The Confederate infantry now pressed forward in a frenzy of enthusiasm. The piercing "rebel yell" rose triumphantly above the roar of cannon and the bark of musketry, and many regiments pressed clear to the borders of the cedars in which the Union troops were posted, before they had to retire from a merciless fire. Again and again Hardee and Cheatham brought their men to the charge. The exigencies of the battle twisted the Union line into strange shapes. Here a brigade was in a half-circle with a concave side to the enemy; another presented a convex front to attack. Miller's brigade of Negley's division was like a triangle without the base, and, aided by splendid artillery service, repulsed simultaneously assaults in front and on both sides. But many trains having been captured or swept away, Sheridan's men found themselves out of ammunition, and his division was withdrawn, leaving Negley's right and Rosseau's left "in the air." Into the interval poured the Confederate columns. Thomas was compelled to withdraw his two divisions to an improvised line, and Negley and Rosseau reluctantly faced the rear. The firing had been so heavy in these divisions that the cartridge-boxes of dead and wounded had been robbed for the precious ammunition. Rosseau made the movement under fire, but, reaching Thomas's temporary line, turned and delivered such a blast from rifles and artillery as threw back the pursuing enemy and left the field covered with bodies. Shepherd's brigade of regulars especially distinguished itself here; for, firing by platoon from flank to flank,--as steadily as though at drill,--it cut down the enemy in front as a scythe mows grain, and drove away a greatly superior force, losing in a few minutes one-third of its whole number. Negley's division was almost surrounded, and had to cut its way,--sometimes at the point of the bayonet,--through the Confederates, who had reached its rear. In the movement this division had to abandon six guns. Palmer's division, which was already fiercely engaged, was now in the greatest peril, as Negley's retirement left an unprotected flank. On the right Cruft's brigade was almost surrounded while repulsing a frontal attack; but Grose's brigade, held in reserve, changed front to the rear and cleared a way. Hazen, at the apex of what was known as the "Round Forest," met repeated heavy attacks, but, owing to superior position and artillery support, was able to hold his own, though losing heavily. As Palmer retired, his division established connection with the right and faced the enemy with renewed confidence.