Summary: "This report provides data on the alluvial aquifer of the Lower Mississippi Valley in the area between Cape Girardeau, Missouri, and Port Gibson, Mississippi. Maps are presented of the Tertiary surface on which the alluvial aquifer rests as well as the geology of this surface and the areas where hydrologic recharge to the alluvial aquifer may occur. A set of piezometric-surface maps, together with hydrographs of observation wells, river stages, precipitation rates, and data on the hydrologic properties of the alluvium, makes it possible to calculate changes which take place in the aquifer. Further data are presented on the chemical quality of groundwater. The relevance of these data to engineering problems is discussed" (p. ix).