About the close of this battle, Brevet Major-General Charles Griffin relieved Major-General Warren in command of the 5th corps.  The report of this reached me after nightfall.  Some apprehensions filled my mind lest the enemy might desert his lines during the night, and by falling upon General Sheridan before assistance could reach him, drive him from his position and open the way for retreat.  To guard against this, General Miles’s division of Humphreys’s corps was sent to reinforce him, and a bombardment was commenced and kept up until four o’clock in the morning (April 2), when an assault was ordered on the enemy’s lines.  General Wright penetrated the lines with his whole corps, sweeping everything before him, and to his left towards Hatcher’s Run, capturing many guns and several thousand prisoners.  He was closely followed by two divisions of General Ord’s command, until he met the other division of General Ord’s that had succeeded in forcing the enemy’s lines near Hatcher’s Run.  Generals Wright and Ord immediately swung to the right, and closed all of the enemy on that side of them in Petersburg, while General Humphreys pushed forward with two divisions and joined General Wright on the left.  General Parke succeeded in carrying the enemy’s main line, capturing guns and prisoners, but was unable to carry his inner line.  General Sheridan being advised of the condition of affairs, returned General Miles to his proper command.  On reaching the enemy’s lines immediately surrounding Petersburg, a portion of General Gibbon’s corps, by a most gallant charge, captured two strong inclosed works—­the most salient and commanding south of Petersburg—­thus materially shortening the line of investment necessary for taking in the city.  The enemy south of Hatcher’s Run retreated westward to Sutherland’s Station, where they were overtaken by Miles’s division.  A severe engagement ensued, and lasted until both his right and left flanks were threatened by the approach of General Sheridan, who was moving from Ford’s Station towards Petersburg, and a division sent by General Meade from the front of Petersburg, when he broke in the utmost confusion, leaving in our hands his guns and many prisoners.  This force retreated by the main road along the Appomattox River.  During the night of the 2d the enemy evacuated Petersburg and Richmond, and retreated towards Danville.  On the morning of the 3d pursuit was commenced.  General Sheridan pushed for the Danville Road, keeping near the Appomattox, followed by General Meade with the 2d and 6th corps, while General Ord moved for Burkesville, along the South Side Road; the 9th corps stretched along that road behind him.  On the 4th, General Sheridan struck the Danville Road near Jetersville, where he learned that Lee was at Amelia Court House.  He immediately intrenched himself and awaited the arrival of General Meade, who reached there the next day.  General Ord reached Burkesville on the evening of the 5th.