RICHARDSON'S ATTACK. While French was thus dealing with General D. H. Hill, Richardson was engaging Longstreet. Richardson crossed the Antietam about ten o'clock. He marched down the western bank, across the farm of Mr. Newkirch, crossing the little stream coming down from Rulet's. He moved to gain the high knolls between Rulet's and the Boonesboro' road. Having crossed the brook, he faced west, drove in the Rebel pickets, and ascended the nearest knoll. All of Longstreet's batteries opened upon him, but his men moved round the hillock, through the hollows, and marched well up to the Rebel lines with little loss. General Meagher, with his Irish brigade, was on the right, the tip of its wing touching Rulet's garden. Caldwell's brigade was on the left, reaching down nearly to the Boonesboro' turnpike. Brooks's brigade was in reserve. Longstreet's batteries were on the hills around Dr. Piper's, and his troops a part of them in the pathway, the upper end of which was held by D. H. Hill. His line was so formed, and such was the ground, that Caldwell, instead of swinging round upon Sharpsburg, was obliged to fall in rear of Meagher, and become a second line, instead of a part of the first. It was eleven o'clock when Richardson moved forward. French was pouring in his volleys north of Rulet's, and now Meagher, climbing the knolls, and rushing up the ravines, came upon the Rebels in the road. It was a repetition, or rather a continuation, of the terrible scene then enacting a few rods further north,--hundreds falling at every discharge. The courage of the Irish brigade did not flag for an instant. They fought till their ammunition was exhausted. They drove the Rebels from the road and held it. Again and again Longstreet endeavored to recover it, but could not succeed. General Richardson was wounded and carried from the field. General Meagher was bruised by the falling of his horse. His men worn, exhausted, half their number killed and wounded, were withdrawn. He retired by breaking ranks and filing to the rear, Caldwell's troops filing to the front at the same moment and taking their places. It was done as deliberately as a dress parade. The ground towards the Boonesboro' pike is very much broken. There are numerous hillocks and ravines, cornfields, stone walls, and fences. Under shelter of these, Longstreet stealthily moved a division to attack Caldwell's right flank in the cornfield west of the sunken road. It was a part of the force attacking French. Brooks's brigade went upon the run up the ravine, and filled the gap between Caldwell and Kimball, and held it against all the assaults of the enemy.