T. C. Buschbach
The Jordan Sandstone is named for Jordan, Scott County, Minnesota, where it is exposed in quarries and outcrops along Sand Creek (N.H. Winchell, 1874, p. 149).
Extent and Thickness
The Jordan Sandstone is not exposed in Illinois but is a few to 75 feet thick in wells in Jo Daviess and Carroll Counties.
The Jordan Sandstone (A. Winchell, 1872), is the uppermost Cambrian formation in the extreme northwestern part of Illinois. In exposures along the Mississippi River a short distance northwest of Illinois in Iowa, Minnesota, and Wisconsin, the formation is a white to yellowish gray, partly iron-stained sandstone that is medium to fine grained at its base. In some places the upper part is coarse to very coarse grained (Stauffer and Thiel, 1941). It varies from thin to thick bedded. Cross bedding is common. East and south of Jo Daviess and Carroll Counties the Jordan Sandstone grades laterally to the Eminence Formation.
Fossils are abundant in some beds in the outcrop area of the Jordan Sandstone.
STAUFFER, C. R., and G. A. THIEL, 1941, Paleozoic and related rocks of southeastern Minnesota: Minnesota Geological Survey Bulletin 29, 261 p.
WINCHELL, ALEXANDER, 1872, Report of a geological survey of the vicinity of Belleplaine, Scott County, Minnesota: St. Paul, Minnesota, 16 p.
WINCHELL, N. H., 1874, Second annual report for the year 1873: Minnesota Geological and Natural History Survey, p. 73-219.
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