. Progress was also made south of the Somme, southeast of Proyart, and to the northwest of Chaulnes. North of Albert, in the sector where the Germans were forced to evacuate their positions which projected into the British line between Beaumont-Hamel and Bucquoy, Haig's troops continued to push forward. On General Humbert's front east of Montdidier his tireless fighters conquered two strongly fortified farms to the northwest of Ribécourt.