The field of Palo Alto was an open plain, well adapted for the fair fight of a pitched battle, but Resaca de la Palma, which we now approached, possessed altogether different features. The position was naturally strong, and had been judiciously seized by the Mexicans. The matted masses of chapparal, sprinkled in spots with small patches of prairie, formed an almost impassable barrier on both sides of the road along which we were forced to advance. The Resaca de la Palma, or, Ravine of the Palm, fifty yards wide and nearly breast high, crosses the road at right angles, and then bends, at both ends, in the shape of a horse shoe. The low portions of the gully are generally filled with water, forming long and winding ponds through the prairie, whilst, in the rainy season, these pools unite across the ridge which forms the road and flow off towards the Rio Grande. Along the banks of this ravine the thickets of chapparal, nourished by the neighboring water, grow more densely than elsewhere, and, at the period of the battle, formed a solid wall penetrated only by the highway. It was along the edges of this hollow that the Mexicans, led by Arista and Ampudia, had posted themselves in two lines,--one under the front declivity, and the other entrenched behind the copse of chapparal which shielded the bank in the rear. In the centre of each line, on the right and left of the road, a battery was placed, whilst other batteries were disposed so as to assail us in flank. In this strongly fortified position, supported by infantry, cavalry and ordnance, several thousand Mexicans stood around the curving limits of the ravine, ready to rake us with their terrible cross-fires as we advanced by the road between the horns of the crescent.[109] It will be perceived, from this description, that the character of the action was essentially changed from the affair of the 8th. Almost entrenched as were the Mexicans behind the ravine and chapparal, they now stood on the defensive resolutely awaiting our assault, whilst, at Palo Alto, they had assumed an offensive attitude, aiming either to capture or destroy our army. In the passage of our troops between Matamoros and Point Isabel, the practiced eye of our military men often remarked the value of this ravine as a point of strength; and it had been already supposed that when the enemy halted, to resist our march, they would avail themselves of it for a battle ground. Hence this excellent position was not unknown to General Taylor, and he promptly prepared a combined attack of infantry, artillery and cavalry by which he might succeed in driving the American army like a wedge, through the narrow but only aperture that admitted its transit to our fort.