The light division had been directed to head the French at San Estevan or Sumbilla. The order was received on the evening of the 31st, and General Alten, threading the defiles of Zubieta and descending the deep valley of Lerins, reached Elgoriaga about mid-day on the 1st of August, having then marched twenty-four miles. He was little more than a league from Estevan, was about the same distance from Sumbilla, and the movement of the French along the Bidassoa was immediately discovered. Instead of moving direct on Sumbilla he turned to his left, clambered up the great mountain of Santa Cruz and made for the bridge of Yanzi. The weather was very sultry, the mountain steep and hard to overcome, many men fell and died convulsed and frothing at the mouth, others whose spirit and strength had never before been quelled, leaned on their muskets and muttered in sullen tones that they yielded for the first time. However, towards evening, after marching nineteen consecutive hours, and over forty miles of mountain roads, the head of the exhausted column reached the edge of a precipice near the bridge of Yanzi. Below it, within pistol-shot, Reille’s divisions were seen hurrying forward along the horrid defile in which they were pent up, a fire of musketry commenced, and the scene which followed is thus described by an eye-witness.[37] “We overlooked the enemy at stone’s throw, and from the summit of a tremendous precipice. The river separated us, but the French were wedged in a narrow road with inaccessible rocks on one side and the river on the other. Confusion impossible to describe followed, the wounded were thrown down in the rush and trampled upon, the cavalry drew their swords and endeavoured to charge up the pass of Echallar, but the infantry beat them back, and several, horses and all, were precipitated into the river; some fired vertically at us, the wounded called out for quarter, while others pointed to them, supported as they were on branches of trees, on which were suspended great coats clotted with gore, and blood-stained sheets taken from different habitations to aid the sufferers.” On these miserable supplicants brave men could not fire, and so piteous was the spectacle that it was with averted or doubtful aim they shot at the others, although the latter rapidly plied their muskets in passing, and some in their veteran hardihood even dashed across the bridge of Yanzi to make a counter-attack. It was a soldier-like but vain effort, the night found the British in possession of the bridge; and though the great body of the enemy escaped by the mountain path to Echallar, the baggage was cut off and with many prisoners fell into the hands of the light troops which were still hanging on the rear in pursuit from San Estevan.