SHEPHERDSTOWN.

On the morning of the 20th, at 6.30 o'clock, I was directed by General Jackson to take my division and drive across the river some brigades of the enemy who had crossed during the night, driven off General Pendleton's artillery, capturing four pieces, and were making preparations to hold their position. Arriving opposite Boteler's Ford, and about half a mile therefrom, I formed my line of battle in two lines, the first the brigades of Pender, Gregg, and Thomas, under command of General Gregg, and the second, Lane (Branch's brigade), Archer, and Brockenbrough, under the command of General Archer. The enemy had lined the opposite hills with some seventy pieces of artillery, and the infantry who had crossed lined the crest of the high banks on the Virginia shore. My lines advanced simultaneously, and soon encountered the enemy. This advance was made in the face of the most tremendous fire of artillery I ever saw, and too much praise cannot be awarded my regiments for their steady, unwavering step. It was as if each man felt that the fate of the army was centered in himself. The infantry opposition in front of Gregg's center and right was but trifling, and soon brushed away. The enemy, however, massed in front of Pender, and, extending, endeavored to turn his left. General Pender became hotly engaged, and in forming Archer of his danger, he (Archer) moved by the left flank, and forming on Pender's left, a simultaneous, daring charge was made, and the enemy driven pell-mell into the river. Then commenced the most terrible slaughter that this war has yet witnessed. The broad surface of the Potomac was blue with the floating bodies of our foe. But few escaped to tell the tale. By their own account they lost 3,000 men, killed and drowned, from one brigade alone. Some 200 prisoners were taken. My own loss was 30 killed and 231 wounded; total, 261.

This was a wholesome lesson to the enemy, and taught them to know that it may be dangerous sometimes to press a retreating army. In this battle I did not use a piece of artillery.

My division performed its share in the destruction of the Baltimore and Ohio Railroad, and about November 1 took position at Castleman's Ferry, near Snicker's Gap.

On November 3, Archer's and Thomas' brigades being on picket at the ferry, with Pegram's and Latham's batteries, the enemy made an attempt to cross the river, but were handsomely repulsed by the Nineteenth Georgia and the batteries, with a loss of 200 men.

During this campaign the especial good conduct of Colonels Brewer, [F.] Mallory, [R. W.] Folsom, and Major C. C. Cole deserves mention. Captain Wright, of Georgia, commanding my escort, was invaluable to me, and proved himself a cool, clear-headed fighter.

My thanks are due my staff for their hearty co-operation and intelligent transmission of my orders under a fire frequently uncomfortably hot-Major R. C. Morgan, assistant adjutant-general; Major [R. J.] Wingate, Captain R. H. T. Adams, signal officer; Lieutenant Murray [F.] Taylor, aide-de-camp, and Lieutenant [C. H.] Camfield,of my escort.

My loss during this series of battles was 348 killed and 2,209 wounded; total, 2,557.

I am, sir, very respectfully, your obedient servant,

A. P. HILL,

Major-General, Commanding Light Division.

Lieutenant Colonel C. J. FAULKNER,

Assistant Adjutant-General, Second Army Corps.