It will be seen from this order of march that, in proportion as they went forward, Buford's cavalry, with the three infantry corps forming the left wing, were approaching the enemy's main body at Chambersburg. South Mountain was, therefore, the wall behind which the two contending armies were playing at hide-and-seek.[26]
Lee hears Meade is coming.
Lee had only just given orders for his whole force to move on Harrisburg, when, late in the night of the 28th, a scout brought news to him of the Union army being across the Potomac, and on the march toward South Mountain.[27] This report could not fail to throw the Confederate headquarters into a fever of excitement, ignorant to that hour of that army's being across the Potomac. The mystery was cleared up at last. In a moment the plan of campaign was changed.[28] Lee soon said to some of the officers about him, "To-morrow, gentlemen, we will not move to Harrisburg as we expected, but will go over to Gettysburg and see what General Meade is about."
March on Gettysburg begun.
By placing himself on the direct road to Baltimore, Lee's purpose of first drawing the Union army away from his line of retreat, and of then assailing it on its own, stands fully revealed. The previous orders were therefore countermanded on the spot. Hill and Longstreet were ordered from Chambersburg to Gettysburg,[29] Ewell was called back from Carlisle, and Early from York.
Faulty Tactics.
If Meade had known Lee's whereabouts, it is safe to assume that the Union army would have been massed toward its left rather than its right; and if Lee had been correctly informed on his part, it is unlikely that he would have risked throwing his columns out at random against the Union army, as he was now doing. Only the fatuity of the Union generals saved Lee's vanguard on the 1st of July. Yet he held the very important advantage of having already begun the concentration of his army—an easy thing for him to do, inasmuch as but one of his three corps was separated from the others—before Meade discovered by chance what was so near proving his ruin. One day's march would bring all three up within supporting distances, two in position for giving battle.
Confederate Positions June 29th.
Heth's division of Hill's Corps got as far as Cashtown, eight miles from Gettysburg, on the 29th; Rodes' division of Ewell's Corps was coming down by the direct road from Carlisle, east of South Mountain; Early's division of this corps began its march back from York to Gettysburg on the morning of the 30th. These three divisions, or one-third of Lee's whole army, therefore, formed the enemy's vanguard which would first strike an approaching force. But, as we have seen, the whole army was in march behind it, and by the next day well closed up on the advance.