in those times, waterways were the major highways of commerce. early developments along the east coast of the colonies tended to end at the fall line (the head of navigation) of the rivers that emptied into its great bays (e.g., the delaware and the chesapeake). such early communities in virginia included what we now know as alexandria on the potomac river, fredericksburg on the rappahannock river, richmond and lynchburg on the james river and petersburg on the appomattox river.