Type designation:

Type area: The name "St. Louis Limestone" was first used by Engelmann (1847, p. 119-120) with reference to extensive exposures of limestone near St. Louis, Missouri (Carr, 1986).

History of usage:

Present use stems from E. O. Ulrich's suggestion (Buckley and Buehler, 1904, p. 109-110) of restricting the St. Louis Limestone to the limestone above the Spergen Limestone (now called the Salem Limestone) and below the Ste. Genevieve Limestone (Smith, 1970; Carr, 1986).

Early stratigraphic nomenclature in Indiana included in the Mitchell Limestone rocks that are now assigned to the St. Louis, Ste. Genevieve, and Paoli Limestones (Carr, 1986). Beede and others (1915, p. 207) noted that the St. Louis and the Ste. Genevieve could be differentiated, and most authors since that time have attempted to recognize a distinction between those formations (Carr, 1986). Few vertically extensive exposures and no reference sections exist in the state, however, and the St. Louis-Ste. Genevieve boundary has been a particularly difficult one to establish (Carr, 1986).


The St. Louis Limestone in Indiana can be divided into two parts on the basis of lithology (Pinsak, 1957, p. 23-24). The upper St. Louis, which is the upper one-eighth to one-third of the formation, consists mainly of thin beds of medium- to dark-gray-brown micritic, pelletal, and skeletal limestone and very thin beds of medium-gray shale (Carr, Leininger, and Golde, 1978, p. 79). Nodules and thin discontinuous beds of mottled light- and dark-gray dense chert are generally abundant in the upper 25 to 90 ft (8 to 27 m) of the unit; thin-bedded silty dolostone is as much as 20 percent of the total in places (Carr, 1986). The lower St. Louis on outcrop consists mainly of pellet-micritic limestone, calcareous shale, and silty dolostone (Carr, 1986).

In the subsurface in a large belt across southern Illinois, southwestern Indiana, and north-central Kentucky, the carbonates and shale of the lower St. Louis are interbedded with anhydrite and gypsum to a total thickness exceeding 160 ft (49 m) (McGregor, 1954, pl. 2; Jorgensen and Carr, 1973, p. 46). Evaporite deposition was cyclical and produced as many as 18 distinct repetitions of lithologies (Carr, 1986). In the subsurface of southwestern Indiana, a distinct lower St. Louis facies consisting of calcarenite interbedded with variable lithologies was designated the Sisson Member by Keller and Becker (1980, p. 11-15). In the subsurface, Droste and Carpenter (1990) used the X marker identified by Keller and Becker (1980) to divide the St. Louis into informal lower and upper parts. The X marker horizon, a characteristic signature on electric logs, is caused by light-colored dolostones directly above and by nonporous limestones containing scattered chert directly below (Droste and Carpenter, 1990).

The unit is 70 ft (21 m) thick in Putnam County; it thickens irregularly southward to about 150 ft (46 m) in Washington County (Sunderman, 1968, p. 26). In a quarry in southernmost Crawford County it is 300 ft (91 m) thick (Carr, Leininger, and Golde, 1978, p. 18). It thickens to more than 550 ft (167.6 m) in Posey County in southwestern Indiana (Droste and Carpenter, 1990). Most of the thickening and thinning appears to take place in the lower part of the formation (Pinsak, 1957, p. 23).

Distribution: The St. Louis Limestone crops out from Harrison County on the Ohio River to northeastern Parke County, where it is overlapped by Pennsylvanian rocks (Carr, 1986).


The St. Louis conformably overlies the Salem Limestone and underlies Lost River Chert Bed of Fredonia Member of Ste. Genevieve Limestone (Droste and Carpenter, 1990).


By means of the corals Lithostrotion proliferum, Lithostrotionella castelnaui, and L. hemisphaerica, the St. Louis Limestone of Indiana is correlated with the type St. Louis (Carr, 1986). The upper part of the formation belongs in the Apatognathus scalenus-Cavusgnathus Assemblage Zone (conodonts), to which the upper part of the type St. Louis has also been assigned (Collinson, Rexroad, and Thompson, 1971).

Regional Indiana usage:

Illinois Basin (COSUNA 11)
Supergroup: none
Group: Blue River Group
Formation: St. Louis Limestone
Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: Blue River Group
Formation: St. Louis Limestone
Cincinnati Arch (COSUNA 13)
Supergroup: none
Group: Blue River Group
Formation: St. Louis Limestone

Misc/Abandoned Names:


Geologic Map Unit Designation:


Note: Hansen (1991, p. 52) in Suggestions to authors of the reports of the United States Geological Survey noted that letter symbols for map units are considered to be unique to each geologic map and that adjacent maps do not necessarily need to use the same symbols for the same map unit. Therefore, map unit abbreviations in the Indiana Geologic Names Information System should be regarded simply as recommendations.

