Simply because they're truly awesome, here are two more maps from Harold N. Fisk's 1944 Report. I'm a huge fan.
One wonders if the Army Corps of Engineers will ever learn that treating rigidity and permanence as design orthodoxy in a landscape where instability and suppleness are supreme can only lead to catastrophic consequences, no matter how much federal money are pumped into their projects. Perhaps they have, but I see little evidence of this. And to think that India and Bangladesh, in their attempts to control the Ganges and Brahmaputra, are looking to the corps for ideas and models.
Lower Mississippi Valley - Engineering Geology Mapping Program