A 2,102-foot observation well was drilled at Fernandina Beach, Florida, to obtain geologic and hydrologic data. Drill cuttings, water samples, and water-level measurements were collected. Geologist's, driller's, and geophysical logs were completed. The well is constructed with 12-inch diameter casing to a depth of 515 feet and 6-inch diameter casing from 515 to 2,000 feet. The remainder is open hole. The uppermost 500 feet of material penetrated by the well consists of sand, clay, limestone, and dolomite. In the remainder of the hole, the material consists of fragmental and granular limestone and massive to finely crystalline dolomite, which comprise the Floridan aquifer in the area. After the well was completed, water levels in the monitored zone, 2,000 to 2,102 feet, were above land surface. During July and August 1979, water levels ranged from about 8 to 13 feet above land surface. Chloride concentrations of water sampled through the drill stem from a depth of 632 to 2,039 feet ranged from 25 to 710 milligrams per liter. Chloride increased markedly below 2,039 feet to a maximum of 7,800 milligrams per liter at 2,094 feet. After completion of the well, chloride was 8,100 milligrams per liter.
