of the Shenandoah,
wedged apart by the long and narrow range, or rather ranges, known
as the Massanutten, unite near Front Royal, where the valley begins
to widen to a plain, and pour their waters into the Potomac at
Harper's Ferry. Of the two valleys thus formed, the easternmost,
through which runs the South Fork, takes the name of Luray, or, in
local usage, Page, from its chief county, while the more western
and more important, in the lap of which lies the North Fork,
preserves the name of Shenandoah, as well for the river as the
county. Through this valley lies the course of the great macadamized
highway that before the days of steam formed the chief avenue of
communication between Pennsylvania and Virginia. Soon after the
valley begins to widen, beyond Strasburg and Front Royal, the
Opequon takes its rise in the western range, here known as Little
North Mountain, and, flowing northeast, falls into the Potomac
below Williamsport. The Cumberland valley continues the valley of
Virginia into Pennsylvania, the two being separated by the Potomac,
which in this part of its course is usually fordable at many points.
Topography was by no means Grant's strong suit, yet he was not long
in perceiving that the southwesterly trend of this great valley
led and must always lead an invading column at every step farther
away, not only from its base on the Potomac, but practically also
from its objective at Richmond. Wherefore this zone was useless
to the armies of the Union, while for the Confederates it had the
triple advantage of a granary, an easy and secure way into Maryland
and Pennsylvania, and on the flank toward Washington a mountain
wall, cut by numerous gaps, of equal convenience in advance or
retreat, besides being a constant menace to Washington as well as
to the Union army operating between the Blue Ridge and the Potomac.
Thus it was that the Confederate force was able to move speedily
and unobserved to the north bank of the Potomac at Williamsport,
and there, ninety miles north of Washington, equally distant from
Baltimore and from Washington, and actually nearer to the Susquehanna
than the capital is, held the whole country at its mercy until the
Army of the Potomac could be hurried to the rescue.

Grant's first orders to Sheridan were twofold: he was to move
south by the valley, no matter where Early might be, or what he
might be doing, in full confidence that Early would surely be found
in his front; and he w