Historical:Dutch Creek Sandstone Member
Charles Collinson and Elwood Atherton
The Dutch Creek Sandstone Member of the Grand Tower Limestone (Savage, 1920, p. 170-171, 175; Meents and Swann, 1965, p. 6) is named for Dutch Creek, a tributary of Clear Creek in central Union County.
The Dutch Creek Sandstone Member has no designated type section. An exposure along a secondary road 1.1 miles northwest of its junction with Illinois Highway 127 (W 1/2 NW 27, 11S-2W), about 2 miles north of Dutch Creek, has been used as a reference section (Meents and Swann, 1965).
The Dutch Creek was originally called the Oriskany Sandstone by Worthen (1866).
Extent and Thickness
The Dutch Creek is exposed at many localities in Union, Alexander, and Jackson Counties (Weller and Ekblaw, 1940), and it is present in subsurface at many places throughout the area of the Grand Tower Limestone. However, the principal occurrences are in the outcrop area and in Wayne and adjacent counties of eastern Illinois (Collinson et al., 1967a). The Dutch Creek is as much as 30 feet thick in the outcrop area but is more commonly less than 15 feet, in many areas only a foot or two thick.
At the reference section the gradation of the member to the overlying part of the Grand Tower and the unconformable contact on the underlying Clear Creek can be seen. Because of the discontinuous nature of the sandstone and its lateral and vertical gradation to sandy dolomite or limestone, Meents and Swann (1965) restricted the Dutch Creek to localities where beds of sandstone are present and classified it as a member of the Grand Tower Limestone.
The Dutch Creek is a fossiliferous, calcareous sandstone composed of well rounded, well sorted, medium to fine quartz grains. In many areas the sandstone is interbedded with sandy limestone.
The abundant fauna is principally brachiopods and corals. The fossil mold of the coral Pleurodictyum problematicum is an especially distinctive indicator of the member. Prominent brachiopods include Amphigenia curta, Rhipidomella cf. R. penelope, and Protoleptostrophia perplana.
COLLINSON, CHARLES, L. E. BECKER, G. W. JAMES, J. W. KOENIG, and D. H. SWANN, 1967a, Illinois Basin, in International symposium on the Devonian System: Alberta Society of Petroleum Geologists, v. 1, p. 940-962; Illinois State Geological Survey Reprint 1968-G.
MEENTS, W. F., and D. H. SWANN, 1965, Grand Tower Limestone (Devonian) of southern Illinois: Illinois State Geological Survey Circular 389, 34 p.
SAVAGE, T. E., 1920, Devonian formations of Illinois: American Journal of Science, v. 49, p. 169-182.
WELLER, J. M., and G. E. EKBLAW, 1940, Preliminary geologic map of parts of the Alto Pass, Jonesboro, and Thebes Quadrangles, Union, Alexander, and Jackson Counties: Illinois State Geological Survey Report of Investigations 70, 26 p.
WORTHEN, A. H., 1866, Geology: Geological Survey of Illinois, v. 1, 504 p.
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