Neither Reille nor the few prisoners he had made could account for more than six Anglo-Portuguese divisions at these defiles; hence, as no enemy had been felt on the great road from Burgos, the king judged that Hill was marching with the others by Valmaceda into Guipuscoa, to menace the great communication with France. It was however clear that six divisions were on the right and rear of the French position, and no time was to be lost; wherefore Gazan and D’Erlon marched in the night to unite behind the Zadora river, up the left bank of which they had to file into the basin of Vittoria. But their way was through the pass of Puebla de Arganzan, two miles long, and so narrow as scarcely to furnish room for the great road: wherefore to cover the movement, Reille fell back during the night to Subijana Morillas on the Bayas river. His orders were to dispute the ground vigorously, for by that route Wellington could enter the basin before the others could thread the pass of Puebla; or he might send a corps from Frias, to attack the king on the Miranda side in rear while his front was engaged in the defile. One of these things the English general should have endeavoured to accomplish, but the troops had made long marches on the 18th, and it was dark before the fourth division reached Espejo: D’Erlon and Gazan, therefore, without difficulty passed the defile, and the head of their column appeared on the other side just as the allies drove Reille back from the Bayas. Wellington had reached that river before mid-day the 19th, and, if he could have forced it at once, the other two armies, then in the defile, would have been cut off; Reille was however well posted, his front covered by the stream, his right by the village of Subijana de Morillas, which was occupied as a bridge-head; his left was secured by rugged heights, and it was only by a combat in which eighty French fell that he was forced beyond the Zadora; but the other armies had then passed the defile, the crisis was over, and the allies pitched their tents on the Bayas. The king now heard of Clausel at Logroño, and called him to Vittoria; he also directed Foy, then in march for Bilbao, to rally the garrisons of Biscay and Guipuscoa and join him on the Zadora. These orders were received too late.