After great labor, I have succeeded in crossing my troops . I had very rapid, which renders the passage both difficult and dangerous, yet we have lost neither man nor horse . I sent a cavalry scout to North Mountain Station this morning . A short distance beyond the station, on the Martinsburg road, they surprised a rebel cavalry company and captured 17 prisoners, pursuing the balance to within 3 miles of Martinsburg . The prisoners represent that Hampton's brigade is in or near Martinsburg . Heavy firing was heard by us yesterday in that direction . Will you please advise me where it was, if you have been informed? My advance occupies North Mountain Station, The telegraph wire repaired to-day, and in working order to that point, I will move forward with my whole force as soon as I can get my transportation across the river . I have had the canal repaired from Cumberland to Hancock, and we are getting our supplies as far as the latter place by canal . The railroad company are progressing rapidly with the repairs of the road east of Cumberland . I think the road will be open for trade and travel as far east as Martinsburg in ten days.

B. F. KELLEY,

Brigadier-General.

Colonel E. D. TOWNSEND,

Assistant

Adjutant-General.

- CHEERY RUN, VA., July 18, 1863.

I have just returned from Hedgesville . My cavalry had a brisk skirmish this p. m. with enemy between Hedgesville and Martinsburg. Another detachment captured this a. m., on Back Creek, forage train of General Load's [Rodes?] command, which is encamped near Bunker Hill . Lee is reported there also . I have ordered General Averell to advance to-morrow as far as Martinsburg, and, if enemy is not found too strong, to drive him out . Will you please advise me if your information regarding Lee's army is in accordance with mine, as I desire to be cautions with my small force?

B. F. KELLEY,

Brigadier-General.

The ADJUTANT-GENERAL .

- BACK CREEK, Va., July 20, 1863.

General Averell advanced yesterday toward Martinsburg. A few miles this side of town he encountered pickets of Hamton's brigade, which occupies the town . In obedience to my orders not to bring on a general engagement, lest Ewel should come to Hampton's support, General Averell fell back slowly and cautiously, pursued by the enemy, until he reached infantry and artillery posted at Hedgesville, when he turned and drove him back, killing and wounding several men and horses and capturing about 20 prisoners . Our casualties were 6 men wounded . All quiet this morning .

B. F. KELLEY,

Brigadier-General

Brigadier-General CULLUM. Chief of Staff, Washington, D. C.