Tyler placed Schenck's brigade on the left of the turnpike, in a position that menaced the Confederate battery at the Stone Bridge, and Sherman's was posted on the right, to be in a position to sustain Schenck or to cross Bull's Run, as circumstances might require. When this disposition was made, a shell was hurled from a 30-pounder Parrott gun of Edwards's Fifth Artillery battery (then attached to Carlisle's, and stationed in the road, under the direction of Lieutenant Haines) at a line of Confederate infantry seen in a meadow beyond Bull's Run. This was the herald of the fierce battle on that eventful day. It exploded over the heads of the Confederates, and scattered their ranks. Other shells were sent in quick succession, but elicited no reply. This silence made McDowell suspect that the Confederates were concentrating their forces at some point below, to strike his left wing. He therefore held one of Heintzelman's brigades (Howard's) in reserve for a while, to assist Miles and Richardson if it should be necessary.
Colonel Evans, commanding at the Stone Bridge, believing Tyler's feint to be a real attack, sent word to Beauregard that the left wing of their army was strongly assailed. Re-enforcements were ordered forward, and Cocke and Evans were instructed to hold the position at the bridge at all hazards, At the same time, hoping to recall the troops in front of Evans, Johnston ordered an immediate, quick, and vigorous attack upon McDowell's left at Centreville; and his force was so strong on his right, that he and Beauregard confidently expected to achieve a complete victory before noon. The movement miscarried, as Ewell soon informed them; and crowding events changed their plans. From an eminence about a mile from Mitchell's Ford, the two commanders watched the general movements, and waited for tidings of the battle that soon began, with the greatest anxiety. A cloud of dust, seen some distance to the northward, gave Johnston apprehensions that Patterson was approaching, not doubting that he had hastened to re-enforce McDowell as soon as he discovered that the Army of the Shenandoah had eluded him.
Before we consider the conflict, let us take a glance at the topography of the region about to become a sanguinary battle-field:--
Near the Stone Bridge the general course of Bull's Run is north and south, and the Warrenton turnpike crossed it there nearly due west from Centreville. On the western side of the Run the road traversed a low wooded bottom for half a mile, and then, passing over a gentle hill, crossed, in a hollow beyond, a brook known as Young's Branch. Following the little valley of this brook, the road went up an easy slope to a plain in the direction of Groveton, about two miles from the Stone Bridge, where a road from Sudley's Spring crossed it. Between that road and the Stone Bridge, Young's Branch, bending northward of the turnpike, forms a curve, from
