...nd Fairfield routes, the army to march after night by the latter,--the Second Corps as rear-guard, the First to follow the Third and push on to secure the crossings of the Potomac at Williamsport and Falling Waters . It was daylight of the 5th when the road was open for the march of the First, and a later hour of the morning before the Second could follow. Pursuit was made by the enemy, led by cavalry an...