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USGS1926

Correlation of the basal Cretaceous beds of the Southeastern States

The basal Cretaceous deposits that fringe the inner margin of the Coastal Plain from eastern Alabama to central North Carolina, where they are overlapped by Miocene sands, have been commonly classified as of Lower Cretaceous age and correlated roughly with the Patuxent formation of the Potomac group of Maryland and Virginia. In this paper the evidence on which this early correlation was based is reviewed, later evidence is considered, and the conclusion is reached that all the basal Cretaceous deposits in the area under consideration are of Upper Cretaceous age. Acknowledgments are gratefully made of the helpful criticism of the manuscript by L. W. Stephenson and of his generous assistance in the preparation of the correlation table.

Alabama;Georgia;North Carolina;South Carolina↗

USGS1925

Correlation of the Eocene formations in Mississippi and Alabama

During Eocene time the site of the boundary between the States of Mississippi and Alabama fell within the transition zone between the Mississippi embayment and the open Gulf of Mexico. That different types of deposition proceeded simultaneously within these two regions may be inferred from the different facies which deposits of the same age exhibit on opposite sides of the State line. In general, much clay and carbonaceous material were laid down in Mississippi, while shell marl, laminated sand, and limestone were being formed in Alabama. The purpose of this paper is to point out the equivalences of formations of different facies in the two States. The formations of different facies in the two States. The correlation adopted in shown in the following table, all the formation names in which have been previously used, except Kosciusko sandstone, a new name proposed for a member of the Lisbon formation.

Alabama;Mississippi↗