Cavalry was useless.

One battalion of Illinois cavalry was strongly suspected of camping in the timber, until time passed enough to justify the suspicion of having been somewhere.

Really the strength of Vicksburg was in being out of reach of attack....
"My orders were to learn and report what was going on on the right, particularly to try and form an idea of the enemy's force in front of M.L.Smith's division, and at the sand-bar.

Leaving my horse close in the rear of the Sixth Missouri, when the fire became too heavy for riding, I succeeded, by taking frequent cover, in reaching unhurt the verge of the bayou among the drift-logs.
There, by concert of action with Lieutenant-Colonel Blood, of the Sixth Missouri, his regiment, and the Thirteenth Regular Infantry, kept up a heavy fire on everything that showed along the levee and earthworks in front.

The enemy were behind the embankment, not over one hundred and fifty yards across the bayou.