Five million years ago, the same geological forces that created the Rocky Mountains also raised part of the broad MidAmerican plain. The White river, which now flows miles away from the park, eroded the rock and volcanic ash that make up the plain, carving over eons a cliff.
Even now the exposed face of the upper plain, called the Wall, continues to erode about one inch per year. Of varying height, the Wall is a hundred miles of broken surface that exposes layer on geological layer of soil and rock and compacted volcanic ash, each layer three or four feet high and marked by distinct color changes.
That is the geology.
The phenomenology is harder to explain.
We never knew the wasteland would be beautiful.
