Preliminary notes on a detailed study of the eastern Gulf Oligocene are here presented. "Vicksburg group," a term formerly used by the United States Geological Survey to include all Oligocene deposits in this region, is restricted to a middle part of the Oligocene, namely, the Marianna limestone and the Byram formation. The Glendon limestone and Bucatunna clay are treated as members of the Byram formation. The Red Bluff clay and Forest Hill sand are regarded as lower Oligocene; the Chickasawhay limestone, here restricted to the "Lower Chickasawhay" of the Guidebook of the Eleventh Annual Field Trip of the Shreveport Geological Society, the Suwannee limestone,(FOOTNOTE 3) and the Flint River formation are regarded as upper Oligocene. The "Upper Chickasawhay" of the Guidebo k is here renamed the Paynes Hammock sand, with the type locality at Paynes Hammock, on the Tombigbee River in Clarke County, Alabama, and is regarded as basal Miocene. The Paynes Hammock sand intertongues at the west with non-fossiliferous beds referred to the Catahoula sandstone, with the Paynes Hammock tongue below the Catahoula tongue. The Paynes Hammock sand and equivalent beds on the west referred to the Catahoula sandstone are correlated with the Tampa limestone.