An upper Santonian fauna dominated by the curved baculitid Boehmoceras Riedel, 1931, occurs as phosphatic moulds in the Tombigbee Sand Member of the Eutaw Formation in Mississippi and Alabama, and also is reworked into the base of the Mooreville Chalk; a similar assemblage is present in the middle part of the Pen Formation of the Big Bend area, Texas. The assemblage is: Pseudoschloenbachia (Pseudoschloenbachia) mexicana (Renz, 1936), Placenticeras syrtale (Morton, 1834), Reginaites leei (Reeside, 1927a), Reginaites exilis sp. nov., Texanites (Texanites) sp. juv. cf. gallicus Collignon, 1948, Texanites (Plesiotexanites) shiloensis Young, 1963, Texanitinae incertae sedis, Hyphantoceras (?) amapondense (van Hoepen, 1921).Glyptoxoceras spp., Boehmoceras arculus (Morton, 1834) and Scaphites (Scaphites) leei Reeside, 1927a, form I. The assemblage is referred to the uppermost Santonian Texanites (Plesiotexanites) shiloensis zone of the Gulf Coast sequence. Common occurrence of Scaphites (S.) leei I and Reginaites leei suggest correlation with the Upper Santonian Desmoscaphites erdmanni zone of the U.S. Western Interior; common occurrence of Boehmoceras arculus (= B. loescheri of European authors) suggests correlation with the Marsupites–granulata zone at the top of the North German Santonian. These data strengthen intercontinental correlation of the Santonian–Campanian boundary sequence. They also provide a biostratigraphic link to a numerical age of 84.2±0.9 Ma from a bentonite at a slightly lower level in the Tombigbee Sand Member of the Eutaw Formation in Mississippi.