the Third Infantry in the churchyard.  In the night Captain R.E.  Lee arrived, bearing a letter from General Scott asking to be informed of affairs beyond the pedregal.  The information sought for was given, and Captain Lee was requested to inform General Scott of General Smith’s intention to attack Valencia next morning, and asking that a diversion be made on Valencia’s front.  General Shields arrived at midnight, and was left to hold the village and cut off the enemy’s retreat.  In the meantime Colonel Ransom abandoned Padierna, which was soon afterward occupied by General Valencia’s forces, but not without stout resistance by the small detachment left there.

At nightfall General Santa Anna fell back to San Angel, but failed to give notice of the movement to General Valencia.  Mexican history states that at 9 P.M.  Ramero and Del Rio arrived at Valencia’s headquarters and delivered an order from Santa Anna to Valencia to retire.  General Solos, however, who was present, denies this, saying that the order was qualified by one to spike the guns, destroy the ammunition, and saving only what could be safely transported.  General Valencia declined to obey the order.  At 2.30 P.M. of August 20th Smith’s troops moved to reach Valencia’s rear.  Riley’s brigade and Cadwallader’s followed this movement.  General Shields with the New York regiment of Colonel Ward B. Burnett and the South Carolina regiment under Colonel Pierce M. Butler remained at the village, to intercept and cut off the enemy’s retreat and to prevent re-enforcements from reaching the Mexicans.

The night was intensely dark, and the streets of the village were very narrow, cut into gullies and very muddy.  A heavy rain was pouring down, and the march was made under difficulties and necessarily slow.  General Smith’s position was on an eminence about one thousand yards from the enemy’s works, from which point he made the attack.  Riley moved up the ravine to a slope leading to a high point of the ridge and attacked the enemy some eight hundred yards distant.  Cadwallader followed Riley, and the Mounted Rifles and Engineer Company moved to a position in rear of the force confronting Riley.  The Third Infantry and First Artillery were held in reserve.  The attack was made as ordered by General Smith, and the enemy fled, pursued by Riley, the Mounted Rifles, and Engineers.

The Third Infantry and First Artillery, held in reserve, were attacked by a force of cavalry, which was driven off, and Valencia was completely routed.  General Shields, who held the village, seized the main road and cut off retreat in that direction.  The enemy fled in the greatest confusion.  The battle of Contreras was one of the most brilliant victories of the war.  It opened the road to the City of Mexico.  Seven hundred of the enemy were killed, eight hundred and thirteen prisoners were captured, including eighty-eight officers, of whom four were generals; many standards, twenty-two pieces of brass cannon, a large number of stands of small arms, seven hundred pack mules, many horses, and large quantities of ordnance stores were added to the outfit of the American army.