MANASSAS JUNCTION, VA., October 6, 1864.

(Received 10.10 p.m.)

Brigadier General D. C. McCALLUM:

Rebel force on the Gap road at Salem, between us and construction corps. All the material forwarded since yesterday morning is still this side of White Plains. Have just returned from White Plains, where I saw Colonel Gallupe with 600 men, who was compelled to fall back from Salem and intrench at White Plains. He ordered all the trains to be sent this side of Thoroughfare Gap, or to Manassas. Four succeeded in reaching here, and one engine and three cars are now on the way between the gap and Manassas. It is just reported that engine Grapeshot and twelve cars of railroad material are a perfect wreck at Thoroughfare Gap; report says the track was blown up, but I think the train run off the switch. The construction corps is out od material. Colonel Gallupe says he will endeavor to advance early in the morning, but he will take pike road. This course will not assist us much, as the rebel force at Salem is supposed to have destroyed the track. A strong force should advance on the railroad, and hold Salem until a connection is made with the construction corps. My first endeavor will be to clear the track at Thoroughfare Gap.

M. J. McCRICKETT,

Assistant Superintendent.

ALEXANDRIA, VA., October 6, 1864.

(Received 7.25 p.m.)

Colonel TAYLOR,

Assistant Adjutant-General:

COLONEL: The patrols report all quiet to-day. There has been some fighting with the railroad guard near Salem to-day. It is reported that Mosby has been re-enforced by two regiments of cavalry. This probably is the party attacking the railroad guard to-day.

Respectfully,

W. W. WINSHIP,

Captain and Acting Provost-Marshal-General.

HDQRS. DEPARTMENT OF WASHINGTON, 22ND ARMY CORPS,
October 6, 1864.

Colonel LAZELLE,

Commanding at Falls Church:

Collect all your available force (leaving a sufficient guard for your post and to patrol your front), and march with it to Alexandria, to take cars there for the front. Take 200 rounds of ammunition with you. Subsistence and forage will be taken from Alexandria.

Respectfully, yours,

C. C. AUGUR,

Major-General.

I leave for Rectortown to-night, and hope to see you there to-morrow. Make all possible haste.