The flanking of the Southern army was a complete and overwhelming surprise. Johnston, unacquainted with the ground, had yielded the execution of the battle to his subordinate. While the two puzzled generals were waiting on their hill top for their orders of battle to be developed on the right they looked to the left and the whole valley was a boiling hell of smoke and dust and flame. Their left flank had been turned and the triumphant enemy was rolling their long line up in a shroud of flame and death. The two Generals put spurs to their horses and dashed to the scene of action, sending their couriers flying to countermand their first orders. They reached the scene at the moment Bee's and Evans' shattered lines were taking refuge in a wooded ravine and Jackson had moved his men into a position to breast the shock of the enemy's avalanche. In his excitement Johnston seized the colors of the fourth Alabama regiment and offered to lead them in a charge. Beauregard leaped from his horse, faced the troops and shouted: "I have come to die with you!" The first of the reserves were rushing to the front in a desperate effort to save the day. But in spite of the presence of the two Commanding Generals, in spite of the living stone wall Jackson had thrown in the path of the Union hosts, a large part of the crushed left wing could not be stopped and in mad panic broke for the rear toward Manassas Junction. The fate of the Southern army hung on the problem of holding the hill behind Jackson's brigade. On its bloody slopes his men crouched with rifles leveled and from them poured a steady flame into the ranks of the charging Union columns. Beauregard led the right wing of his newly formed battle line and Jackson the center in a desperate charge. The Union ranks were pierced and driven, only to re-form instantly and hurl their assailants back to their former position. Charge and counter-charge followed in rapid and terrible succession. The Confederates were being slowly overwhelmed. The combined Union divisions now consisted of an enveloping battle line of twenty thousand infantry, seven companies of cavalry and twenty-four pieces of artillery, while behind them yet hung ten thousand reserves eager to rush into action. Beauregard's combined forces defending the hill were scarcely seven thousand men. At two o'clock the desperate Southern commander succeeded in bringing up additional regiments from his right wing. Two brigades at last were thrown into the storm center and a shout rose from the hard-pressed Confederates. Again they charged, drove the Union hosts back and captured a battery of artillery. The hill was saved and the enemy driven across the turnpike into the woods. McDowell now hurried in a division of his reserves and re-formed his battle line for the final grand assault. Once more he demonstrated his skill by throwing his right wing into a wide circling movement to envelop the Confederate position on its left flank.