La Salle Limestone Member
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
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