Water main layering, Dubuque and South Fifth Avenue, Stillwater (Ordovician of the United States)

Where: Minnesota (45.1° N, 92.8° W: paleocoordinates 19.4° S, 70.4° W)

• outcrop-level geographic resolution

When: Shakopee Formation, Cassinian (482.3 - 470.0 Ma)

• bed-level stratigraphic resolution

Environment/lithology: lithified, dolomitic, gray limestone

• Cryptozoon reefs are common in the Shakopee formation, and may be either thick lenticular masses which grade off laterally into beds of brecciated cryptozoon fragments or wide spread algal beds of relativesly uniform thickness. The associated shaly beds may show well-developed muc cracks with sand filling, and occasionally even ripple-marks appear among these local evidences of shallow water deposition. Over large areas the Shakopee appears as a massive gray to drab dolomite; more often, however, the thinner bedded Shakopee is really a dolomitic limestone whihc may be highly oolitic in the lower part of the formation and my contain large masses of oolitic chert.

Size class: macrofossils

Preservation: replaced with dolomite, replaced with silica

Primary reference: C. R. Stauffer. 1937. Mollusca from the Shakopee Dolomite (Ordovician) at Stillwater Minnesota. Journal of Paleontology 11(1):61-68 [P. Wagner/P. Wagner]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 56645: authorized by Pete Wagner, entered by Pete Wagner on 21.11.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Cephalopoda
 Ellesmerocerida - Protocycloceratidae
Cyptendoceras ruedemanni
Cyptendoceras ruedemanni Ulrich and Foerste 1936
 Ellesmerocerida - Rioceratidae
"Endoceras ? consuetum" = Rioceras consuetum
"Endoceras ? consuetum" = Rioceras consuetum Sardeson 1896
 Tarphycerida - Tarphyceratidae
Eurystomites kelloggi
Eurystomites kelloggi Whitfield 1886
 Endocerida - Endoceratidae
Cameroceras stillwaterense n. sp.
 Endocerida - Proterocameroceratidae
Cotteroceras compressum
Cotteroceras compressum Ulrich and Foerste 1936
Tergomya
 Tryblidiida - Tryblidiidae
Helcionopsis sp.
Helcionopsis sp. Ulrich and Scofield 1897
Gastropoda
 Murchisoniina - Hormotomidae
Hormotoma artemesia, Plethospira cassina
Hormotoma artemesia Billings 1865 snail
Plethospira cassina Whitfield 1886 snail
 Euomphalina - Raphistomatidae
"Ophileta canadensis" = Ceratopea canadensis
"Ophileta canadensis" = Ceratopea canadensis Billings 1865 snail
 Euomphalina - Ophiletidae
Ophileta sp.
Ophileta sp. Vanuxem 1842 snail