...land Valley from the undulating plain which lies between the Potomac on the south, the Susquehanna on the north, and Chesapeake Bay on the east. It was by the Cumberland Valley that Lee penetrated Pennsylvania : he had gone out of it to march on Gettysburg; he returned to it to resume the road to Virginia. Besides the railroad which from Harrisburg and Carlisle is extended through Chambersburg and Greenca...