INDIAN SPRINGS, MD., July 11, 1863.

Colonel E. D. TOWNSEND,

Assistant Adjutant-General:

I moved to this place last night. It is at the west base of North Mountain. Will cross the mountain to-night, and camp on the east base. My force is small, but I cannot well be driven out of the mountain. I am blockading with fallen timber all the roads between the turnpike and the river, so as to prevent any attachments making their escape to fords above. My cavalry scouts had a spirited skirmish with the enemy's cavalry near Clear Spring yesterday; several wounded on both sides. River falling slowly. Telegraph line repaired to Cherry Run, opposite this point. Weather cloudy, and strong indications of rain. General Averell has not yet come up. His movement is exceedingly slow. I could now use his cavalry to a good purpose.

B. F. KELLEY,

Brigadier-General.

JULY 11, 1863.

General NAGLEE,

Commanding Harper's Ferry:

I am directed by the major-general commanding to say that the engineer troops at Harper's Ferry are there for the purpose of being used in an emergency, when they will be required to work day and night. It is important that they should be kept fresh, and he directs, therefore, that you will not call upon them excepting in case of an emergency, such as that of an actual attack upon your post. Lieutenant Mackenzie has been sent for the purpose of laying out such works as you may deem necessary, and in such work will, no doubt, obtain all the aid necessary from the engineer troops.

A. A. HUMPHREYS,

Major-General, and Chief of Staff.

OFFICE OF THE CHIEF QUARTERMASTER,

Camp of the Antietam, Md., July 11, 1863.

Brigadier General S. WILLIAMS,

Adjutant-General, Army of the Potomac:

GENERAL: Since the issue of my circular of March 10, 1863, regulating the allowance of transportation and camp and garrison equipage to this army, several orders have been issued from this office changing it, and I have found it necessary in the late movements of our army to make still further changes.

I have the honor, therefore, to request that my circular may be canceled, and the following allowance of transportation and camp and garrison equipage may be established, and that order regulating it may be issued from your office:

I. For headquarters Army of the Potomac, including the chiefs of the various staff departments, with their aides-de-camp, employees, servants, retainers, and camp followers, such wagons for baggage and supply trains, ambulances, spring wagons extra saddle-horses, with equipments complete, for contingent wants, and camp equipage, as may be from time to time actually required, provided it does not exceed the allowance as established be existing orders.