Immediately after that first fire, a portion of the force with me on the roof became engaged with the enemy who appeared on house tops in rear of their battery. We soon drove them from their position. The other portion of our men fell back to the stairs, made their way to the lower story, broke open the thick, heavily barred, strong door, passed into the street, entered the abandoned works, and pursued the enemy. In the meantime, some of our troops from the right of the causeway had come forward and, a very small number of them, were slightly in advance of us in reaching the abandoned battery. Colonel Garland, commander of the first brigade of Worth's division, on the right of the causeway, says, in his official report: "The enemy then took position at the Garita San Cosme, where they were supported by two pieces of artillery which raked the streets with grape and canister. Finding a secure position to the right of the second defence, [about 350 yards in front of the Garita], I reorganized the command as it came up; mounted a howitzer on the top of a convent, which, under the direction of Lieutenant [U. S.] Grant, Quartermaster, 4th Infantry, and Lieutenant Lendrum, 3rd Artillery, annoyed the enemy considerably. About this time, report was made to me that considerable progress had been made by the troops on the other side of the street by means of crowbars and pickaxes, working through houses and yards. This caused me to watch closely for the first movement of the enemy indicative of retreat. The moment this was discovered, the 4th Infantry, followed by detachments of the 2nd and 3rd Artillery, under Colonel Belton, rushed up the road, when they entered the work simultaneously with the forces operating to the right and left, Captain McKenzie's storming party slightly in advance". (Ex. Doc. No. 1, Appendix, p. 170.) Referring to this operation, General Worth, in his official report, says; "the moment had now arrived for the final and combined attack upon the last stronghold of the enemy in my quarter; it was made, by our men springing, as if by magic, to the tops of the houses into which they had patiently and quietly made their way with the bar and pick, and to the utter surprise and consternation of the enemy, opening upon him, within easy range, a destructive fire of musketry. A single discharge, in which many of his gunners were killed at their pieces, was sufficient to drive him in confusion from the breastworks; when a prolonged shout from our brave fellows announced that we were in possession of the Garita of San Cosme and already in the city of Mexico". (Ex. Doc. No. 1, p. 392.)