ABSTRACT

Regional cross sections constructed in the Paleocene-Eocene section of southern Mississippi to aid in the state's ongoing surface-geology mapping effort include a north-south section along 8846 W longitude, east-west sections along the 31^st parallel from Alabama to the Mississippi River, and a north-south section along the Mississippi Embayment axis. These cross sections showed the following correlations between the Wilcox producing zones of southwestern Mississippi and the Alabama type section: (1) the basal "Wilcox" sands, containing delta-sand lobes A & B, are equivalent to the Oak Hill Member (Naheola Formation, Midway Group), (2) the Minter Sand, generally the base of Wilcox production, is equivalent to the middle part of the Ostrea thirsae Bed (Nanafalia Formation, Wilcox Group), (3) the sometimes limy McKittrick Sand is equivalent to the Salt Mountain Limestone (top of the Ostrea thirsae bed), (4) the Big Shale and Baker Shale correlate respectively with the bottom and top of the Grampian Hills Member (Nanafalia Formation), (5) resistivity spikes on some geophysical logs spaced at one-and two-thirds intervals above the base of the Tuscahoma Formation may be the Greggs Landing and Bells Landing members, respectively, and (6) regressive-shale units above the concretionary, transgressive-marine sands of the Bashi Formation (basal Eocene) and the 4,600 Sand mark the base and the top of the Hatchetigbee Formation (upper-most Wilcox Group).