once since I wrote you last in regard to the fight this morning. General Crook says when he left Stevens' Gap Colonel Post had no orders to leave the gap. I have sent through to Post all dispatches sent me yesterday. I learn from signal officer that Watkins' brigade is coming down the gap. I sent a letter addressed to Colonel P. at the same time I sent Colonel Watkins an order to come up. Did not know the contents; suppose it was an order to come here, however.

I am, your obedient servant,

ROBT. B. MITCHELL.

GENERAL THOMAS' HEADQUARTERS,

Battle-field, Five Miles South of Rossville,

September 20, 1863-3.45 p.m.

General ROSECRANS:

I arrived here ten minutes ago, via Rossville. General Thomas has Brannan's, Baird's, Reynolds', Wood's, Palmer's, and Johnson's divisions with Thomas, and is fighting terribly on the right. Sheridan is in with the bulk of his division, but in ragged shape, though plucky and fighting. General Thomas holds nearly his old ground of this morning. Negley was coming down on Rossville from the road leading from where we saw the trains in our route, and I sent word to him to cover the retreat of trains through Rossville. I also met the Fourth U. S. Battery at that place, and posted it as a reserve in case of need. As I turned in from the Rossville road to General Thomas' line I was opened upon by a rebel battalion. One orderly killed; Captain Gaw's horse killed and my own wounded.

The hardest fighting I have seen to-day is now going on here. I hope General Thomas will be able to hold on here till night, and will not need to fall back farther than Rossville; perhaps not any. All fighting men should be stopped there, and the Dry Valley and Lookout roads held by them. I think we may in the main retrieve our morning disaster. I never saw better fighting than our men are now doing. The rebel ammunition must be nearly exhausted. Ours is fast failing. If we can hold out an hour more it will be all right. Granger thinks we can defeat them badly to-morrow if all our forces come in. I think you had better come to Rossville to-night and bring ammunition.

Very truly, yours.

J. A. GARFIELD,

Brigadier-General.

HDQRS. FIRST BRIGADE, SECOND CAVALRY DIVISION,
On Ringgold Road, September 20, 1863-3.50 p.m.

General GARFIELD:

SIR: Forrest (said to be about 1,500 strong) is immediately in my front skirmishing. I will endeavor to drive him.

Respectfully, &c.,

R. H. G. MINTY,

Colonel, Commanding.