A fall line is an imaginary line that lies between the two parallel rivers at a point where the waterfalls. From the same height that is represented by a fall line.
Formed at the upland and the coastal plain region. Where the river has eroded away the soft rocks more easily than those of the upland region.
For a map of the mountainous area, the elevation has to be 5-100 meters. As the area is a mountain or a hilly upland area, it has a contour interval of 100 meters or more. For a relatively flat area it as to have a C.I of 10 meters or less.
