Type locality: The unit is exposed in the Ditney Hills in Warrick County, Indiana (secs. 4, 5, and 6, T. 5 S., R. 9 W.) (Wier, 1970, 1986).
History of usage:
The name "Ditney Formation" was first used by Fuller and Ashley (1902, p. 2) for the rocks between the Somerville Limestone (now the West Franklin Limestone Member of the Shelburn Formation) and the Inglefield Sandstone Member in an exposure that included 20 ft (6 m) of shale, thin sandstone, and thin coal in the Ditney Hills in Warrick County, Indiana (secs. 4, 5, and 6, T. 5 S., R. 9 W.) (Wier, 1970, 1986). These rocks were assigned to the Patoka Formation (Wier, unpublished manuscripts and 1970, p. 48), but the name "Ditney" was retained for the coal that was called the Ditney Coal by Fuller and Ashley (1902, p. 2) (Wier, 1970, 1986).
The Ditney Coal Member, a banded, partly shaly coal, is generally less than a foot (<0.3 m) thick. It is separated from the underlying West Franklin Limestone Member by 1 to 20 ft (0.3 to 6 m) of unnamed gray shale and underclay (Wier, 1970, 1986).
The Ditney Coal Member is equivalent to the Chapel (No. 8) Coal Member in Illinois (Weir, unpublished manuscripts and 1970).
Regional Indiana usage:
Illinois Basin (COSUNA 11)
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.)
Fuller, M. L., and Ashley, G. H., 1902, Description of the Ditney quadrangle: U.S. Geological Survey Geologic Atlas, Folio 84, 8 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.
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.
Wier, C. E., 1970, Ditney Coal Member, 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. 48-49.
Wier, C. E., 1986, Ditney Coal Member, 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. 38.
For additional information contact:
Nancy Hasenmueller (email@example.com)Date last revised: November 22, 2016