Fourteen consecutive field seasons of scientific excavations of alluvial deposits of the lower Pomme de Terre Valley, southeastern Missouri, have provided a radiocarbondated (154 analyses) chronostratigraphic sequence in four terraces reflecting five major episodes of aggradation and degradation. Probably all of Wisconsinan time and the Holocene is represented. A sixth alluvial deposit is probably Illinoian and possibly older Pleistocene alluvium. Spring deposits within the terraces contain bone beds associated with peat lenses containing pollen, plant, and beetle remains, all of which have provided paleoecological data.

The springs appear to have erupted initially, in response to either tectonic disturbance or hydrostatic...