Altitude and configuration of the top of the Floridan Aquifer, Duval County, Florida

Structural contours on the top of the Floridan aquifer in Duval County, Florida, show that the top of the aquifer ranges from less than 300 feet below sea level to more than 600 feet below sea level. Two inferred concealed faults occur in the aquifer; one trending northeast-southwest in the eastern part of the county. The maximum vertical displacement of the top of the aquifer of both faults is about 150 feet. A geologic section included on the map shows the geologic formations of Eocene age that comprise the Floridan aquifer. These are, in ascending order: the Lake City Limestone, the Avon Park Limestone, and the Ocala Limestone. (Woodard-USGS)