From Robert E. Lee by Douglas Southall Freeman (Vol. III, Chapter XVI, Page 278).
"For two miles, through the scrub growth of the Wilderness, Lee rode on ahead of Heth's division, with no enemy in sight. Shortly before 3 o'clock, he turned aside into a little clearing on the left-hand side of the road. Riding to a grove of trees in an elevated field, whence there was a view down the valley of Wilderness Run, he dismounted with Hill and Stuart to study the ground while awaiting the arrival of the leading division. Nearby was the home of the Widow Tapp, destined ere two days were done, to become a sinister name in American military history.
Lee was concerned at the separation of the two corps, which apparently he had not anticipated. With Ewell seriously engaged, and the enemy in close proximity to Hill's front, there was manifest danger that Grant would find the gap between Hill's left and Ewell's right. The Federals might then pour into the unguarded area and perhaps might turn the exposed flanks of both corps. As if to confirm this fear, a blue skirmish line deployed in a few minutes from the cover of some old-field pines within easy musket range on the left. Hill remained where he was, either from surprise or in the belief that the skirmishers would fall back. Stuart stood up. Lee, rising quickly, hurried off, calling loudly for Colonel Taylor, in order, doubtless, to give instructions for troops to be advanced to drive back the Unionists. Had the Federals pressed on, they might have made the richest capture that had fallen to any soldiers in the war, but they were as surprised at meeting graycoats as the Confederates were at seeing them, and they quickly withdrew without firing a shot. The direction of their advance was ominous, nevertheless. Doubtless other forces were behind them in the gap between Hill and Ewell. As quickly as he could reach him, Lee ordered Wilcox, who was behind Heth, to file off to the left and to establish contact with the right of Ewell's corps."