TRUE!
During the historic earthquakes, the force of the land upheaval 15 miles south of New Madrid turned the river against itself to flow backward. The Mississippi River flowed backward for 10 to 24 hours. The uplifted land created two temporary waterfalls on the river. The new cliffs were soon eroded as the river returned to the normal direction. Boatman on flatboats survived this experience and lived to give first hand accounts of the river running backward!