Creek. This rendered that position untenable. I therefore determined still further to concentrate the army, by withdrawing Porter's command to a position near Gaines' Mill, where he could rest both his flanks on the Chickahominy and cover the most important bridges over that stream. The wagons and heavy guns were withdrawn during the night, the troops falling back to their new position early in the morning. The enemy attacked Seymour's brigade, constituting the rear guard of the division, McCall's, but were sharply repulsed, and the movement was not further molested.

In the course of the morning of the 27th I received intelligence that Longstreet's corps was at Mechanicsville, ready to move down on either bank of the Chickahominy, according to circumstances. This intelligence, and many threatening movements of the enemy on various parts of the center and left, placed a limit to the amount of the re-enforcements available for the support of Porter. Under the circumstances, it was impossible to withdraw him to the right bank of the Chickahominy by daylight. The enemy were so close upon him that the attempt would have insured the loss of a large portion of his corps, and in any event the abandonment of his position at that time would have placed our right flank and rear at the mercy of the enemy. It was necessary to fight him where we stood, to hold our position at any cost until night, and in the mean time to perfect the arrangements for the change of base to the James River.

In the report of General Porter will be found a detailed description of the field of battle at Gaines' Mill and the circumstances of that eventful contest, creditable alike to the energy of the enemy and the desperate valor of the comparatively small band that repelled the attacks of his enormous masses.

It will suffice for the purpose of this report to state that the action commenced about 3 p.m., and that during the afternoon I ordered up the division of Slocum to the support of Porter, and soon after the brigades of French and Meagher, of Richardson's division. The latter were not engaged. At a later period two brigades of Peck's division were ordered forward, but as their services were not needed they did not cross the Chickahominy. The contest continued with varying of fortunes until dark, when the enemy discontinued his attack. During the night the final withdrawal of the right wing across the Chickahominy was completed without difficulty and without confusion, a portion of the regulars remaining on the left bank until the morning of the 28th. Early on the morning the bridges were burned, and the whole army was thus concentrated on the right bank of the Chickahominy.

During the battle of Gaines' Mill the position of General Smith was warmly attacked, but the enemy was at once repulsed with loss. In the course of the night of the 17th General Keyes was ordered to cross the White Oak Swamp with the Fourth Corps and take up a position to cover the passage of the trains. Measures were also taken to increase the number of bridges across the swamp. The trains were st in motion at an early hour, and continued passing across the swamp night and day without intermission until all had crossed.

On the 28th Porter's corps was also moved across the White Oak Swamp, and on the morning of the 29th took up a position covering the roads leading from Richmond toward the White Oak Swamp and Long Bridges.

During the night of the 28th and 29th the division of Slocum and McCall were ordered across the White Oak Swamp, and were placed in