Salem Limestone



Type designation:

Type locality: The name “Salem Limestone” was proposed by Cumings (1901) to replace the preoccupied name "Bedford Limestone" for rocks lying between the Harrodsburg Limestone (below) and the Mitchell Limestone (above) (Rexroad, 1986). No type section was designated; however, Cumings (1901) quoted a section described by Gorby (1886, p. 143).

Reference section: Because the designated section has been quarried away, the abandoned part of the Hanson Aggregates Salem Quarry in the NE¼ sec. 24, T. 2 N., R. 3 E., on the west edge of Salem, Washington County, Indiana, was designated by Smith (1970, p. 152) as the principal reference section (Rexroad, 1986).

History of usage:

Early local names (Information modified from Rexroad, 1986): From the first quarry record of the Salem Limestone in 1827 until the late 1800s, quarrymen did not realize the lateral continuity of the Salem Limestone, so that the building stone was sold under many local names. Another and widely used quarry term is Bastard stone, which refers to an upper impure and normally discarded part of the Salem. Variations of the local term “Spergen Hill” or “Spergen” were also in use, primarily because of the renown of that locality in Washington County, Indiana, as a fossil-collecting site.

Formal name: Because the name “Bedford stone” came to dominate the building-stone industry, the Salem was formally named the Bedford Oolitic Limestone by Hopkins and Siebenthal (1897) (Rexroad, 1986).

Renamed: Cumings (1901) renamed the unit the Salem Limestone because the name “Bedford” was preoccupied by the Bedford Shale of Ohio (Newberry, 1871).

Renamed: E. O. Ulrich (as published by Buckley and Buehler, 1904, p. 110) adopted the term “Spergen Hill Limestone,” which evolved to the Spergen Limestone (Wilmarth, 1938). Although the Indiana Geological Survey and the Illinois State Geological Survey consistently used the name “Salem,” it was not until the 1950s that the U.S. Geological Survey changed its use from "Spergen Limestone" to "Salem Limestone." (See Smith, 1970, p. 152-153.)

Trade name: The Salem Limestone is generally known in the building-stone trade as the Indiana Limestone (Rexroad, 1986).


The most widely known rock type of the Salem Limestone is crossbedded calcarenite that is medium to coarse grained, tan, gray tan, and light gray, porous, and fairly well sorted and that occurs in exceptionally thick beds (Rexroad, 1986). Individual grains are mostly microfossils (including especially the foraminiferid Globoendothyra baileyi), macrofossil fragments, and whole diminutive forms of macrofossils (Rexroad, 1986). Coated grains are also common. Other lithologies include much finer and coarser calcarenites, biocalcirudites, very fine grained argillaceous dolostone commonly containing wavy black carbonaceous laminae, very fine grained to dense limestone in places including oolites, and dense argillaceous dark-gray to dark-brown limestone (Pinsak, 1957).

Distribution and thickness: The Salem crops out along an irregular arcuate line extending from northwestern Putnam County to the Ohio River at the east edge of Harrison County (Rexroad, 1986). Commonly it is 60 to 100 ft (18 to 30 m) thick along the central and southern parts of the outcrop belt; it is thinner to the north. The northern limit is difficult to place because it is near a depositional pinchout of the Salem and was also affected by pre-Pennsylvanian erosion and, therefore, is very irregular (Rexroad, 1986). The Salem is everywhere present in the subsurface south and west of the outcrop-pinchout belt. Subsurface thickness of the Salem is variable, but in much of southwestern Indiana it averages about 175 ft (52 m) (Rexroad, 1986). The Salem reaches a maximum thickness of about 280 ft (85 m) in northwestern Posey County and southeastern Gibson County (Keller and Becker, 1980, p. 15-16).


