The attack was made after a march during the entire night in a drenching rain. The surprise was complete. Fifteen rebels killed. The gallant Colonel Kelley, of the First Virginia Volunteers, I fear, is mortally wounded. No other important casualties on our side.

The dispatch from General Morris informs me that the troops at last advices were in hot pursuit of the rebels.

GEO. B. McCLELLAN,

Major-General, Commanding.

Colonel E. D. TOWNSEND, Assistant Adjutant-General.

HEADQUARTERS DEPARTMENT OF THE OHIO,
Cincinnati, Ohio, June 10, 1861.

SIR: Inclosed I have the honor to forward the report of Brigadier General T. A. Morris, Indiana Volunteers, commanding the U. S. volunteer forces in the vicinity of Grafton, Va., giving a detailed account of the operations connected with the attack and occupation of Philippi.

After the two branches of the Baltimore and Ohio Railroad leading from Wheeling and Parekrsburg had been secured and Grafton occupied by our troops, I learned that the insurgents had retreated to Philippi and received very considerable accession to their numbers.

To prevent their further outrages upon the railroads or upon the property of loyal citizens, I directed an immediate movement to dislodge and disperse them from their new position. This was executed under the orders of General Morris, Colonel Keley, of the First Virginia Volunteers, having the immediate command of the attacking columns; and the result as will be seen from General Morris' report, was in many respects highly creditable to the troops engaged, and perfectly successful. The insurgents, about 2,000 in number, were surprised in their camp routed, and in great confusion driven before our troop for several miles towards Beverly.

Although quite a number of them were killed and wounded and a large portion of their munitions captured, yet it is much to be regretted that exhausted condition of our men, consequent upon a long night march through mud and rain prevented them from overtaking and capturing the mass of the fugitives. It is believed, however, that the effect of this decisive engagement will be to inspire the Union people of the country with confidence in our ability to afford them protection.

Had the attack been supported by a few companies of cavalry, it is probable that many of the enemy would have been captured or cut to pieces. As I have no available troops of that description in my department, I would very respectfully urge upon the consideration of the general commanding the importance of a mounted force (regular cavalry if they can be furnished) to insure the success of future operations in this department.

Colonel Kelley, who conducted the movement on Phillippi with marked ability and zeal, received a severe wound early in the action, which at the time was supposed to be mortal, but i am now happy today that he is considered out of danger. From the moment he received my orders at Wheeling to move on Grafton up to the time he was wounded he has exhibited in an eminent degree the qualities of an efficient commander, and I take this opportunity of renewing my recommendation for his promotion to the rank of brigadier-general in the Virginia Volunteer Militia.

Colonel Dumont deserves great credit for his conduct in the attack and pursuit of the rebels.