White River Badlands 43i. Keya Paha Tablelands 43j. Moreau Prairie 43k. It is a semiarid rolling plain of shale, siltstone, and sandstone punctuated by occasional buttes and badlands. Native grasslands persist in areas of steep or broken topography, but they have been largely replaced by spring wheat and alfalfa over most of the ecoregion.
Agriculture is limited by erratic precipitation patterns and limited opportunities for irrigation.
Sedimentary rocks that contain lignite coal underlie much of ecoregion 43a. Lignite within 100 feet of the surface is recoverable by strip mining. The topography of this ecoregion was largely unaffected by glaciation and retains its original soils and complex stream drainage pattern. A mosaic of spring wheat, alfalfa, and grazing land covers the shortgrass prairie where herds of bison, antelope and elk once grazed. Moderately dissected level to rolling plains with isolated sandstone buttes.