The Neogene of Bay County, Florida, contains three subsurface units, the Bruce Creek, St. Joe, and Intracoastal Formations which make up the Coastal Group and range in age from middle Miocene to Pliocene. They are overlain by a blanket of Pliocene-Pleistocene sands. The Bruce Creek Formation is the oldest of the three units (middle Miocene) and rests upon the Suwannee Limestone which is generally considered Oligocene in age.

The Bruce Creek, St. Joe, and Intracoastal units thicken southward down the paleoslope and pinch out toward the north. The Coastal Group extends laterally across Bay County and into neighboring counties to the east and west. Their full lateral extent is not known.

The St. Joe and Bruce Creek are fairly fossiliferous micrites which contain some quartz sand. The Intracoastal changes from a micrite in the west to a sandy clay in the east. The Intracoastal contains a large percentage of planktonic and benthic Foraminifera.

Biostratigraphic analysis of the Neogene of Bay County based on planktonic Foraminifera shows the Intracoastal Limestone to be Pliocene in the western part of the county (Globorotalia margaritae Zone) whereas it is significantly older in the east (G. fohsi fohsi Zone). The Bay County planktonic Foraminifera assemblages are somewhat unusual in that the presence of biostratigraphically useful planktonic Foraminifera assemblages in the nearshore Neogene sediments of the Gulf Coast is rare. The zonation schemes of Blow and Bolli which were developed in tropical sediments can be used only with difficulty in the temperate water sediments of the Florida Panhandle.

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