Much of the Northem Plains Physiographic Province is characterized by extensive, planar erosion surfaces. Many of these surfaces are capped by gravel showing evidence of fluvial transport. This paper provides a description of the Cypress Hills Formation, Flaxville gravel, and related deposits. These deposits are very difficult to explain within uniformitarian geomorphological theory. A diluvial interpretation provides a superior explanation for the origin of these deposits. Implications of this interpretation are summarized, including problems with traditional age dating, likely formative processes for similar features found throughout the world, and the probable location of the Flood/post-Flood boundary in the geologic record.
