From the point occupied by Garland's brigade we could see the progress made at Contreras and the movement of troops toward the flank and rear of the enemy opposing us. The Mexicans all the way back to the city could see the same thing, and their conduct showed plainly that they did not enjoy the sight. We moved out at once, and found them gone from our immediate front. Clarke's brigade of Worth's division now moved west over the point of the Pedregal, and after having passed to the north sufficiently to clear San Antonio, turned east and got on the causeway leading to Churubusco and the City of Mexico. When he approached Churubusco his left, under Colonel Hoffman, attacked a tete-de-pont at that place and brought on an engagement. About an hour after, Garland was ordered to advance directly along the causeway, and got up in time to take part in the engagement. San Antonio was found evacuated, the evacuation having probably taken place immediately upon the enemy seeing the stars and stripes waving over Contreras.
The troops that had been engaged at Contreras, and even then on their way to that battle-field, were moved by a causeway west of, and parallel to the one by way of San Antonio and Churubusco. It was expected by the commanding general that these troops would move north sufficiently far to flank the enemy out of his position at Churubusco, before turning east to reach the San Antonio road, but they did not succeed in this, and Churubusco proved to be about the severest battle fought in the valley of Mexico. General Scott coming upon the battle-field about this juncture, ordered two brigades, under Shields, to move north and turn the right of the enemy. This Shields did, but not without hard fighting and heavy loss. The enemy finally gave way, leaving in our hands prisoners, artillery and small arms. The balance of the causeway held by the enemy, up to the very gates of the city, fell in like manner. I recollect at this place that some of the gunners who had stood their ground, were deserters from General Taylor's army on the Rio Grande.
Both the strategy and tactics displayed by General Scott in these various engagements of the 20th of August, 1847, were faultless as I look upon them now, after the lapse of so many years. As before stated, the work of the engineer officers who made the reconnoissances and led the different commands to their destinations, was so perfect that the chief was able to give his orders to his various subordinates with all the precision he could use on an ordinary march. I mean, up to the points from which the attack was to commence. After that point is reached the enemy often induces a change of orders not before contemplated. The enemy outside the city outnumbered our soldiery quite three to one, but they had become so demoralized by the succession of defeats this day, that the City of Mexico could have been entered without much further bloodshed. In fact, Captain Philip Kearneyafterwards a general in the war of the rebellionrode with a squadron of cavalry to the very gates of the city, and would no doubt have entered with his little force, only at that point he was badly wounded, as were several of his officers. He had not heard the call for a halt.