Type section: The Galesville Sandstone was named by Trowbridge and Atwater (1934, p. 45) for an exposure of 86 ft (26 m) of sandstone at Galesville, Wisconsin.
As traced to Indiana and described by Becker, Hreha, and Dawson (1978), the Galesville Sandstone in the subsurface of northwestern Indiana consists of fine- and coarse-grained sandstones (Droste and Patton, 1986). The Galesville and the Ironton Sandstones together range in thickness from about 100 ft (30 m) at the arbitrary cutoff with the Davis Formation to more than 200 ft (61 m) in the northwest corner of Indiana (Droste and Patton, 1986). In northern Lake and Porter Counties in northwestern Indiana where the Galesville and the Ironton can be distinguished separately, the Galesville averages 75 ft (23 m) in thickness (Becker, Hreha, and Dawson, 1978).
The Galesville Sandstone conformably overlies the Eau Claire Formation and grades upward into the Ironton Sandstone (Droste and Patton, 1986). In part of northwestern Indiana the Galesville and Ironton Sandstones cannot be easily distinguished from one another (Droste and Patton, 1986). Both of these sandstones grade laterally into the Davis Formation and are nomenclaturally separated from the Davis by an arbitrary cutoff in central northern and western Indiana (Droste and Patton, 1986).
The Galesville Sandstone is also recognized by this one name in Illinois and Wisconsin, and it is equivalent to the lower part of the Davis Formation in central and southern Indiana and eastern Missouri, to the lower part of the Elvins Formation in western Kentucky, and to the lower part of the Potosi Dolomite in that part of southwestern Indiana where the Davis Formation has been replaced laterally by the Potosi (Droste and Patton, 1985).
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.)
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.
Droste, J. B., and Patton, J. B., 1986, Galesville Sandstone, 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. 50.
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.
Trowbridge, A. C., and Atwater, G. I., 1934, Stratigraphic problems in the upper Mississippi Valley: Geological Society of America Bulletin, v. 45, p. 21-80.
For additional information, contact:
Nancy Hasenmueller (email@example.com)Date last revised: August 27, 2014