Mississippi is considered to be a proved oil province. Possibilities of future petroleum provinces within the state must underlie those which are currently producing. Practically the entire stratigraphic sequence from Ordovician to Recent is represented in Mississippi (Fig. 111).

Most of the current production is from rocks of Upper Cretaceous age. Some fields are producing from the Wilcox of Eocene age; a few wells have been completed in the Comanche series of Lower Cretaceous age; and a few in the Claiborne formation of Eocene age. The depleted Amory field produced gas from the Chester (Upper Mississippian).

The area of Mississippi is 48,865 square miles. The section of sedimentary rocks is 5,000 feet thick in a small area in northwestern Mississippi and is estimated as 30,000 feet or more thick in the southwestern part of the state.

South Alabama.—The south half of Alabama includes 22,000 square miles and is underlain by a sedimentary section varying in thickness from zero at the contact of the sedimentary-basement complex to possibly more than 25,000 feet on the coast in the vicinity of Mobile. The total volume of these sediments is probably in excess of 55,000 cubic miles.

The post-Paleozoic sediments range in age from Jurassic to Recent and are composed of shale, sand, and limestone.

The regional structure of south Alabama is that of a south-southwest-dipping homocline, interrupted in southwest Alabama by the Hatchetigbee anticline and the Jackson fault, located in Choctaw, Clarke, and Washington counties.

South Alabama has one producing oil field, the