When the sun rose on the morning of the 9th a mist of mingled smoke and vapor hung over the battle field of Palo Alto, but, as the haze lifted from the levels, the Mexicans were perceived retreating by their left flank, in order, perhaps, to gain a more advantageous position on the road in which they might resist our progress towards Matamoros. This movement inspirited our troops, who, craving the interest of a new position, were loath to repeat the battle of yesterday on the same field. Accordingly General Taylor ordered the supply train to be parked at its position and left under the guard of two twelve-pounders and the fatal eighteens which had done such signal service on the 8th. The wounded men and officers were next despatched to Point Isabel, and we then moved across the Llano Burro towards the edge of the dense chapparal which extends for a distance of seven miles to the Rio Grande. The light companies of the first brigade under Captain Smith, of the second artillery; and a select detachment of light troops, all commanded by Captain McCall, were thrown forward into the thickets to feel the enemy and ascertain the position he finally took. In our advance we crossed the ground occupied by the Mexicans on the 8th where their line had been mowed by our artillery. Shattered limbs, riven skulls, slain and wounded horses, dying men, military accoutrements, gun stocks and bayonets lay strewn around, the terrible evidences of war and havoc. As our men pressed on they encountered, at every step, appeals to their humanity, from the famished and thirsty remnants of the Mexican army whose wounds did not permit them to advance with their compatriots; but it may be recorded to the honor of the troops, that our maimed enemies were in no instance left without succor, and that officers and men vied with each other in relieving their wants and despatching them to our hospitals. About three o'clock in the afternoon a report was sent from the scouts that the enemy were again in position on the road, which they held with at least two pieces of artillery. The command was immediately put in motion, and, about an hour after, came up with Captain McCall.