All were to clear off the parapets and the _abatis_ in their front so as to leave the space as open as possible, and be able to charge the moment the mine had been sprung and Burnside had taken possession.

Burnside's corps was not to stop in the crater at all but push on to the top of the hill, supported on the right and left by Ord's and Warren's corps.
Warren and Ord fulfilled their instructions perfectly so far as making ready was concerned.

Burnside seemed to have paid no attention whatever to the instructions, and left all the obstruction in his own front for his troops to get over in the best way they could.

The four divisions of his corps were commanded by Generals Potter, Willcox, Ledlie and Ferrero.

The last was a colored division; and Burnside selected it to make the assault.