ass on the Blue Ridge by detachments as we approached it, and
guarding them after we had passed, as long as they would enable the
enemy to trouble our communications with the Potomac.... We depended
upon Harper's Ferry and Berlin for supplies until the Manassas Gap
Railway was reached. When that occurred, the passes in our rear were
to be abandoned, and the army massed ready for action or movement in
any direction. It was my intention, if, upon reaching Ashby's or any
other pass, the enemy were in force between it and the Potomac, in the
Valley of the Shenandoah, to move into the Valley and endeavor to gain
their rear."

From this statement of General McClellan it will be seen that his plan
was judicious, and displayed a thorough knowledge of the country in
which he was about to operate. The conformation of the region is
peculiar. The Valley of the Shenandoah, in which Lee's army lay
waiting, is separated from "Piedmont Virginia," through which General
McClellan was about to advance, by the wooded ramparts of the Blue
Ridge Mountains, passable only at certain points. These _gaps_, as
they are called in Virginia, are the natural doorways to the Valley;
and as long as General McClellan held them, as he proposed to do,
by strong detachments, he would be able both to protect his own
communications with the Potomac, and, if he thought fit to do so,
enter the Valley and assail the Confederate rear. That he ever
seriously contemplated the latter design is, however, extremely
doubtful. It is not credible that he would have undertaken to "cut
off" Lee's whole army; and, if he designed a movement of that
description against any portion of the Southern army which might be
detached, the opportunity was certainly presented to him by Lee, when
Jackson was left, as will be seen, at Millwood.

No sooner had General McClellan commenced crossing the Potomac, east
of the mountain, than General Lee broke up his camp along the Opequan,
and moved to check this new and formidable advance into the heart of
Virginia. It was not known, however, whether the whole of the Federal
forces had crossed east of the Blue Ridge; and, to guard against a
possible movement on his rear from the direction of Harper's Ferry,
as well as on his flank through the gaps of the mountain, Lee sent
Jackson's corps to take position on the road from Charlestown to
Berryville, where he could oppose an advance of the enemy from either
direction. The rest of the army then