The battle of Contreras and the subsequent advance upon San Angel and Coyoacan led to the evacuation of San Antonio. Whilst this was in progress, Clarke’s brigade, conducted by Captain Mason, of the engineers, made a flank movement to the left, and cut the enemy’s retreating column of three thousand in two, dispersing the rear portion and preventing its reaching the main body and entering into the subsequent fight. Worth, with both brigades, now pushed forward with great energy upon the heels of the other portion, till the column was arrested by a fire of grape from a strong bastioned field-work of fourteen feet relief and wet ditches in front, covering the passage of a canal, and somewhat in rear of the work attacked by Twiggs, and which, like the latter work, had not been noticed in the previous reconnoissances. Both brigades were formed in the cornfields on the right; the charge was ordered, Clarke in advance; and after a desperate but short conflict the work was carried at the point of the bayonet, the 6th infantry and 2d artillery particularly distinguishing themselves.
In the mean time Shields, in command of Shields’s and Pierce’s brigades, conducted by Captain Lee, the Palmetto regiment in advance, pursued a route to the left, and finally came in contact with the enemy near the hacienda on the great San Antonio causeway, a mile from the tête-de-pont. The enemy were in great force lining the causeway, and the lancers advancing towards the canal. The Palmettoes advanced most gallantly, led by their gallant colonel, Butler; but some hesitancy was manifested by the other commands, who retired under cover of the hacienda or crowded behind the Palmettoes. Notwithstanding the utmost exertions of the officers, a pause took place at good escopette range, and a considerable loss was experienced. The Palmettoes lost their colonel, shot dead, their lieutenant-colonel, wounded, four successive color-bearers, shot down, and nearly half their rank and file killed and wounded. Finally the movement was commenced, the enemy was charged through, and the causeway was filled with fugitives to the city.
The dragoons, who thus far had continued inactive, now took the causeway in pursuit, and the most gallant feat of the war was enacted. Captain Kearny, in advance with a squadron, pursued the fugitives to the very garita, where he charged directly up to a battery under a fire of grape, dismounted, calling upon his men to follow him, and entered the gorge of the work to take it by assault. Looking around, he found himself alone, the few men immediately following him having been shot down, and the remainder having retired in obedience to the return call from the rear, which for Kearny’s safety had just at this moment been inauspiciously sounded. Surrounded by a crowd of fugitives, who pressed too closely upon him to use their weapons, he retreated, making a passage with his sword, mounted a jaded Mexican horse, and commenced to retire. Finding that the sorry speed of the brute would long time expose him to the enemy’s grape, he dismounted and sought a better steed. Scarcely was he mounted when his arm was carried away by a grape; but he succeeded in making good his retreat. His first lieutenant, Ewell, had two horses shot under him, and his second lieutenant, Graham, was wounded in the hand.
This was the terrible and decisive conflict of the war, and was a case of a combined movement of all the divisions. The enemy’s intrenched works were carried at the point of the bayonet. Surrounded on all sides, the strong defensive building attacked by Twiggs was obliged to surrender; the reserves, vigorously pushed, fled from the field; and the army, which in the morning was estimated to be 27,000 strong, scarcely presented in the evening a sorry array of 4000. We could have entered the city the same day had we chosen. But our troops had made extraordinary exertions, our casualties were great, and the general determined to operate against the city after deliberately weighing its capacity for defense.
After this disastrous defeat of the enemy General Scott rode through his lines, addressing with terseness, brevity, and feeling the troops as he passed them, who received him with great enthusiasm, and exhibiting all that moderation and equanimity which has eminently characterized his course throughout this campaign. Towards night he returned to his quarters at San Augustin.
All the divisions suffered in nearly equal proportion, the casualties amounting to 1066, of which about one fourth were killed or permanently disabled.
The 1st artillery suffered most severely in officers, losing in all the battles five gallant officers, Captains Capron and Burke, Lieutenants Irons, Johnson, and Hoffman.
It is probable the same and perhaps more decisive results could have been effected, and with far less loss, had Twiggs and Worth stopped in mid-career, and an hour been taken to reconnoitre the enemy’s position. Pillow and Shields with Garland’s brigade and Duncan’s battery demonstrating in front, Twiggs’s whole division with Taylor and the howitzer battery on the enemy’s right, Clarke’s brigade on their left, both making considerable detours, Clarke as a demonstration, Twiggs the great attack, the causeway might have been gained; Taylor’s battery sent thundering on the enemy’s rear, with Harney’s horse and Riley’s brigade cutting off all hope of succor, the enemy’s works and the reserves inclosed by our troops must have immediately surrendered. Then, the prisoners and their works left in charge of Pillow, all the other divisions united could have been pushed forward in support of Riley, and the city could have been stormed with little or no loss.
This is expecting impossibilities. We knew nothing of the enemy’s works, but we saw them in full retreat, we pushed forward to cut off their retreat, and, coming upon the enemy’s intrenched position, we became engaged in the very act of reconnoitring it. The result was most glorious to our arms, and will, we trust, conclude the war.
Major Smith, the chief engineer, was present during the battle of Churubusco, and was distinguished for gallantry. He is suffering with the same disability as myself.