The Drift Prairie is a geographic region of North and South Dakota. The gently rolling hills and shallow lakes were formed by glacial action, while the Badlands are characterized by the lack of this action, and the Red River Valley was a former lake bed. This distinction causes the area considered as Drift Prairie to overlap somewhat with the Missouri Plateau, another of North Dakota's distinct geographic regions, but the Drift Prairie also includes the Souris River basin. Prairie grasses and wheat grow there making it a perfect place for ranchers. The prairie is filled with drift. Drift is soil consisting of clay, sand, and gravel.