Important moral results had been gained by the Americans, but they were not aware of the fact, and expected the battle to be resumed. At about seven o'clock the next morning, however, as the light mist slowly dissolved, their astonished eyes beheld the Mexican line gliding off into the road; and presently, like the tail of a huge serpent, its rear wound away into the chaparral, and vanished. Taylor gazed and reflected, moved a short distance, waited to ascertain through a party of dragoons that it was a genuine retreat, consulted with some of his principal officers, and then decided on pursuit; but the forenoon had to be spent in erecting breastworks and planting four heavy cannon to defend the train, which he now saw should be left behind; and he merely sent forward a composite force of 220 men, under Captain McCall of the Fourth Infantry, to harass the Mexican rear.[8.15] [Illustration: BATTLE OF RESACA DE LA PALMA] [ARISTA IN A NEW POSITION] Arista turned this delay to good account. The chaparral and woods that his troops had been seen to enter extended with some interruptions to the Rio Grande, a distance of approximately seven miles; and two hours before noon, after marching about halfway through it, he stopped at the Resaca de Guerrero. The Resaca was an ancient channel of the river, but it now consisted merely of a shallow, muddy ravine somewhat in the shape of a bow, several hundred feet wide and three or four feet deep at the banks, lying substantially east and west across the route, with its concave side toward Palo Alto. At the bottom of it, both to the right and to the left of the road, lay narrow ponds, and the space between the water and the banks was rather closely filled with bushes and small trees. Facing round here, Arista planted three or four guns at the right, or east, of the road from Palo Alto where it approached the Resaca, two at least--hidden with branches of trees--on the southern bank of the Resaca, and other pieces at suitable points toward his left. The infantry were placed in two wings divided by the road, with much the greater weight on the right hand, some of the troops taking position just in the rear of the ravine, some behind its northern bank, and some in the chaparral still farther forward. The headquarters tent was pitched in a small clear space or _placeta_ about 500 paces back on the left of the road, and Torrejón's cavalry halted in the same road still farther away; while Canales with two guns, placing himself on the left a considerable distance back from the Resaca, guarded a cross-road leading to Arista's rear.[8.16]