COSUNA areas and regional terminology

Names for geologic units vary across Indiana. The Midwestern Basin and Arches Region COSUNA chart (Shaver, 1984) was developed to strategically document such variations in terminology. The geologic map (below left) is derived from this chart and provides an index to the five defined COSUNA regions in Indiana. The regions are generally based on regional bedrock outcrop patterns and major structural features in Indiana. (Click the maps below to view more detailed maps of COSUNA regions and major structural features in Indiana.)

COSUNA areas and numbers that approximate regional bedrock outcrop patterns and major structural featuers in Indiana.

Major tectonic features that affect bedrock geology in Indiana.


Beede, J. W., Jackson, T. F., and Malott, C. A., 1915, Geology of the Bloomington quadrangle: Indiana Department of Geology and Natural Resources Annual Report 39, p. 190-312.

Buckley, E. R., and Buehler, H. A., 1904, Quarrying industry of Missouri: Missouri Bureau of Geology and Mines, 2nd Series, v. 2, 371 p.

Carr, D. D., 1973, Geometry and origin of oolite bodies in the Ste. Genevieve Limestone (Mississippian) in the Illinois Basin: Indiana Geological Survey Bulletin 48, 81 p.

Carr, D. D., 1986, St. Louis Limestone, in Shaver, R. H., Ault, C. H., Burger, A. M., Carr, D. D., Droste, J. B., Eggert, D. L., Gray, H. H., Harper, Denver, Hasenmueller, N. R., Hasenmueller, W. A., Horowitz, A. S., Hutchison, H. C., Keith, B. D., Keller, S. J., Patton, J. B., Rexroad, C. B., and Wier, C. E., Compendium of Paleozoic rock-unit stratigraphy in Indiana–a revision: Indiana Geological Survey Bulletin 59, p. 125-126.

Carr, D. D., Leininger, R. K., and Golde, M. V., 1978, Crushed stone resources of the Blue River Group (Mississippian) of Indiana: Indiana Geological Survey Bulletin 52, 225 p.

Collinson, Charles, Rexroad, C. B., and Thompson, T. L., 1971, Conodont zonation of the North American Mississippian: Geological Society of America Memoirs 127, p. 353-394.

Droste, J. B., and Carpenter, G. L., 1990, Subsurface stratigraphy of the Blue River Group (Mississippian) in Indiana: Indiana Geological Survey Bulletin 62, 45 p.

Engelmann, George, 1847, Remarks on the St. Louis Limestone: American Journal of Science, ser. 2, v. 3, p. 119-120.

Hansen, W. R., 1991, Suggestions to authors of the reports of the United States Geological Survey (7th ed.): Washington, D.C., U.S. Geological Survey, 289 p.

Jorgensen, D. B., and Carr, D. D., 1973, Influence of cyclic deposition, structural features, and hydrologic controls on evaporite deposits in the St. Louis Limestone in southwestern Indiana, in Eighth Forum on Geology of Industrial Minerals Proceedings: Iowa Geological Survey Public Information Circular 5, p. 43-65.

Keller, S. J., and Becker, L. E., 1980, Subsurface stratigraphy and oil fields in the Salem Limestone and associated rocks in Indiana: Indiana Geological Survey Occasional Paper 30, 63 p.

McGregor, D. J., 1954, Gypsum and anhydrite deposits in southwestern Indiana: Indiana Geological Survey Report of Progress 8, 24 p.

Pinsak, A. P., 1957, Subsurface stratigraphy of the Salem Limestone and associated formations in Indiana: Indiana Geological Survey Bulletin 11, 62 p.

Shaver, R. H., coordinator, 1984, Midwestern basin and arches region–correlation of stratigraphic units in North America (COSUNA): American Association of Petroleum Geologists Correlation Chart Series.

Smith, N. M., 1970, Salem Limestone, in Shaver, R. H., Burger, A. M., Gates, G. R., Gray, H. H., Hutchison, H. C., Keller, S. J., Patton, J. B., Rexroad, C. B., Smith, N. M., Wayne, W. J., and Wier, C. E., Compendium of rock-unit stratigraphy in Indiana: Indiana Geological Survey Bulletin 43, p. 152-155.

Sunderman, J. A., 1968, The geology and mineral resources of Washington County, Indiana: Indiana Geological Survey Bulletin 39, 90 p.

For additional information contact:

Nancy Hasenmueller (
Date last revised: February 8, 2018