Prospect Hill Siltstone

Lithostratigraphy: Mammoth Cave Limestone Megagroup >>North Hill Group >>Prospect Hill Siltstone
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Kinderhookian Series
Allostratigraphy: Kaskaskia 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)

Elwood Atherton, Charles Collinson, and Jerry A. Lineback

Name

Original description

Prospect Hill Siltstone (Moore, 1928, p. 20; Workman and Gillette, 1956, p. 30).

Derivation

Named for Prospect Hill, near Burlington, Iowa.

Other names

History/background

Originally designated a member of the Hannibal Formation, but Workman and Gillette (1956) differentiated the uppermost beds as the Starrs Cave Formation and made the Prospect Hill a formation in the North Hill Group.

Type section

Type location

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The Prospect Hill Siltstone is conformable with the underlying McCraney and the overlying Starrs Cave, but where the latter is absent it is overlain unconformably by the Burlington Limestone.

Extent and thickness

The Prospect Hill Siltstone occurs in extreme western Illinois within the area underlain by the McCraney Limestone (fig. M-9). It has a maximum thickness of 29 feet but thins eastward to its boundary. It is exposed above the McCraney along Fall Creek in southern Adams County (SE 23, 3S-8W).

Fig. M-9 -- Thickness of Chouteau Limestone and areal extent of formations of the North Hill Group (after Buschback, 1952; Workman and Gillete, 1956).

Lithology

The siltstone is light gray to buff, calcareous, pyritic, massive, and friable.

Core(s)

Photograph(s)

Contacts

Well log characteristics

Fossils

The Prospect Hill contains few macrofossils, however, conodonts are abundant.

Age and correlation

The abundant conodonts in the Prospect Hill show a close correlation with the upper part of the Chouteau Limestone (Collinson, 1961, 1964).

Environments of deposition

Economic importance

Remarks

References

COLLINSON, CHARLES, 1961, Kinderhookian Series in the Mississippi Valley, in Northeastern Missouri and west-central Illinois: Kansas Geological Society Guidebook, 26th Annual Field Conference, Missouri Geological Survey Report of Investigations 27, p. 100-109; Illinois State Geological Survey Reprint 1961-U.
COLLINSON, CHARLES, 1964, Western Illinois: 28th Annual Tri-State Field Conference, Quincy, Illinois, Illinois State Geological Survey Guidebook Series 6, 30 p.
MOORE, R. C., 1928, Early Mississippian formations in Missouri: Missouri Bureau of Geology and Mines, v. 21, 283 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.

ISGS Codes

Stratigraphic Code	Geo Unit Designation
5460	--