Historical:Glen Park Formation
Elwood Atherton, Charles Collinson, and Jerry A. Lineback
The "Glen Park" Formation (Ulrich, 1904, p. 110; Moore, 1928, p. 138-140) is named for Glen Park Station about 25 miles south of St. Louis, Jefferson County, Missouri.
The type section of the "Glen Park" Formation is located near Glen Park Station, where 1.4 feet of fossiliferous oolitic limestone was named Glen Park.
Stuart Weller (1914, p. 464-467) gave the name "Hamburg Oolite" to exposures of the oolitic limestone at Hamburg that he considered to be younger than the type Glen Park, but the name was preempted and Moore (1928) redefined the name "Glen Park" to include the strata at Hamburg. However, studies of the conodonts indicate that the two units are not of the same age- the type Glen Park being Devonian and the Hamburg strata Mississippian- but the name "Glen Park" has been retained pending introduction of a new name.
Extent and Thickness
The "Glen Park" is exposed in and near the Mississippi River bluffs in Calhoun, Pike, and Jersey Counties, and in the lower Illinois Valley in Calhoun and Jersey Counties. It is restricted to western Illinois where its thickness varies greatly but does not exceed 25 feet in the outcrop area. Much of the thick brown shale included in the "Glen Park" by Workman and Gillette (1956) is now included in the Hannibal Shale.
The "Glen Park" rests with apparent erosional contact on the Louisiana Limestone, or on the Saverton Shale where the Louisiana is not present. However, no unconformity is generally recognizable where the "Glen Park" is absent.
The lithology of the "Glen Park" varies considerably and may be almost any combination of sandy, silty, brown or buff limestone, buff siltstone, silty shale, oolitic limestone, limestone conglomerate, or thin sandstone beds. In Gresham Hollow, about a mile southeast of Hamburg, Calhoun County (NW 1 , 10S-3W), it consists of calcareous, blue-gray siltstone overlying light gray to buff, silty, dense, fine-grained limestone. The limestone contains beds of dolomitic siltstone bearing Tasmanites and also lenses of highly fossiliferous, white to buff, conglomeratic, oolitic, cross-bedded limestone. Stuart Weller (1906b) described the fauna.
MOORE, R. C., 1928, Early Mississippian formations in Missouri: Missouri Bureau of Geology and Mines, v. 21, 283 p.
ULRICH, E. O., 1904, in E. R. Buckley and H. A. Buehler, Quarrying industry of Missouri: Missouri Bureau of Geology And Mines, v. 2, 371 p.
WELLER, STUART, 1906b, Kinderhook faunal studies--4. Fauna of the Glen Park limestone: St. Louis Academy of Science Transactions, v. 16, p. 435-471.
WELLER, STUART, 1914, Mississippian Brachiopoda of the Mississippi Valley Basin: Illinois State Geological Survey Monograph I, part I, 508 p.; part 2, 187 p.
WORKMAN, L. E., and TRACEY GILLETTE, 1956, Subsurface stratigraphy of the Kinderhook Series in Illinois: Illinois State Geological Survey Report of Investigations 189, 46 p.
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