ABSTRACT

Investigation of well-cutting samples from five drill holes penetrating the Lower Tuscaloosa Formation in the Sand Hill (Greene County), Stewart (Pearl River County), and McComb (Pike County) Fields revealed foraminifera from the early Late Cretaceous (Late Cenomanian) Rotalipora cushmani-greenhornensis biozone, and bivalve shells indicative of open marine shelf conditions. Samples from the Sand Hill Field contained the foraminifera Hedbergella delrioensis and Loeblichella hessi and bivalve shells. Samples from the Stewart Field contained the foraminifera Heterohelix moremani and Rotalipora appenninica and bivalve shells. Samples from the McComb Field contained only poorly-preserved, recrystallized specimens similar in general form, chamber arrangement, and size to Heterohelix moremani and Rotalipora greenhornensis. Age-correlation of foraminiferal species found in all three locations agrees with an assignment of all fossiliferous samples to the Rotalipora cushmani-greenhornensis biozone.

The presence of these Late Cenomanian (Woodbinian-Eaglefordian) foraminifera with open marine shelf bivalve remains suggests that marine conditions prevailed during the deposition of the Lower Tuscaloosa Formation across southern Mississippi, and correlate with similar open-marine shelf facies in the South Carlton Field in Clarke County, southwestern Alabama.