The moment had now come for the assault. Under cover of a final artillery preparation the bluejackets, marines, and North Lancashire men began to climb the boulders which covered the front face of the kopjes. A third of the way up a momentary halt again became necessary, as the British shells were bursting just in front of the assaulting line. Then the Royal artillery ceased fire and the assailants, having been joined by their Brigadier, Lieut.-Col. Money, and the supporting Northamptonshire and Yorkshire companies, eagerly dashed on up to the crest. The eastern face of the position was carried at the same time. The enemy had no desire to await this final onslaught and had already retired to the broken ground further to the north. If the times were correctly recorded, the advance and capture of this kopje did not take more than half an hour, the final assault having been delivered at 9.30 a.m. [Sidenote: The Boers retreat.] The commando on the Boer right had had but little share in this fight, being held in check by the force on the British left detailed expressly for that purpose. The loss of the razor-backed kopje rendered the whole position untenable; De la Rey and Prinsloo therefore fell back with their men northwards, pursued by long-range volleys from the British infantry. As soon as he was informed that the infantry had made good the crest line, Lieut.-Col. Hall, commanding the Royal artillery, pushed on with both the field batteries to the ridge between the central and eastern kopjes, but the enemy had by this time retreated too far for the fire of the British guns to be effective. The batteries then were taken to water, of which the animals were in dire need. [Sidenote: The attempt to cut off the fugitives.] Meantime the two bodies of mounted troops, which, according to Lord Methuen's scheme, were to seize ground in the path of the now retreating Boers, had set out on their mission. [Sidenote: The western march.]