The Kansan glaciation should be representative of Early Pleistocene glaciations in the Kansas-Nebraska-Iowa-Missouri region. It is often assumed the Kansan ice-sheet advanced as a single, broad lobe coming from somewhere in Canada. This simple view contrasts with the known complexities of the younger Wisconsin glaciation, and indeed there is much evidence that the Kansan glaciation was equally complex. A two-ice-Iobe model for the Kansan glaciation includes two confluent ice-streams, Dakota Ice and Minnesota Ice, both moving generally southward either side of the Coteau des Prairies in eastern South Dakota. Iowa and Missouri were covered mainly by Minnesota Ice, while Dakota Ice advanced into Nebraska and Kansas. The general boundary zone between the two ice-lobes is marked by the Kansas City re-entrant and by the Missouri River north of Kansas City, which may have developed as an interlobate drainage during deglaciation
