Correlation of regional geohydrologic units to geological formations in southern Missouri

As part of the U.S Geological Survey's Regional Aquifer-System Analysis Program, geologic formations in southern Missouri (index map) were grouped into eight regional geohydrologic units on the basis of relative rock permeability and well yields (imes and Emmett, in press). Geohydrologic unit boundaries do not necessarily coincide with geologic unit boundaries or geologic time lines, but are determined by regional hydrologic properties, which may vary from one area to another.  The geologic formaitons were grouped into the geohydrologic units to determine the hydrologic characteristics of regional aquifer systems and associated regional confining units in parts of Arkansas, Kansas,Missouri, and Oklahoma.  This report presents a correlation of the regional geohydrologic units to corresponding geologic formations in southern Missouri.  Included in the report is a brief geologic history of southern Missouri.