Geology and configuration of the top of the Tertiary limestone aquifer system, southeastern United States

The Tertiary limestone aquifer system of the southeastern United States is a thick sequence of carbonate rocks that vary in age and that are hydraulically connected in varying degrees. A map is presented that shows the altitude and configuration of the top of the aquifer system, as well as the extent of the youngest rock that is judged to be part of the system. Several types of geologic structures that affect the configuration of the top of the system may be readily recognized. (USGS)