Mississippian System

Type locality and history of name in Indiana: The Ste. Genevieve Limestone was named by Shumard (1860, p. 406; 1873, p. 293-294) for exposures in the bluff of the Mississippi River south of Ste. Genevieve, Mo. The name was mostly suppressed, however, in favor of the term St. Louis Limestone until it was revived by Ulrich and Smith (1905). At the type locality the formation is about 100 feet (30 m) thick. Beede and others (1915, p. 207) suggested that the Ste. Genevieve Limestone is present in Indiana, but it remained for Cumings (1922, p. 507) to use the name directly. Before that time, rocks now designated as the Ste. Genevieve in Indiana had been assigned to the Mitchell Limestone (see under "Blue River Group") or to the Paoli or St. Louis Limestones.

Although Cumings's description was not thorough, use of the name Ste. Genevieve was continued in Indiana. Only much later were comprehensive descriptions of the formation and its subdivisions in Indiana presented (McGrain, 1943? Malott, 1952). As described by Malott (1952, p. 8-10), the Ste. Genevieve extended from 20 feet (6 m) or so below the Lost River Chert Bed near the base of the formation to the top of the Bryantsville Breccia Bed, and it consisted in ascending order of the Fredonia, Rosiclare Sandstone (now Spar Mountain), and Levias Members. The Ste. Genevieve was later placed in the middle of the Blue River Group by Gray, Jenkins, and Weidman (1960, p. 48).

The top of the Ste. Genevieve in subsurface usage is placed at the base of the Aux Vases Formation, a position that is generally considered to be somewhat lower stratigraphically than in lndiana outcrop usage (fig. 2; Pinsak, 1957; Swann, 1963). The Ste. Genevieve of Indiana surface usage therefore differs from usage in the subsurface and in type areas in Illinois.

Description: The Ste. Genevieve Limestone in Indiana is a carbonate-rock sequence that is 45 to 220 feet (14 to 67 m) thick and that thickens southward and southwestward. Its constituent beds are composed largely of oolitic, skeletal, micritic, and detrital limestone. Shale, dolomite, sandstone, and chert compose about 10 percent of the combined Paoli and Ste. Genevieve Limestones (Carr, Leininger, and Golde, 1978, p 14). The Ste. Genevieve crops out in a northward-narrowing belt from the Ohio River in Harrison and Crawford Counties to west-central Putnam County. It is present throughout the Indiana subsurface south of the central parts of Parke and Vermillion Counties and west of its outcrop belt.

The upper contact of the Ste. Genevieve with the Paoli Limestone is somewhat uneven but seems to represent only a minor depositional break (Perry and Smith, 1958, p. 32-33; Gray, Jenkins, and Weidman, 1960, p. 50). North from central Putnam County the Ste. Genevieve is disconformably overlapped by Pennsylvanian rocks. Opinion on the St. Louis-Ste. Genevieve boundary in Indiana, partly from different points of observation, ranges from one of unconformity (Bates, 1932, p. 268) to one of transition (Perry, Smith, and Wayne, 1954, p. 30), and according to some opinion (for example, Woodson, 1982), the boundary should be placed somewhat higher than indicated here, and above the Lost River Chert Bed.

Correlation and boundary problems: Correlation of the Ste. Genevieve Limestone of Indiana usage is beset with problems associated with the upper boundary, the lower boundary, and certain members of the formation. Current concepts (summarized in fig. 2) are based partly on physical continuity of units and partly on paleontologic criteria.

Platycrinites penicillus has been reported in the Bryantsville Breccia Bed at the top of the Levias of Indiana, and Talarocrinus has been reported in the overlying Paoli Limestone (Malott, 1952, p. 9, 12). The presence of these fossils indicates that the Ste. Genevieve-Paoli boundary closely approximates the Valmeyeran-Chesterian boundary and that the upper part of the Levias Member of Indiana correlates with the Levias Limestone Member of the Renault Limestone in the Mississippi Valley area. The Spar Mountain Member of the Ste. Genevieve in Indiana is essentially continuous into the Spar Mountain Sandstone Member in southeastern Illinois, so that the remaining part of the Levias must correlate with the Aux Vases Sandstone and with the Joppa Member and the Karnak Limestone Member of the Ste. Genevieve Limestone of Illinois (fig. 2). Conodonts from each of these units represent the Gnathodus bilineatus-Cavusgnathus charactus Assemblage Zone (Rexroad and Fraunfelter, 1977, p. 94-97; Collinson, Rexroad, and Thompson, 1971, p. 383).

The Ste. Genevieve Limestone in the Illinois Basin is characterized by the crinoid Platycrinites penicillus Meek and Worthen and the brachiopod Pugnoides ottumwa (White), but both species are uncommon in Indiana. According to Mamet and Skipp (1971), the Ste. Genevieve correlates within foraminiferal Zone 15 and within the Visean Series (approximately Zone V3b) of European usage. Their samples are now believed to have been collected, however, from the St. Louis Limestone in the Ste. Genevieve area of Missouri. The Ste. Genevieve more likely correlates, therefore, with foraminiferal Zone 16i (approximately V3c of European usage).

Although the lower boundary of the Ste. Genevieve is now placed about 20 feet (6 m) below the Lost River Chert Bed, this bed was included in the St. Louis by Cumings (1922, p. 507) and was placed in the Horse Cave Member of the St. Louis by Woodson (1982). Woodson's Horse Cave includes much of the Fredonia as here described and contains conodonts found in the St. Louis Limestone not only at its type locality but also at the type locality of the Ste. Genevieve. These represent the Apatognathus scatenus-Cavusgnathus Assemblage Zone, which indicates a correlation of the lower Fredonia of Indiana usage with the upper part of the St. Louis Limestone and also indicates a hiatus within the Fredonia of Indiana (Rexroad and Fraunfelter, 1977, p. 85).