Headquarters Army of Occupation
Camp near Matamoras, May 16, 1846.

Sir: - I have now the honor to submit a more detailed report of the action of the 8th instant.

The main body of the army of occupation marched under my immediate orders from Point Isabel, on the evening of the 7th May, and bivouacked 7 miles from that place.

Our march was resumed the following morning. About noon, when our advance of cavalry had reached the water-hole of "Palo Alto," the Mexican troops were reported in our front, and were soon discovered occupying the road in force. I ordered a halt upon reaching the water, with a view to rest and refresh the men, and form deliberately our line of battle. The Mexican line was now plainly visible across the prairie, and about three-quarters of a mile distant. Their left, which was composed of a heavy force of cavalry, occupied the road resting upon a thicket of chapparal, while masses of infantry were discovered in succession on the right, greatly outnumbering our own force.

Our line of battle was now formed in the following order, commencing on the extreme right: 5th infantry, commanded by Lieutenant Colonel McIntosh; Major Ringgold's artillery; 3d infantry, commanded by Captain L. M. Morris; two 18-pounders, commanded by Lieutenant Colonel Garland; and all the above corps, together with two squadrons of dragoons under captains Ker and May, composed the right wing, under the orders of Colonel Twiggs. The left was formed by the battalion of artillery, commanded by Lieutenant Colonel Childs, Captain Duncan's light artillery, and the 8th infantry, under Captain Montgomery - all forming the 1st brigade, under command of Lieutenant Colonel Belknap. The train was parked near the water, under direction of Captains Crosman and Myers, and protected by Captain Ker's squadron.

About 2 o'clock we took up the march by heads of columns, in the direction of the enemy, the 18-pounder battery following the road. While the columns were advancing, Lieutenant Blake, topographical engineers, volunteered a reconnoisance of the enemy's line, which was handsomely performed, and resulted in the discovery of at least two batteries of artillery in the intervals of their cavalry and infantry. These batteries were soon opened upon us, when I ordered the columns halted and deployed into line, and the fire to be returned by all our artillery. The 8th infantry, on our extreme left, was thrown back to secure that flank. The first fires of the enemy did little execution, while our 18-pounders and Major Ringgold's artillery soon dispersed the cavalry which formed his left. Captain Duncan's battery, thrown forward in advance of the line, was doing good execution at this time. Captain May's squadron was now detached to support that battery and the left of our position. The Mexican cavalry, with two pieces of artillery, were now reported to be moving through the chapparal to our right, to threaten that flank or make a demonstration against the train. The 5th infantry was immediately detached to check this movement, and supported by Lieutenant Ridgely, with a section of Major Ringgold's battery and Captain Walker's company of volunteers, effectually repulsed the enemy - the 5th infantry repelling a charge of lancers, and the artillery doing great execution in their flanks. The 3d infantry was now detached to the right as a still further security to that flank yet threatened by the enemy. Major Ringgold, with the remaining section, kept up his fire from an advanced position, and was supported by the 4th infantry.

The grass of the prairie had been accidentally fired by our artillery, and the volumes of smoke now partially concealed the armies from each other. As the enemy's left had evidently been driven back and left the road free, and as the cannonade has been suspended, I ordered forward the 18-pounders on the road nearly to the position first occupied by the Mexican cavalry, and caused the 1st brigade to take up a new position still on the left of the 18-pounder battery. The 5th was advanced from its former position, and occupied a point on the extreme right of the new line. The enemy made a change of position corresponding to our own, and, after a suspension of nearly an hour, the action was resumed.

The fire of artillery was now most destructive; openings were constantly made through the enemy's ranks by our fire, and the constancy with which the Mexican infantry sustained this severe cannonade was a theme of universal remark and admiration. Capt. May's squadron was detached to make a demonstration on the left of the enemy's position, and suffered severely from the fire of artillery to which it was for some time exposed.

The 4th infantry, which had been ordered to support the 18-pounder battery, was exposed to a most galling fire of artillery, by which several men were killed, and Capt. Page dangerously wounded. The enemy's fire was directed against our 18-pounder battery, and the guns under Major Ringgold in its vicinity. The Major himself, while cooly directing the fire of his pieces, was struck by a cannon ball and mortally wounded.

In the mean time the battalion of artillery under Lieut. Col. Childs had been brought up to support the artillery on our right. A strong demonstration of cavalry was now made by the enemy against this part of our line, and the column continued to advance under a severe fire from the 18-pounders. The battalion was instantly formed in square, and held ready to receive the charge of cavalry; but when the advancing squadrons were within close range, a deadly fire of cannister from the 18-pounders dispersed them. A brisk fire of small arms was now opened upon the square, by which one officer, Lieut. Luther, 2d artillery, was slightly wounded; but a well-directed volley from the front of the square silenced all further firing from the enemy in this quarter. It was now nearly dark, and the action was closed on the right of our line - the enemy having been completely driven back from his position, and foiled in every attempt against our line.

While the above was going forward on our right, and under my own eye, the enemy had made a serious attempt against the left of our line. Captain Duncan instantly perceived the movement, and, by the bold and brilliant maneuvering of his battery, completely repulsed several successive efforts of the enemy to advance in force upon our left flank. Supported in succession by the 8th infantry and by Capt. Ker's squadron of dragoons, he gallantly held the enemy at bay, and finally drove him with immense loss from the field. The action here, and along the whole line, continued until dark, when the enemy retired into the chapparal in rear of his position. Our army bivouacked on the ground it occupied. During the afternoon the train had been moved forward about half a mile and was parked in rear of the new position.

Our loss this day was nine killed, forty-four wounded, and two missing. Among the wounded were Major Ringgold, who has since died, and Captain Page, dangerously wounded; Lieut. Luther slightly so. I annex a tabular statement of the casualties of the day.

Our own force engaged is shown by the field report (herewith) to have been 177 officers and 2,111 men; aggregate 2,288. The Mexican force, according to the statements of their own officers taken prisoner in the affair of the 9th, was not less than 6,000 regular troops, with 10 pieces of artillery, and probably exceeded that number; the irregular force not known. Their loss was not less than 200 killed and 400 wounded - probably greater. This estimate is very moderate, and formed upon the number actually counted upon the field, and upon the reports of their own officers.

As already reported in my first brief despatch, the conduct of our officers and men was everything that could be desired. Exposed for hours to the severest trial, a cannonade of artillery, our troops displayed a coolness and constancy which gave me, throughout, the assurance of victory.

I purposely defer the mention of individuals until my report of the action of the 9th, when I will endeavor to do justice to the many instances of distinguished conduct on both days. In the mean time I refer, for more minute details, to the reports of individual commanders.

I am, sir, very respectfully, your obedient servant,

Z. TAYLOR,
Brevet Brig. Gen. U.S.A., commanding.