HEADQUARTERS THIRTEENTH ARMY CORPS, Five-Mile Creek, May 11, 1863.

Major General U. S. GRANT,
Commanding Department of the Tennessee:

GENERAL: I venture to make a suggestion, which, of course, will be only estimated according to its value. Reports and what should be the policy of the enemy combine to warn us that he will attempt to cross the Big Black in our rear, and isolate us by cutting our communications. Having steamboats at his disposal, he could rapidly cross troops for that purpose. In view of this danger, I would inquire whether it would not be advisable for us to shift our advancing columns farther to the left, resting our left flank upon the Big Black? By so doing, we could prevent the descent of the enemy. Steamers could effectually guard the river and avoid the disadvantage of detaching forces to command both Hall's and Baldwin's Ferries.

If his approach should be adopted, and I should continue on the left, I could move by two roads to Fourteen-Mile Creek, from Cayuga to Baldwin's Ferry, and from Old Auburn to a point on the road from New Auburn to Baldwin's Ferry. The rebel map sent this morning will illustrate these roads. General Sherman's corps could move to the intersection of Fourteen-Mile Creek by the road leading from the vicinity of Old Auburn to Edwards Station, and General McPherson could move still to the right of General Sherman.

If the object of the movement so far t the right is to threaten or destroy the railroad in the direction of Jackson, could that not be done by ba detachment suddenly thrown in that direction? Indeed, would not the movement to the left, by drawing the enemy's attention in that direction, facilitate that result?

JOHN A. McClernand.

IN THE FIELD, five-Mile Creek, May 11, 1863.

Lieutenant Colonel John A. RAWLINS,

Assistant Adjutant-GENERAL:

COLONEL; The cavalry sent out this morning to reconnoiter on the roads leading to Edwards Station and to Raymond, have returned. The party going to Edwards Station found the enemy within half a mile of Fourteen-Mile Creek in too strong force to allow the party to proceed farther. Negroes informed the officer in command that the enemy intended to offer obstinate resistance at that creek. Still, I do not think he is in strong force there.

You heard this morning the result of the reconnaissance on the Raymond road. Our party fell in with the enemy's pickets, who ran. There is little or no water between here and Fourteen-Mile Creek; so we will probably have to fight for the water of that stream.

I think of sending General Smith's DIVISION from Cayuga to Baldwin's Ferry, and from there to the right, on the road leading from Baldwin's Ferry to New Auburn, until his right forms a junction with the left of the balance of the corps, instructing him to leave such a force to guard Baldwin's Ferry as the may think expedient. Cavalry only can reach Baldwin's to-night, and I have only one company to send, the balance behind down out for the present.

Your obedient servant,

JOHN A. McClernand.