Investigations of formation-fluid salinities in a transect from western Georgia to the edge of the Blake Plateau off the coast of Georgia show surprisingly similar hydrochemical features offshore and onshore. A fresh-brackish wedge of groundwater (<25 g/kg total dissolved solids) lies beneath the shelf to a depth of ??? 900 m. On land, brackish waters extend to a maximum depth of ??? 1.2 km below sea level in Lowndes County, Georgia. In deeper horizons, hypersaline brines (> 100 g/kg) occur in Lower Cretaceous (?) strata. These strata have a pronounced evaporitic (anhydritic) character in the offshore segment. Strong salinity gradients in interstitial waters signify buried evaporite deposits at drill sites beneath the Blake Plateau. ?? 1981.