Valencia's instructions were to block the way from Coyoacán to Tacubaya with men and works; but he mounted at once, rode on south by the turnpike, passed Ansaldo--a farmhouse buried in its orchard, two miles and a half or so from San Angel--and a strong half-mile beyond it paused. On his right, open ground sloped gradually back into a rounded hill, some three or four hundred yards from the road; and below him on the left flowed a small but lively stream at the bottom of a deep, wide ravine, near the opposite side of which stood the adobe buildings of Padierna farm.[26.4] From this point a mule-path, barely practicable for horses, wriggled off in the direction of San Agustín, here about four miles distant in a straight line; and--covering the whole intermediate plain from San Antonio and San Agustín on the one side to Padierna and San Angel on the other, from Coyoacán on the north to the mountains on the south--extended a _pedregal_ or lava bed, which looked as if a raging sea of molten rock had instantly congealed, had then been filled by the storms of centuries with fissures, caves, jagged points and lurking pitfalls, and finally had been decorated with occasional stunted trees and clumps of bushes. After pursuing the mule-path for some distance, ordering a camp and batteries established on the slope of the rounded hill, and instructing experts to reconnoitre the ground thoroughly, Valencia returned to his post; and in the evening, on learning from the experts that four other paths--one of them available for artillery--led from San Agustín to San Angel, he summarized the reconnaissances in a letter to Santa Anna, complaining that he had neither room to manoeuvre nor time to fortify where he was, asking leave to change his position, and calling for 2000 more men.[26.4] The next day, Wednesday, the eighteenth, Santa Anna, writing back that Scott intended to attack San Antonio, ordered Valencia to place his troops at Coyoacán, and send his artillery to Churubusco, a mile farther east. Valencia, who by this time had placed a strong outpost on the mule-path and sappers on the rounded hill, replied that Scott, striking both at San Antonio and at San Angel, would push his thrust in whichever direction he should find the easier, and that he could not conscientiously leave the second point unguarded by obeying those orders. Notes worthy of the most finished and effusive pirates were then exchanged; and in the end Santa Anna, who longed to remove his insubordinate general but dared not, authorized him to do as he pleased and assume, of course, the attendant responsibility.[26.3] Accordingly on Thursday morning Valencia advanced with trumpets, drums and flags to the rounded hill, and proceeded to array his forces. A long, low, earthen parapet with an angle at the southern end already faced Padierna, and five guns were in battery; but the summit of the hill was neglected.[26.4] [SCOTT FEELS HIS WAY]