Boonsborough Gap, Md., September 14, and Sharpsburg, Md., September 16 and 17:

On August 22, agreeably to orders of the commanding general, I proceeded to Freeman's Ford to relieve General Trimble's brigade. On my arrival in the afternoon I found the enemy had crossed over the river and were in the immediate front of General Trimble. The Texas brigade being placed on the right and Colonel Law's on the left, the attack was made at once, General Trimble leading off in the center. The enemy were driven precipitately over the Rappahannock with considerable loss, not less, I think, than from 200 to 300. During engagement Major D. M. Whaley, Fifth Texas, fell gallantly discharging his duties.

The next night the command marched to Waterloo Ford and relieved General A. P. Hill's division. From this point, having joined the main body of General Longstreet's forces, the march was continued in the direction of Manassas. On arriving at Thoroughfare Gap the enemy were drawn up in line do dispute our passage. After a spirited little engagement with them by General D. R. Jones' troops, on the evening of the 28th instant, our forces were able to bivouac for the night beyond the Gap.

The next morning at daylight the march was again resumed, with the plains of Manassas, engaging General Jackson's forces. Disposition of the troops being made, the Texas brigade advanced in line of battle down and on the immediate right of the pike leading to the stone bridge, and Colonel Law's brigade on the left. Arriving on a line with the line of battle established by General Jackson, the division was halted by order of the general commanding.

About 4 o'clock in the afternoon the enemy made a fierce attack upon General Jackson, his noble troops holding their ground with their usual gallantry. At sunset an order came to me from the commanding general to move forward and attack the enemy. Before, however, this division could come to attention it was attacked, and I instantly ordered the two brigades to move forward and charged, and I instantly ordered the two brigades to move forward and charge the enemy, which they did most gallantly, driving them in confusion in front of them. Colonel Law's brigade, being engaged with a very heavy force of the enemy, captured one piece of artillery, three stand of colors, and 100 prisoners, and the Texas brigade three stand of colors. It soon became so very dark that it was impossible to pursue the enemy any farther.

At 12 o'clock at night orders came to retake our position on the right of General Jackson, in which the battle of the plains of Manassas commenced by a most vigorous attack by the enemy upon the right of General Jackson. After a severe struggle the enemy gave way in great contusion on the left of the pike, and by direction of the general commanding I moved forward this division, with the Texas brigade on the right of the pike and Colonel Law's advancing on the left and passing over to the right. Within 150 yards after leaving their position the Texas brigade became engaged with a heavy force of the enemy, but with their usual daring and enthusiasm they charged gallantly on,