This map presents the configuration of the bottom of the Floridan aquifer in the Southwest Florida Water Management District. The bottom of the aquifer generally corresponds to the beginning of consistent intergranular evaporites occurring in either the Avon Park, Lake City, or Oldsmar Limestones of Eocene age. The altitude of the bottom of the aquifer varies from about 600 feet below the National Geodetic Vertical Datum of 1929 in the north to about 3,000 feet below the datum in the South. (Kosco-USGS)