...s of pickets, from the fords of the Upper Rappahannock, twenty-five miles above our position, to Port Royal, twenty-five miles below. They had also busily filled up the interval since the battle of Fredericksburgh , in fortifying every point available for crossing, by throwing up earth-works and digging rifle-pits. Their experience at Fredericksburgh had taught them all the use of these powerful auxiliaries...