At dawn of the 16th they started again, and winding along the left bank of the river for about a league, and then ascending the heights which shut it in, marched through a mountainous country, the rugged hills clothed with wood to their summits, and passing the villages of Encinillas and Bisquesas, and crossing the river Nela, encamped a little beyond Medina de Pomar, on the Trueba river. On the 17th their march was through mountain tracks impassable for artillery. They were in fact striking across the country to the great road from Burgos to Vittoria, in order to intercept the enemy who were proceeding by that road; and after a fatiguing march encamped in a woody height near the river Loza. Picquets were thrown out, as the enemy was supposed to be not far distant, and the Regiment was placed in thick wood, where there was hardly room to pitch the tents. On the 18th they moved very early. A troop of German hussars led, and then came the 1st Battalion, one company being in advance. After marching about two leagues they arrived at the point where the road by which they were moving struck into the great road, which by a steep descent between high banks, enters the village of San Millan. Here they came upon a strong rear-guard of the enemy who were coming down the hill towards San Millan. The German cavalry first attacked a force of cavalry which was with the rear-guard, and which made a stand; but they soon routed them, and brought in many prisoners. Then Barnard extending the 1st Battalion came down upon the infantry, through the wooded height which overhung the road, and with a sharp and destructive fire put them into confusion. The 3rd Battalion also became actively engaged; and the enemy being broken, retired rapidly, through San Millan and up the hill beyond it, closely pursued by our people. When the Riflemen were beginning the attack Lord Wellington rode up, and directed their movements. As he had another division ready to intercept the French, at Espejo, some distance in advance towards Vittoria, he desired Quartermaster Surtees to go and fetch a peasant who was supposed to be with the 1st Battalion, to guide him to Espejo. But the guide not liking the fire, was nowhere to be found; and on Surtees reporting this to him, Lord Wellington galloped off towards Espejo, without a guide. The Riflemen continued the pursuit of the enemy; who on getting on the height above San Millan, again showed front, and formed up some battalions. But the inexorable Riflemen again pressed them so hard, that they fled through Villa Nueva and Villa Naña; and the country being admirably suited for Riflemen, they inflicted on them great loss.