GREENCASTLE, August 21, 1864.

Major JOHN S. SCHULTZE,

Assistant Adjutant-General:

The signal officer on North Mountain reports that he hears quite a rapid cannonading in the direction of Martinsburg. Probably an engagement is progressing in the Valley.

A. M. THAYER,

Lieutenant and Signal Officer.

HALLTOWN, VA., August 22, 1864-10.30 p.m.

Lieutenant General U. S. GRANT:

Yesterday morning the enemy crossed Opequon Creek at different points in the vicinity of Smithfield or Middleway and advanced on my position at Welch's Spring, about two miles west of Charlestown. Skirmishing took place during the day in front of both General Crook's command and the Sixth Army Corps. The skirmishing was at one time rather sharp in front of the latter command, as the line was pressed forward and drove the enemy from a crest in our front which they occupied early in the day. The cavalry skirmished some with the enemy at Berryville and Summit Point; this, however, did not amount to much. As my position at best in front of Charlestown was a bad one, and much being dependent on this army, I withdrew my command without loss or opposition last night and took up a new line in front of Halltown. This morning the enemy followed my rear guard and we have been skirmishing with them during the day. My loss yesterday was about 275. None of the enemy have crossed the river. Various reports have come to me in reference to a column of the enemy being at Culpeper and Warrenton, but I place no reliance on the reports. We have disposed of quite a number of Mosby's men.

P. H. SHERIDAN,

Major-General.

[AUGUST 22, 1864.-For Sheridan to Halleck, reporting operations, &c., see p. 19.]

HARPER'S FERRY, W. VA., August 22, 1864-1 p.m.

(Received 3.30 p.m.)

Honorable EDWIN M. STANTON,

Secretary of War:

I have just returned from the front, where I traversed the entire line. The left of the infantry rests to the left of Charlestown pike and over a mile beyond Halltown. The right is almost directly west of Harper's Ferry, and about two miles from Bolivar Heights. The line runs along a commanding ridge which overlooks a broad valley beyond, and is a position of great natural strength. The intervals to the left and right, connecting the rivers, say a mile each, are not so strong, but the enemy could hardly succeed in a flank movement. The enemy seems to be along the Charlestown pike, but in what force not known. His infantry drove our cavalry this morning after the retrograde movement began. Merritt has been sent up the Potomac toward Shepherdstown to look after the enemy. Scouts report no enemy yesterday