GEOLEX

Summary of Citation: Dutchtown

Publication:
Nelson, W.J., Devera, J.A. and Masters, J.M., 1996, Geology of
   the Jonesboro 15-minute quadrangle, southwestern Illinois;
   Jonesboro, Mill Creek, Ware, and McClure 7.5-minute quadrangle:
   Illinois Geological Survey Bulletin, no. 101, 57 p., Also,
   1995, Illinois Geological Survey Geologic Quadrangle Map,
   IGQ-14, scale 1:24,000.

Usage in Publication:
Dutchtown Formation

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Illinois basin Ozark uplift

Summary:
Ordovician (Mohawkian) Dutchtown Formation is about 200 ft thick in Ohio Oil Co. No. 1 Cross well, NW1/4NW1/4NE1/4 sec. 21, T13S, R2W, Jonesboro 7.5-min quad and 361 ft thick in Humble Oil Co. No. 1 Pickel well, NW1/4SE1/4NW1/4 sec. 21, T13S, R2W, Mill Creek 7.5-min quad. Thins northward to 185 ft in Cape Girardeau Co., MO, and pinches out in Perry Co., MO. Consists of dark-colored micritic to finely crystalline limestone, in addition to argillaceous and partly sandy dolomite.

Summary of Citation: Dutchtown

Publication:
Nelson, W.J., 1996, Bedrock geology of the Paducah 1 degrees x
   2 degrees quadrangle, Illinois, Kentucky, and Missouri:
   Illinois Geological Survey Bulletin, no. 102, 40 p., (incl.
   geologic map, scale 1:100,000)

Usage in Publication:
Dutchtown Formation

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Illinois basin Ozark uplift Upper Mississippi embayment

Summary:
Ordovician (Champlainian) Dutchtown Formation is relatively thin and combined with overlying Joachim Dolomite on geologic map. Crops out immediately east of St. Peter Sandstone, along a faulted strip that runs south-southeast through Perry and Cape Girardeau Cos., MO. Consists of medium- to very dark-gray and brownish-gray, very fine- to fine-grained, silty to sandy carbonate rock, most of which is dolomite; limestone becomes important constituent to the south. Fossils include pelecypods, gastropods, brachiopods, ostracods, and conodonts. Cryptozoan reefs occur near middle of Dutchtown in Thebes and Scott City 7.5-min quads. Also includes thin beds of brown, fine-grained, dolomitic sandstone and greenish-gray shale. Thins northward from 185 ft in southern Cape Girardeau Co to 20 ft or less in northern Cape Girardeau and Perry Cos. Contact with underlying St. Peter is disconformable according to quad mappers in MO; Templeton and Willman (1963) report contact to be gradational north of Cape Girardeau.

Summary of Citation: Dutchtown

Publication:
Nelson, W.J., 1998, Bedrock geology of the Paducah 1 degrees x
   2 degrees CUSMAP quadrangle, Illinois, Kentucky, and Missouri,
   IN The Paducah CUSMAP quadrangle, resource and topographical
   investigations: U.S. Geological Survey Bulletin, 2150-B, p.
   B1-B36, (incl. geologic map, scale 1:100,000)

Usage in Publication:
Dutchtown Formation*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Ozark uplift

Summary:
Ordovician (Mohawkian) Dutchtown Formation thins northward from Cape Girardeau Co. to Perry Co., MO.

Summary of Citation: Dutchtown

Publication:
Harrison, R.W., in press, Geologic map of the Thebes quadrangle,
   Missouri and Illinois: U.S. Geological Survey Geologic
   Quadrangle Map, GQ-__, scale 1:24,000

Usage in Publication:
Dutchtown Formation*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Illinois basin Upper Mississippi embayment

Summary:
Middle Ordovician (Mohawkian) Dutchtown Formation is mapped undivided with Joachim Dolomite in subsurface of Upper Mississippi embayment in MO and Illinois basin in IL.