"The bed of the river is so broad that the channel meanders from side to side within the bed, just as the bed itself meanders from bluff to bluff; and, as by erosions and deposits, the river, in long periods of time, traverses the valley, so the channel traverses the bed from bank to bank, justifying the remark often heard, that 'not a square rod of the bed could be pointed out that had not, at some time, been covered by the track of steamboats.'"—J.H. SIMPSON, Col. Eng., Brevet Brig.-Gen., U.S.A.
One of the most noteworthy examples of these cut-offs is Davis'. This cut-off occurred at Palmyra Bend, eighteen miles below Vicksburg. The mid-channel distance around the bend was not far from twenty miles; the neck was only twelve hundred feet across. The fall of the river, measured around the bend, was about four inches per mile; the slope, measured across the neck, was about five and one-half feet, nearly twenty feet per mile. Inasmuch as the soil in the neck was wholly alluvial, the current cut its new channel with exceedingly great rapidity, soon clearing it out a mile in width and more than one hundred feet in depth. The water rushed through the channel with such a velocity that steamboats could not breast its flow for many weeks, while the roaring of its flood could be heard many miles away. The influence of the cut-off was felt both above and below Vicksburg for several years after. The rate of erosion has been perceptibly increased above Vicksburg: and it is not unlikely that the cut-off which occurred a few years later at Commerce, about thirty miles below Memphis, was a result of Davis' Cut. Other recent cut-offs have occurred near Arkansas City, below Greenville, near Duncansby, below Lake Providence at Vicksburg, and at Kienstra. The latter place is below Natchez; all the others are between Natchez and Memphis. A double cut-off is strongly threatened at Greenville.
For convenience to navigation, the islands in the lower Mississippi, beginning at St. Louis, are numbered. Many of them, however, have local names by which they are frequently known.