A detailed sedimentologic, mineralogic, and paleontologic study of an Upper Cretaceous sequence of clastic sediments in Alabama and Georgia has defined three regional deltaic facies for the Cusseta Sand.

Fluviatile and upper delta:
This facies is medium- to coarse-grained, poorly sorted sandstone and kaolinitic clay, with cut-and-fill structures, and unimodal trough-type cross-stratification.

Delta front:
The delta-front facies includes carbonaceous, micaceous siltstone and sandstone and mixed kaolinitic and montmorillonitic clay, abundant small mollusks and ostracods, estuarine and tidal channel deposits, bimodal cross-stratification, and Ophiomorpha borings associated with well-sorted, cross-bedded, "barrier-island" sandstone.

Prodelta:
The prodelta facies is fine- to coarse-grained, calcareous, glauconitic, fossiliferous sandstone and montmorillonitic clay. The mollusks Ostrea and Anomia are dominant, and there are abundant calcareous benthonic and planktonic Foraminifera.

Paleocurrent and light- and heavy-mineral data demonstrate southward transportation of immature sediments derived from a high-rank metamorphic and acid-igneous source in the southern Appalachians and Piedmont Plateau.

The Cusseta Sand has been interpreted previously as a basal unit in a transgressive sequence. The present study indicates that it represents the final coarsening upward or destructional phase of a positive regressive sequence. Previous difficulties in correlating thin discontinuous sandstone bodies in Alabama with the Cusseta Sand in Georgia are explained by their interpretation as barrier-island bars which developed during the destructional phase of the deltaic sequence.

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