Sediments ranging in age from Pleistocene to Early Cretaceous (?) overlie metamorphosed basement rocks in most of coastal Georgia, but in southeastern Charlton County there are Paleozoic strata between the Lower Cretaceous (?) and the basement complex. The thickness of sediments ranges from 2,674 feet in Screven County, in the north, to 4,700 feet in Glynn County at the coast; the section thins somewhat toward Florida.

The Quaternary unit includes the surficial clastics of Recent to Pleistocene age. The Tertiary units include the predominantly clastic section of Miocene age; the Oligocene sandstones and their limestone equivalent, the Ocala Limestone; the Lisbon and Tallahatta clastics and their Avon Park-Lake City Limestone equivalents, the Wilcox clastics and their Oldsmar Limestone equivalent, all of Eocene age; and the Clayton and Tamesi Formations and their Cedar Keys Limestone equivalent of Paleocene age. The Upper Cretaceous units include the Lawson Limestone and the equivalent clastics of Navarro age; beds of Taylor and Austin age, both in clastic and limestone facies; and the clastic Tuscaloosa Formation. The oldest unit consists of clastics of Early Cretaceous(?) age; these sediments overl e metamorphosed basement rocks in the north and Paleozoics in the south. Two sections, one coastal and the other inland, show lithologic and faunal relationships which reflect changing depositional environments. Regionally, facies change from clastics in the north to limestones in the south with corresponding changes in microfossil suites. Tentative correlations of the clastic sections with their limestone equivalents are based on lithologic and fossil evidence.

There are no local geologic structures, but the sedimentary rocks of the area show the collective effects of the Carolina arch, the Southeast Georgia embayment, and the Ocala uplift.

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