Corps commanders will hold their commands in readiness at a moment's notice, and, upon receiving orders to march against the enemy, their trains (ammunition wagons excepted) must be parked in the rear of the place of concentration. Ammunition wagons and ambulances will alone be permitted to accompany the troops. The men must be provided with three day's rations in haversacks, and with 60 rounds of ammunition in the boxes and upon the person. Corps commanders will avail themselves of all the time at their disposal to familiarize themselves with the roads communicating with the different corps. By command of Major-General Meade:

S. WILLIAMS,

Assistant Adjutant-General.

Headquarters Army of the Potomac,

June 30, 1863-7. 40 a. m.

Major General JOHN. F. REYNOLDS:

I am directed by the commanding general to inform you that General Gregg reports the presence of a large cavalry force of the enemy at Westminster yesterday afternoon and last night. It is supposed this cavalry force is making for Littlestown. A large force of our own cavalry must now be in close proximity to the enemy.

Very respectfully, &c.,

S. WILLIAMS,

Assistant Adjutant-General.

Headquarters First Corps,

June 30, 1863.

Major-General HOWARD,

Commanding Eleventh Corps:

Buford is in Gettysburg, and found a regiment of rebel infantry advancing on the town, which retired as he advanced, and he reports Anderson's division marching on Mummasburg, and passing off in the direction of Berlin. I forwarded the dispatches to Meade. Buford also sent a regiment to Fairfield, on the road leading from Moritz Tavern in that direction. My headquarters are at Moritz Tavern. I have one division and a battery on the Gettysburg road, one division on the road to Fairfield from here, and one in reserve on the Gettysburg road.

Yours, &c.,

JOHN F. REYNOLDS,

Major-General of Volunteers, Commanding.

[P. S.] - I do not believe the report of their marching on Berlin, which would lead them direct to York. The enemy are evidently marching out into this Valley, but whether it is for the purpose of going to York or to give us battle, I cannot say.

Headquarters LEFT WING,

June 30, 1863.

Major-General BUTTERFIELD,

Chief of Staff, Army of the Potomac:

I have forwarded all the information to you that I have been able to gain to-day. I think if the enemy advances in force from Gettys-