III. Having made these dispositions, and having left in the camp his two newly-raised legions to serve as a reserve in case of need, Cæsar placed the six others in array of battle, the right resting on the retrenchments. The enemy also drew out his troops and deployed them in face of the Romans. The two armies remained in observation, each waiting till the other passed the marsh of the Miette, as the favourable moment for attack. Meanwhile, as they remained thus stationary, the cavalry were fighting on both sides. After a successful charge, Cæsar, perceiving that the enemies persisted in not entering the marshes, withdrew his legions. The Belgæ immediately left their position to move towards the Aisne, below the point where the Miette entered it. Their object was to cross the river between Gernicourt and Pontavert, where there were fords, with part of their troops, to carry, if they could, the redoubt commanded by the lieutenant Q. Titurius Sabinus, and to cut the bridge, or, at least, to intercept the convoys of provisions, and ravage the country of the Remi, to the south of the Aisne, whence the Romans drew their supplies. The barbarians were already approaching the river, when Sabinus perceived them from the heights of Berry-au-Bac;[249] he immediately gave information to Cæsar, who, with all his cavalry, the light-armed Numidians, the slingers, and the archers, passed the bridge, and, descending the left bank, marched to meet the enemies towards the place threatened. When he arrived there, some of them had already passed the Aisne. An obstinate struggle takes place. Surprised in their passage, the Belgæ, after having experienced considerable loss, advance intrepidly over the corpses to cross the river, but are repulsed by a shower of missiles; those who had reached the left bank are surrounded by the cavalry and massacred.[250] [Sidenote: Retreat of the Belgæ.]