General Burnside, and my headquarters were located there until the conclusion of the action. General Sturgis Had left his camp at 1 p. m., and reached the scene of action about 3.30 p. m. Clark's battery, of his division, was sent to assist Cox's left, by order of General Reno, and two regiments (Second Maryland and Sixth New Hampshire) were detached by General Reno and sent forward a short distance, on the left of the turnpike. His division was formed in rear of Willcox's and Rodman's division was divided; Colonel Fairchild's brigade being placed on the extreme left, and Colonel Harland's, under General Rodman's personal supervision, on the right.

My order to move the whole line forward and take or silence the enemy's batteries in front was executed with enthusiasm. The enemy made a desperate resistance, charging our advancing lines with fierceness, but they were everywhere routed, and fled.

Our chief loss was in Willcox's division. The enemy's battery was found to be across a gorge and beyond the reach of our infantry, but its position was made untenable, and it was hastily removed and not again put in position near us; but the batteries across the gap still kept up a fire of shot and shell.

General Willcox praises very highly the conduct of the Seventeenth Michigan in this advance-a regiment which had been organized scarcely a month, but which charged the advancing enemy in flank in a manner worthy of veteran troops; and also that of the Forty-fifth Pennsylvania, which bravely met them in front.

Cook's battery now reopened fire. Sturgis' division was moved to the front of Willcox's, occupying the new ground gained on the further side of the slope, and his artillery opened on the batteries across the gap. The enemy made an effort to turn our left about dark, but were repulsed by Fairchild's brigade and Clark's battery.

At about 7 o'clock the enemy made another effort to regain the lost ground, attacking along Sturgis' front and part of Cox's. A lively fire was kept up until nearly 9 o'clock, several charges being made by the enemy and repulsed with slaughter, and we finally occupied the highest part of the mountain.

General Reno was killed just before sunset, while making a reconnaissance to the front, and the command of the corps devolved upon General Cox. In General Reno the nation lost one of its best general officers. He was a skillful soldier, a brave and honest man.

There was no firing after 10 o'clock, and the troops slept on their arms ready to renew the fight at daylight, but the enemy quietly retired from our front during the night, abandoning their wounded, and leaving their dead in large numbers scattered over the field.

While these operations were progressing on the left of the main column, the right, under General Hooker, was actively engaged. His corps left the Monocacy early in the morning, and its advance reached the Catoctin Creek about 1 p. m. General Hooker then went forward to examine the ground.

At about 1 o'clock General Meade's division was ordered to make a diversion in favor of ReNumbers The following is the order sent:

September 14-1 p. m.

Major-General HOOKER:

GENERAL: General Reno requests that a division of yours may move up on the right (north) of the main road. General McClellan desires you to comply with this request, holding your whole corps in readiness to support the movement, and taking charge of it yourself. Sumner's and Bank's corps have commenced arriving. Let General McClellan be informed as soon as you commence your movement.

GEO. D. RUGGLES,

Colonel, Assistant Adjutant-General, and Aide-de-Camp.