Geary's signal officer reports having observed the light of a large fire last night in the direction of Rough and Ready Station just before the storm came on.

GEO. H. THOMAS,

Major-General.

STANLEY'S HEADQUARTERS, August 20, 1864.

General THOMAS:

I have been out on the left since 3 a. m., and have just returned. We drove the enemy's skirmishers back one mile and found the right of his infantry line. Took 8 prisoners from Strahl's brigade, and they report that Ferguson's brigade of cavalry left their right at daylight yesterday a. m., and only the two regiments of new Georgia cavalry are now on the right of the infantry. I was just witting a full report when your dispatch was received. Will start if off in a few minutes.

D. S. STANLEY,

Major-General.

HEADQUARTERS FOURTH ARMY CORPS, Near Atlanta, Ga., August 20, 1864-10.30 a. m.

Brigadier-General WHIPPLE,
Chief of Staff:

GENERAL: I have the honor to report that the reconnaissance I proposed making last evening was accomplished this morning by Brigadier-General Grose, with six regiments of his brigade, Colonel Opdycke's brigade supporting his left flank. The course of march was nearly due south from the burnt house on the railroad. The rebel skirmishers were driven back about a mile, when they made a stand in the works at the angle occupied by the Seventeenth Corps some weeks ago. As the brigade was advanced a good distance beyond support it was not deemed prudent to advance farther. Our losses were; Major Carter, Ninth Indiana, badly contested by a spent ball; 1 man mortally and 2 severely wounded. We captured 8 men of the Forty-first Tennessee Infantry, Strahl's brigade, Cheatham's division. From these we learned that we struck the extreme right of the brigade and the right of the rebel army, excepting the two new regiments of Georgia calvary, who scampered off as soon as our skirmishers met them. The prisoners state that Ferguson's brigade of cavalry left their (Strahl's) right at daylight yesterday morning. The prisoners confirm the report of the putting up of the big guns on the new fort southeast of the city. They observation leads to, that the rebels have a line of works covering the south of the city. I do not think an attack upon the enemy's right could be made decisive with less than a corps, and then not certainly, as an attacking force would meet several successful works. Strahl's brigade, however, could be sent flying with a good division. The rebels have re-enforced their lines in front of us with additional militia. I do not know the country, but I believe Miller's brigade of cavalry could go around and smash up the Georgia cavalry. They won't fight much. My men charged the enemy behind works and behaved well. The Ninth Indiana took the prisoners.

Your obedient servant,

D. S. STANLEY,

Major-General.