WINCHESTER, VA., October 29, 1864-9 a. m.

(Received 5 p. m.)

Major-General HALLECK,

Chief of Staff:

I rode to this place last night, expecting to find Colonel Alexander, or Thom, here, as they promised to be. I want the railroad pushed as my horses are suffering very much. I cannot supply by wagon. All was quiet when I left last night. No enemy within thirty miles. I the proper guard for working parties on the railroad cannot be furnished form Harper's Ferry, I will send from here.

P. H. SHERIDAN,

Major-General.

WAR DEPARTMENT, Washington City, October 29, 1864.

General JOHN A. RAWLINS,

Chief of Staff of Lieutenant-General Grant, City Point, Va.:

MY DEAR RAWLINS: I have lately been in the Shenandoah Valley, and send, for the general's consideration and yours, the result of my observations and of my conversations with Sheridan and other officers.

The active campaign in the Valley seems to be over for this year. The enemy is so decidedly beaten and scattered, and driven so far to the south, that he can scarcely be expected to collect his forces for another attempt during the present season. Besides, the devastation of the Valley, extending as it does for a distance of about 100 miles, renders it almost impossible that either the Confederates or out own forces should make a new campaign in that territory; and when Sheridan has completed the same process down the Valley tot he vicinity of the Potomac, and when the stores of forage which are yet to be found in Loudoun County and in some parts of Fauqier, and the animals that are still there are all destroyed or removed, the difficulty of any new offensive operations on either side will have been greatly increased.

The key to the Valley is, in Sheridan's judgment, the Opequon Creek, which is rather a deep canon than an ordinary water course. Sheridan's idea I understand to be to fall back to the proper defensive point upon that creek, and there to construct fortifications which will effectually cover the approach to the Potomac.

The opening of the winchester railroad to this point-an affair of not more than eight or ten days-will render it possible to supply the garrison with safety and economy; and this line of railroad communication can be defended with a less force than is now required to escort the wagon trains which supply Sheridan from Martinsburg and Harper's Ferry. As soon as this is accomplished say by the 10th of November, it will, in my judgment, be perfectly practicable to hold the Valley and to defend the approach to the Potomac and to the railroad int hat direction whit from 5,000 to 10,000 men-that is to say, with the infantry and calvary forces of thee Department of West Virginia-thus leaving and Sixth and Nineteenth Corps disposable for operations elsewhere.

A movement against Gordonsville and the Orange and alexandria Railroad cannot well be made from the Valley, but, if it is decided upon, must, I think, be undertaken by way of Manassas and Culpeper. It is plain that, as soon as Sheridan has taken up the purely defensive position on the Opequon Creek, of which I have spoken above, and has got himself properly fortified, it will be a great deal easier for him to march