Type section: The name “Jacobs Chapel Shale” was applied by Campbell (1946, p. 855-856) to less than 1 ft (0.3 m) of greenish plastic shale overlying black shale of the New Albany Shale and underlying the Rockford Limestone in southern Indiana (Rexroad, 1970, 1986). The best exposure in the area near Jacobs Chapel Church and School is about 0.75 miles (1.2 km) northwest of Jacobs Chapel Church in the banks of Lewis Branch on the line between lots 86 and 107, Clark's Grant, Floyd County, Indiana (Rexroad, 1970, 1986).
History of usage:
The Jacobs Chapel is now recognized as the uppermost bed of the Clegg Creek Member (Lineback, 1968, 1970) and of the Ellsworth Member (Hasenmueller and Bassett, 1981) of the New Albany Shale (Rexroad, 1986).
The Jacobs Chapel is a plastic greenish to dark-green glauconitic, sparsely fossiliferous shale. It is similar to some shale beds lower in the New Albany but contains more glauconite and calcite, so that earlier the Jacobs Chapel was interpreted as a basal phase of the Rockford Limestone (for example, Huddle, 1934; Rexroad, 1970, 1986).
Rexroad (1986) noted that the abrupt lithologic changes at both the top and the bottom of the Jacobs Chapel Bed suggested brief hiatuses.
The Jacobs Chapel Bed belongs in the Kinderhookian Series and correlates with part of the Hannibal Shale of the Mississippi Valley (Rexroad, 1986). It also correlates within the lower part of the Coldwater Shale of northern Indiana and adjacent Michigan (Rexroad, 1986). The conodonts are only slightly older than those of the Siphonodella isoticha-S. cooperi Assemblage Zone in the overlying Rockford Limestone, but a precise correlation with the Mississippi Valley standards is not feasible (Rexroad, 1969; Rexroad, 1986).
Regional Indiana usage:
Illinois Basin Margin (COSUNA 12)
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.)
Campbell, Guy, 1946, New Albany Shale: Geological Society of America Bulletin, v. 57, p. 829-908.
Cluff, R. M., Reinbold, M. L., and Lineback, J. A., 1981, The New Albany Shale Group of Illinois: Illinois State Geological Survey Circular 518, 83 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.
Hasenmueller, N. R., and Bassett, J. L., 1981, Stratigraphy, in Hasenmueller, N. R., and Woodard, G. S., eds., Studies of the New Albany Shale (Devonian and Mississippian) and equivalent strata in Indiana: Indiana Geological Survey, p. 5-32.
Huddle, J. W., 1934, Conodonts from the New Albany Shale of Indiana: Bulletins of American Paleontology, v. 21, no. 72, 136 p.
Lineback, J. A., 1968, Subdivisions and depositional environments of New Albany Shale (Devonian-Mississippian) in Indiana: American Association of Petroleum Geologists Bulletin, v. 52, p. 1,291-1,303.
Rexroad, C. B., 1970, Jacobs Chapel Bed, 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. 76.
Rexroad, C. B., 1986, Jacobs Chapel 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. 63-64.
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.
For additional information contact:
Nancy Hasenmueller (email@example.com)Date last revised: November 30, 2016