Thin-section, polished-surface, and X-ray analyses of 500 samples collected from the Jeffersonville Limestone at 14 localities in southeastern Indiana have permitted detailed correlation of carbonate facies. The Jeffersonville can be subdivided into 5 zones, each with its characteristic fauna and carbonate rock types. These zones overlap one another successively from south to north.

1. The lowest, or coralline zone, contains 3 distinct carbonate rock types, including (ascending) grain-supported biomicrite, biosparite, and biomicrudite. The lower biomicrite and biosparite units contain many branching corals, large colonial corals, and mound-like stromatoporoids. These fossils are found both in situ and overturned but generally are not fragmented. The upper biomicrudite contains a profusion of solitary corals and branching coral fragments. These strata are believed to have accumulated as a coral bank which was ripped occasionally by storm activity.

2. The Amphipora zone comprises biosparrudite in the lower part and biomicrudite in the upper part. Fragments of Amphipora and mat-like stromatoporoids are abundant. This zone reflects a shallowing of the water over the bank and may have resulted from upward growth of the coralline zone into a zone of greater wave activity. In Bartholomew County these strata swell to form a stromatoporoid bank with associated pelsparites and biopelsparites.

3. The Brevispirifer gregarius zone is characterized by mud-supported biomicrite containing Brevispirifer gregarius and charophyte oogonia. Corals and stromatoporoids are smaller and fewer. In Jennnings County, the position of these biomicrites is occupied by laminated and mud-cracked dolomites. These strata were deposited in water that was shallow enough to sustain the sessile algae and periodically expose the laminated beds.

4. The fenestrate bryozoan-brachiopod zone is composed of grain-supported biomicrite which intertongues northward in Jennings County with laminated dolomite beds. This zone contains fenestrate bryozoan fragments, small corals, and a diverse brachiopod fauna. Although shallow waters persisted toward the north, more normal marine conditions were re-established south of Jennings County.

5. The Paraspirifer acuminatus zone consists mainly of grain-supported biomicrite that contains Paraspirifer acuminatus, fenestrate bryozoans, small corals, and abundant echinoderm debris. This widespread zone overlaps the laminated beds toward the north and reflects deepening of the waters over the entire area and return to more normal marine conditions.

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