That Lee could not long remain on Seminary Ridge, let his position be ever so strong, was a self-evident proposition. He had exhausted his means of attack, his army was cut down by more than twenty thousand men, his ammunition was nearly expended, nor could it be replenished short of Virginia. His means of defence were therefore extremely limited. If it had been possible to detain Lee where he was, even for a few days longer, his surrender was a foregone conclusion without firing another shot. But taking the situation as we find it, we do not see how he could have been more critically placed, if in the presence of an enterprising opponent. Lee's attitude after the battle savors far more of bravado than a desire to be attacked. To block his retreat it would have been necessary to seize the Monterey Pass immediately after the battle.[77] Meade had the shorter line. His cavalry would have kept Lee at bay until the infantry could come up. He should never have suffered Lee to put South Mountain between them without making an energetic effort to prevent it. As the Union army remained immovable until this was done, we have only to chronicle in brief the inglorious ending of an otherwise glorious campaign. [Sidenote: Read over Chap. I.] All the 4th the two armies lay in the positions just now described. Lee's direct line of retreat to the Potomac was by the Fairfield and Hagerstown road, which crossed the mountain below and behind him through the Monterey defile. To withdraw his army and trains by this one road was altogether impracticable. The trains and wounded were therefore started off during the afternoon of the 4th, in a drenching rain, by the Chambersburg road, under a strong escort of cavalry and artillery, but no infantry.[78] When stretched out on the road this train was seventeen miles long. [Sidenote: Lee's Wounded.] Being ordered to push on to the Potomac without halting, the sufferings of the wounded were horrible beyond description. Travelling all night and avoiding Chambersburg, this column struck across the country to Greencastle, and after fighting its way all day against detachments of Union cavalry, finally got to the Potomac at Williamsport, on the afternoon of the 5th, with the loss of a few wagons. After the escort had passed through Greencastle, the citizens turned out and attacked the wagons in the rear with axes, so disabling some and delaying the rest. When the wagon train got there, the Potomac was found too high to be forded. The bridges were gone, and the trains could not get across that way.[79] So there Lee met his first check. After giving his trains a twelve hours' start, Lee put his army in motion for the Potomac by way of Fairfield and Hagerstown, by daylight of the 5th. [Sidenote: Lee's Infantry move off.] [Sidenote: A Lame Pursuit.]