Anyway, this author also wrote "Dirt - the Erosion of Civilization", a very interesting look at how the role of soil management in the development and decline in societies. I highly recommend it.
Our family visited the are when I was a kid back in the early 60s. Even then it was widely accepted that it was formed by a flood. I remember at the dry falls that they estimated more water flowed over it than two Niagra falls.