Where the basal Somerset Shale Member is absent, it is difficult to recognize the conformable Harrodsburg Limestone-Salem Limestone boundary (Rexroad, 1986). The more obvious lithologic changes at the boundary represent shifting ecologic conditions rather than a hiatus (Rexroad, 1986). Similarly, vertical transition or even lateral gradation between lithologies representative of the Salem and the overlying St. Louis Limestone is the general situation in the subsurface of the Illinois Basin (Lineback, 1972), but in part of the Indiana outcrop belt the evidence of continuity of deposition between the Salem and the St. Louis is not strong. In places, along its northern limits, the Salem is unconformably overlain by the Pennsylvanian Mansfield Formation (Rexroad, 1986).


The Salem Limestone is identified throughout the Illinois Basin in Illinois and Kentucky and maintains about the same stratigraphic relationships throughout (Rexroad, 1986). It is somewhat younger in Indiana than in western Illinois, however, and from Madison County northward in Illinois the upper part of the Salem grades laterally into the St. Louis Limestone (Lineback, 1972). The Salem is within the Taphrognathus varians-Apatognathus Assemblage Zone of conodonts (Collinson, Rexroad, and Thompson, 1971). It correlates with rocks within the TC Zone of Neves and others (1972), which is based on spores, and approximately with rocks within North American foraminiferal Zones 10, 11, and 12 of Mamet and Skipp (1971) (Rexroad, 1986). In European terms it is early Visean in age (Rexroad, 1986).

Regional Indiana usage:

Illinois Basin (COSUNA 11)
Supergroup: none
Group: Sanders Group
Formation: Salem Limestone
Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: Sanders Group
Formation: Salem Limestone
Cincinnati Arch (COSUNA 13)
Supergroup: none
Group: Sanders Group
Formation: Salem Limestone

Misc/Abandoned Names:

Bastard stone, Bedford Limestone, Bedford Oolitic Limestone, Bedford stone, Bloomington stone, Ellettsville stone, Indiana Limestone, Salem stone, Spergen fossil bed, Spergen Hill Limestone, Spergen Limestone, Spergen's Hill bed, White River stone

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.)

Map showing the COSUNA areas (heavy black line) that approximate regional bedrock outcrop patterns and major structural features in Indiana, and the COSUNA numbers (large bold font) for these areas. The COSUNA boundaries are limited to state and county boundaries that facilitate coding.

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

Map showing major tectonic features that affect bedrock geology in Indiana.

Major tectonic features that affect bedrock geology in Indiana.


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

Cumings, E. R., 1901, The use of Bedford as a formational name: Journal of Geology, v. 9, p. 232-233.

Gorby, S. S., 1886, Geology of Washington County: Indiana Department of Geology and Natural History Annual Report 15, p. 117-153.

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.

Hopkins, T. C., and Siebenthal, C. E., 1897, The Bedford Oolitic Limestone: Indiana Department of Geology and Natural Resources Annual Report 21, p. 289-427.

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.

Lineback, J. A., 1972, Lateral gradation of the Salem and St. Louis Limestones (Middle Mississippian) in Illinois: Illinois State Geological Survey Circular 474, 21 p.

Mamet, B. L., and Skipp, B. A., 1971, Lower Carboniferous calcareous Foraminifera–preliminary zonation and stratigraphic implications for the Mississippian of North America: Sixieme Congres International de Stratigraphie et de Geologie du Carbonifere Sheffield, 1967, Compte rendu, v. 3, p. 1,129-1,146.

Neves, R., Gueinn, K. J., Clayton, G., Ioannides, N., and Neville, R. S. W., 1972, A scheme of miospore zones for the British Dinantian: Septieme Congres International de Stratigraphie et de Geologie du Carbonifere Krefeld, 1971, Compte rendu, v. 1, p. 347-353.

Newberry, J. S., 1871, Report on the progress of the Geological Survey of Ohio in 1869: Ohio Geological Survey, pt. 1, p. 1-53.

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

Rexroad, C. B., 1986, Salem 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. 132-133.

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.

Wilmarth, M. G., 1938, Lexicon of geologic names of the United States (including Alaska): U.S. Geological Survey Bulletin 896, 2,396 p.

For additional information contact:

Nancy Hasenmueller (hasenmue@indiana.edu)
Date last revised: July 28, 2017

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