On April 4th, a violent German effort on the left bank of the Avre, against the 36th Corps, was twice checked, but the enemy finally succeeded, at very heavy cost, in capturing Mailly-Raineval, Arrière-Cour Wood, Morisel and Castel. On April 5, under the command of General Robillot, the French counter-attacked: the 127th, 166th and 59th divisions towards Mailly-Raineval, and the 17th division in the direction of Moreuil. After driving the enemy from Arrière-Cour Wood, they returned to the outskirts of Mailly-Raineval. In front of Sauvillers, where the tanks did good work, they advanced along the plateau. To the west of Castel, in Sénecat Wood, a furious engagement took place, in the course of which the enemy were driven back with a loss of 100 prisoners. On April 17, the French attacked from Mailly to Castel, captured the greater part of Sénecat Wood, gained a footing in Gros Hêtre Wood, reached the outskirts of Castel--bristling with machine-guns--and on the south attained the heights which dominate the Avre, after taking over 650 prisoners, including 20 officers. The same day, a single French battalion thrown against the village of Castel--held by five companies of infantry and two companies of machine-gunners, of the German 389th regiment of shock troops--advanced 1,400 yards, capturing several redoubts, 254 prisoners (including 10 officers), and 31 machine-guns. On this day also, the tanks played a great part in the capture of Sénecat Wood. The commanding officer of a company of tanks personally took over one of the machines, the crew of which had been put out of action. Making straight for Castel, he swept the streets of the village with his machine-gun, then returned safely to the French lines. Another tank, in hot pursuit of a retreating German battery of 77's, penetrated over 600 yards into the enemy's lines, where it broke down. The gallant crew thereupon got out their machine guns and held off the enemy until their ammunition ran out. On April 24, an enemy attack on Sénecat Wood failed. On May 11, during a violent attack, the Germans temporarily gained a footing in the woods to the south-west of Mailly, but counter-attacks drove them out. On July 12, the French attacked near Castel and to the south-east of Rouvrel, capturing Castel and 500 prisoners. On the 23rd they took Mailly, Sauvillers, and Aubvillers, capturing 1,800 men, 54 officers, four 77's, 45 minenwerfer, and 300 machine-guns. On August 8, Debeney's offensive cleared Morisel, and the 66th Division captured Moreuil. [Illustration] _Return to and keep along the road._ Trenches, saps and battery positions are met with. _After crossing the Louvrechy-Thory road, the Ailly-sur-Noye-Montdidier road is reached. At the crossing, and before taking_ G.C. 26, _on the left, to Grivesnes, tourists interested in archæology should take it on the right to visit the church of_ =Ailly-sur-Noye= _(5½ kms.) Otherwise, keep straight on to_ =Folleville= _(4½ kms.) (See sketch-map, p. 79.)_