Note:  Do not rely on this information. It is very old.


Delta, so named from the resemblance in form of that of the Nile to the triangular Greek capital letter D, A, is a tract of flat land of alluvial origin, formed by the advance of the fan-like cones of sediment carried down by a river into a lake or the sea. These accumulations cause the stream to subdivide repeatedly, so that the triangular plain with its apex pointing up-stream is traversed by innumerable tortuous water-channels. These are constantly silting up, while new ones are cut through the soft earth. The delta of the Nile is the whole of Lower Egypt below Cairo; that of the Rhine includes all Holland: the Rhone has two deltas, one at the head of the Lake of Geneva and the other below Avignon: the delta of the Tiber advances 10 feet annually; and that of the Mississippi, covering 40,000 square miles, gains 86 yards a year.