This photograph of May 30, 1864, shows the Federal cavalry in actual
operation of a most important function--the "screening" of the army's
movements. The troopers are guarding the evacuation of Port Royal on the
Rappahannock, May 30, 1864. After the reverse to the Union arms at
Spottsylvania, Grant ordered the change of base from the Rappahannock to
McClellan's former starting-point, White House on the Pamunkey. The
control of the waterways, combined with Sheridan's efficient use of the
cavalry, made this an easy matter. Torbert's division encountered Gordon's
brigade of Confederate cavalry at Hanovertown and drove it in the
direction of Hanover Court House. Gregg's division moved up to this line;
Russell's division of infantry encamped near the river-crossing in
support, and behind the mask thus formed the Army of the Potomac crossed
the Pamunkey on May 28th unimpeded. Gregg was then ordered to reconnoiter
towards Mechanicsville, and after a severe fight at Hawes' shop he
succeeded (with the assistance of Custer's brigade) in driving Hampton's
and Fitzhugh Lee's cavalry divisions and Butler's brigade from the field.
Although the battle took place immediately in front of the Federal
infantry, General Meade declined to put the latter into action, and the
battle was won by the cavalry alone. It was not to be the last time.