All the troops with General Scott in the valley of Mexico, except a part of the division of General Quitman at San Augustin Tlalpam and the brigade of Garland (Worth's division) at San Antonio, were engaged at the battle of Contreras, or were on their way, in obedience to the orders of their chief, to reinforce those who were engaged.

The assault was made on the morning of the 20th, and in less than half an hour from the sound of the advance the position was in our hands, with many prisoners and large quantities of ordnance and other stores.

The brigade commanded by General Riley was from its position the most conspicuous in the final assault, but all did well, volunteers and regulars.
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.