Age:

Mississippian

Type designation:

Reference sections: Although first used by Patton (1949, p. 8), the name “Bryantsville Breccia” is usually attributed to Malott (1952, p. 9, 95-97), who wrote of the following three specific typical exposures near Bryantsville, Lawrence County, Indiana:

(1) on the north side of U.S. Highway 50 in the NW¼NW¼ sec. 25, T. 4 N., R. 2 W., 1 mile (1.6 km) southwest of Bryantsville, and

(2 and 3) in two quarries in the SW¼NW¼ and the SE¼NE¼ sec. 20, T. 4 N., R. 1 W., 1¼ and 2 miles (2.0 and 3.2 km) east of Bryantsville (Carr, 1986).

History of usage:

Named: The unit was named the “Bryantsville bed” of Levias Member of Ste. Genevieve Limestone by Patton (1949, p. 8). The name was taken from an unpublished manuscript by C. A. Malott.

Revised assignment: The breccia was designated as a bed at the top of the Karnak Member of the Ste. Genevieve Limestone by Droste and Carpenter (1990, fig. 2A).

Description:

The breccia fragments of the Bryantsville Breccia Bed are angular to subangular; consist of dense micritic limestone and partly to wholly oolitic limestone; and are bound together by a matrix consisting of calcite, finely divided limestone fragments, oolitic limestone, and, less commonly, chert (Carr, 1986). The fragments range from 0.01 to 0.4 ft (0.3 to 12.2 cm) in breadth and are commonly dark gray to dark blue gray (Carr, 1986). The binding material, possibly of algal origin and in sinuous subparallel laminae, ranges in color from lighter to darker than the fragments (Carr, 1986). A zone of color-banded and wavy-laminated cherty or siliceous limestone or of nonsiliceous limestone is found in many exposures of the Bryantsville and in places is its only expression (Carr, 1986).

The breccia occurs in one or more beds and is as much as 12 ft (3.7 m) thick, although in places it is only a few inches thick (Carr, 1986). Other less persistent breccias and other lithologies similar to the Bryantsville are found in the overlying Paoli Limestone and at other horizons in the Ste. Genevieve Limestone (Perry and Smith, 1958, p. 35; Carr, 1986). These are difficult to distinguish from the Bryantsville unless enough thickness of section is available to place the breccia with respect to other identifiable stratigraphic units (Carr, 1986).

Distribution: The Bryantsville Breccia Bed marks the top of the Ste. Genevieve Limestone throughout the outcrop belt in Indiana (Carr, 1986). According to Malott (1952, p. 9-10) and McFarlan and others (1955), the Bryantsville extends into western Kentucky in the southern part of the Illinois Basin.

Correlations:

In Kentucky, the bed is placed in the Ste. Genevieve partly on the basis of the presence of the crinoid Platycrinites penicillus (Malott, 1952, p. 9), and on the same basis it is assigned to Swann's (1963, p. 20-21) Genevievian Stage, Valmeyeran Series (Atherton, Collinson, and Lineback, 1975, p. 141-142).

Regional Indiana usage:

Illinois Basin Margin (COSUNA 12)
Supergroup: none
Group: Blue River Group
Formation: Ste. Genevieve Limestone
Member: Joppa Member
Bed: Bryantsville Breccia Bed

Misc/Abandoned Names:

None

Geologic Map Unit Designation:

Msgb

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 features in Indiana.

Major tectonic features that affect bedrock geology in Indiana.

References:

Atherton, Elwood, Collinson, Charles, and Lineback, J. A., 1975, Mississippian System, in Willman, H. B., Atherton, Elwood, Buschbach, T. C., Collinson, Charles, Frye, J. C., Hopkins, M. E., Lineback, J. A., and Simon, J. A., Handbook of Illinois stratigraphy: Illinois State Geological Survey Bulletin 95, p. 123–163.

Carr, D. D., 1986, Bryantsville Breccia Bed, 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. 23.

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.

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

Malott, C. A., 1952, Stratigraphy of the Ste. Genevieve and Chester formations of southern Indiana: Ann Arbor, Michigan, Edwards Letter Shop, 105 p.

McFarlan, A. C., Nosow, Edmund, and Swann, D. H., 1955, Some old Chester problems–correlations of lower and middle Chester formations of western Kentucky: Kentucky Geological Survey, ser. 9, Bulletin 16, 37 p.

Patton, J. B., 1949, Crushed stone in Indiana: Indiana Division of Geology Report of Progress 3, 47 p.

Perry, T. G., and Smith, N. M., 1958, The Meramec-Chester and intra-Chester boundaries and associated strata in Indiana: Indiana Geological Survey Bulletin 12, 110 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.

Swann, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.