Well, regardless of whose idea it initially was to move the cavalry to Crystal Springs, Grant ultimately told him to do it beforehand, so the onus would be on Grant not McPherson.
Here are the relevant communications. McClernand writes Grant at 9 a.m. on the 10th, informing him that McClernand's men have reached 5 Mile Creek. Grant doesn't receive it until 4 pm. and responds. Grant then writes McPherson telling him McClernand's position and asking him to send the cavalry out to watch the southeast. McPherson writes back: oopsies, the cavalry already left.
Cayuga, Miss,, May 10, 1863. Maj. Gen. IJ. S. Grant, Comdg. Dept. of the Tennessee:
General : The head of my column is arrived at this place. Its advance guard is at Five-Mile Creek. Various rumors of the enemy's crossing detachments of cavalry and infantry over Big Black are afloat, but as yet are unauthenticated.
I beg to remind you again that my corps is supplied with a very small number of teams, and their cooking utensils in large part are behind. It is but just, both to you and myself, that this fact should be stated. Your most obedient servant,
JOHN A. McCLERNAND.
Cayuga, Miss., May 10, 1863—4 p. m. Maj. Gen. John A. McOlernand, Comdg. Thirteenth Army Corps:
Your note, written at 9 a. m., is just received. My headquarters will remain here to-night aud be removed to Auburn in the morning. You need not move to-morrow, except to better your position on Five-Mile Creek.
Sherman, whose rear will not be able to pass this place to-night, will move up so as to be about the same distance from the Vicksburg and Jackson Railroad as yourself. McPherson will also move on to about the same east and west line, starting from Utica.
Your note complains of want of transportation. I have passed one and a part of another of your divisions, and am satisfied that the transportation with them, to say nothing of the large number of mules mounted by soldiers, would carry the essential parts of five days' rations for the command to which they belong, if relieved of the knapsacks, officers, soldiers, and negroes now riding. You should take steps to make the means at hand available for bringing up the articles necessary for your corps. Equal facilities have been given each of the army corps in all respects, no special order having been given to favor any one, except to give the first 30 wagons to the Thirteenth Army Corps.
U. S. GRANT.
Cayuga, Miss., May 10, 1863.
Maj. Gen. J. B. McPherson, Comdg. Seventeenth Army Corps: General McOlernand is now on Five-Mile Creek, on the Telegraph road to Edwards Station. He is directed to move no farther to-morrow, but to reconnoiter the road to Fourteen-Mile Creek. Sherman will not get much past this place to-night. In the morning he will move forward to Auburn, and, if he meets with no resistance, will throw his advance forward to Fourteen-Mile Creek, on the Raymond road.
Move your command forward also, so as to occupy something near the same east and west line with the other army corps. Let me know what point you move to. Send your cavalry out to watch the enemy as far to the southeast as you can.
U. S. GRANT.
Headquarters Seventeenth Army Corps,
Weeks' Plantation, 4 miles east of Utica, May 10, 1863.
Maj. Gen. U. S. Grant,
Commanding Department of the Tennessee :
General : Inclosed please find a sketch of my position.* The road is very dry and dusty following the divide between Big Black and north fork of Bayou Pierre. There are no streams on the road, and the troops have suffered some for want of water.
On my arrival in Utica about noon, I found Colonel Wright, with his cavalry, who reported considerable skirmishing with the enemy, but as no one was hurt, the skirmishing amounted to very little. There were probably 100 rebel cavalry in our front, and a small force reported at the bridge across Tallahala Creek, north fork of Bayou Pierre, on the road to Crystal Springs. I immediately dispatched Colonel Wright, with his whole cavalry force, in a southeast direction, crossing the creek lower down than where this force was said to be stationed, and then to proceed up on the south side and cut them off, if possible. He was also instructed to learn all he could of the movements of the enemy, and as it is only 18 or 20 miles to the Mississippi Central Bailroad, and probably not many troops in that direction, to make a dash over that way, and destroy the telegraph and railroad track, if he should find it j)racticable.
A forward movement of about 5 miles will bring me on an east and wrest line with Auburn, and near one of the branches of Fourteen-Mile Creek.
I had to be guided to-day in selecting camps somewhat by the chances of getting water.
Very respectfully, your obedient servant,
JAS. B. MoPHERSON