La Salle Limestone Member

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Lithostratigraphy: McLeansboro Group >>Bond Formation >>La Salle Limestone Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Missourian Series
Allostratigraphy: Absaroka Sequence

Primary source

Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.

Contributing author(s)

M. E. Hopkins and J. A. Simon

Name

Original description

The La Salle Limestone Member of the Bond Formation (Cady, 1908, p. 128-134).

Derivation

Named for La Salle, La Salle County.

Other names

History/background

Type section

Type location

The type section consists of exposures near Bailey's Falls, south of La Salle (14, 33N-1E) (Wanless, 1956, p. 12).

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The base of the La Salle Limestone Member is the base of the Bond Formation in northern Illinois.

Extent and thickness

The La Salle Limestone is well developed in northern Illinois, where it has been quarried extensively (Cady, 1919b). It is as much as 30 feet thick in exposures near La Salle along the west flank of the La Salle Anticline, but it thins westward to about 12 feet west of Spring Valley, Bureau County.

Lithology

In a belt 1-2 miles wide along its eastern margin, it is a fine-grained, thick-bedded, light gray, nodular limestone containing a few shale partings and a large and diverse marine fauna, mainly brachiopods and gastropods. It grades westward to a fine-grained, argillaceous, tan, brown-weathering limestone that occurs mostly in even beds 4-8 inches thick separated by strong shale partings and containing a restricted marine fauna characterized by large brachiopods, mostly productids.

Core(s)

Photograph(s)

Contacts

Well log characteristics

Fossils

Age and correlation

It formerly was correlated with the Millersville and Livingston Limestone Members but is now correlated with the Shoal Creek Limestone.

Environments of deposition

Economic importance

Remarks

References

CADY, G. H., 1908, Cement making materials in the vicinity of La Salle, in Year-Book for 1907: Illinois State Geological Survey Bulletin 8, p.127-134.
CADY, G. H., 1919b, Geology and mineral resources of the Hennepin and La Salle Quadrangles: Illinois State Geological Survey Bulletin 37, 136 p.
WANLESS, H. R., 1956, Classification of the Pennsylvanian rocks of Illinois as of 1956: Illinois State Geological Survey Circular 217, 14 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation
2090
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