McDowell, in the meantime, all unconscious of what has transpired in the
Shenandoah Valley, and between there and Manassas; never dreaming for an
instant that Patterson has failed to keep Johnson there--even if he has
not attacked and defeated him; utterly unsuspicious that his own
lessened Union Army has now to deal with the Forces of Johnston and
Beauregard combined--with a superior instead of an inferior force; is
executing a plan of battle which he has decided upon, and announced to
his general officers, on that same Saturday evening, at his Headquarters
in Centreville.

Instead of attempting to turn the Enemy's right, and cut off his
communications with Richmond and the South, McDowell has now determined
to attack the Enemy's left, cut his communication, via the Manassas Gap
railroad, with Johnston's Army,--still supposed by him to be in the
Valley of the Shenandoah--and, taking him in the left flank and rear,
roll him upon Manassas, in disorder and defeat--with whatever might
follow.

That is the plan--in its general features. In executing it, Blenker's
Brigade of Miles's Division is to remain at Centreville as a reserve,
throwing up intrenchments about its Heights, upon which to fall back, in
case of necessity; Davies's Brigade of the same Division, with
Richardson's Brigade of Tyler's Division--as the Left Wing--are to
demonstrate at Blackburn's Ford, toward the Enemy's right; Tyler's other
three brigades, under Keyes, Schenck, and Sherman, are to feign an
attack on the Enemy's left, posted behind the strongly-defended Stone
Bridge over which the Warrenton turnpike, running Westward, on its way
from Centreville to Warrenton, crosses Bull Run stream; while the strong
divisions under Hunter and Heintzelman--forming McDowell's Right Wing