Named: The name "Big Clifty Sandstone" is generally credited to Norwood (1876); however, he did not specifically indicate the source of the name (Gray, 1986). Presumably it derives from Big Clifty Creek in Grayson County, Kentucky (Butts, 1917, p. 87; Atherton and others, 1975, p. 157; Gray, 1986).
History of usage:
Miscorrelation: A major part of the Big Clifty Formation on the outcrop in Indiana is a prominent cliff-forming sandstone that for many years was referred to as the Cypress Sandstone (Malott, 1931, 1952; Gray, 1970, 1986).
In many places the Big Clifty Formation is composed in descending order of 3 to 14 ft (1 to 4 m) of gray fossiliferous shale and interbedded limestone, 3 to 10 ft (1 to 3 m) of varicolored mudstone and siltstone, 25 to 40 ft (8 to 12 m) of thin-bedded fine-grained sandstone, and in places as much as 6 ft (2 m) of black pyritiferous shale at the base (Gray, 1986). The two upper units are assigned to the Indian Springs Shale Member. On the outcrop the sandstone member of this formation is a conspicuous cliff former of great lateral extent (Gray, Jenkins, and Weidman, 1960, p. 40-41), but downdip in the subsurface of southwestern Indiana the formation is primarily shale, and the sandstone, sometimes referred to by drillers as the Jackson Sand, occurs as isolated lenses (Gray, 1986). In the subsurface the Big Clifty Formation ranges in thickness from 40 to 100 ft (12.2 to 30.5 m) (Droste and Keller, 1995).
The formation conformably overlies the Beech Creek Limestone and is overlain conformably by the Haney Limestone or disconformably by the Mansfield Formation (Pennsylvanian) (Gray, 1986).
The Big Clifty Formation of Indiana usage is equivalent to the Fraileys Shale of the standard Chesterian section, but in Illinois the term “Big Clifty” is applied to a sandstone member of the Fraileys Shale (Swann, 1963; Atherton and others, 1975, p. 156-157; Gray, 1986).
Regional Indiana usage:
Illinois Basin (COSUNA 11)
Cypress Sandstone, Jackson Sand
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.
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.
Butts, Charles, 1917, Mississippian formations of western Kentucky: Descriptions and correlations of the Mississippian formations of western Kentucky: Kentucky Geological Survey, ser. 4, v. 5, pt. 1, 119 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.
Gray, H. H., 1970, Big Clifty Formation, 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. 14-15.
Gray, H. H., 1986, Big Clifty Formation, 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. 13-14.
Gray, H. H., Dawson, T. A., McGregor, D. J., Perry, T. G., and Wayne, W. J., 1957, Rocks associated with the Mississippian-Pennsylvanian unconformity in southwestern Indiana: Indiana Geological Survey Field Conference Guidebook 9, 42 p.
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.
Malott, C. A., 1931, Geologic structure in the Indian and Trinity Springs locality, Martin County, Indiana: Indiana Academy of Science Proceedings, v. 40, p. 217-231.
Malott, C. A., 1952, Stratigraphy of the Ste. Genevieve and Chester formations of southern Indiana: Ann Arbor, Michigan, Edwards Letter Shop, 105 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.
Norwood, C. J., 1876, Report on the geology of the region adjacent to the Louisville, Paducah, and Southwestern Railroad: Kentucky Geological Survey Report of Progress 1, new ser., p. 355-448.
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.
Welch, J. R., 1978, Pterotocrinus rugosus Lyon & Casseday from the middle Chesterian of the Illinois Basin: Journal of Paleontology, v. 52. p. 904-915.
For additional information, contact:
Nancy Hasenmueller (email@example.com)Date last revised: June 8, 2017