...antry as a corps of observation and to check flanking movements; or, if possible, to decoy the enemy down the Pamunkey. At about noon a powerful corps of the enemy, consisting of Gen. A. P. Hill's, D. H. Hill 's, Longstreet's, and Anderson's divisions--then supposed to be Jackson's force--under command of Major-General Robert E. Lee, crossed the river at Mechanicsville bridge, Meadow bridge, and at Atlee's...