The Devils Lake region of northeastern North Dakota is covered with glacial drift deposited by the Leeds lobe of the Mankato Substage of the Wisconsin Stage of the Pleistocene and is underlain by Pierre Shale of Cretaceous age. Associated with the Sheyenne River, which flows through the southern part of the region in a deep trench, are many stream terraces, spillways, deposits of ice-contact stratified drift, and eroded ground-moraine areas. Six stages of drainage have been established to which these various features can be assigned. In the first two stages the features formed as melt water drained to the glacial James River south of the region and as the ice front stood at and later retreated from the site of the Heimdal moraine, a recessional moraine of the Leeds lobe. The later stages occurred after the valley of the Sheyenne River was free of ice and after glacial Lake Souris northwest of the region drained down the valley to glacial Lake Agassiz in the eastern part of the state. Features originating during the four later stages are largely related to the deposition of the North Viking moraine (another, more northern, recessional moraine of the Leeds lobe) and subsequent retreat of the ice from the moraine. Discharge from the local Devils and Stump lakes and from glacial Lake Souris also were of considerable importance in the genesis of many features.
