USGS 6128-CO. Pond west of Mt. Horeb and Carrick Road interesction (Ordovician of the United States)

Where: Scott County, Kentucky (38.2° N, 84.4° W: paleocoordinates 26.8° S, 59.8° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Clays Ferry Formation, Katian (453.0 - 445.2 Ma)

• "Toungue of Clays Ferry Formation between underlying Millersburg Member, Lexington Limestone, and overlying Tanglewood Limestone Member, Lexington Limestone.

•5-10 ft above base of Clays Ferry Formation tongue, 15-20 ft above Allonychia flanaganesis zone in Millersburg Memeber."

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, shelly/skeletal, gray limestone and lithified, gray, green shale

• "This 120 to 220 ft of interbedded limestone and shale straddles the Middle-Upper Ordovician boundary. To the south it intertongues with the upper members of the Lexington Limestone, but to the north it becomes younger and intertongues with the shales of the Kope Formation in north-central Kentucky.

•Limestone makes up 30 to 60 percent of the Clays Ferry Formation. Beds are even and 1 to 6 in thick. The limestone varies from medium- to dark-gray, argillaceous calcisiltite to medium-gray brachiopodal limestone to medium-gray crinoidal calcarenite. The calcisiltite is sparsely fossiliferous and contains mainly crinoidal fragments and some gastropods. The brachiopoal limestone is characterized by abundant Rafinesquina, some of which are shingled, as well as by Sowerbyella and Dalmanella, all packed in a mud matrix. Bryozoans are also common.

•Shale makes up 30 to 60 percent of the formation. It is generally greenish to olive gray, and is present in distinctly laminated sets 1 to 12 in thick. Fossils generally are sparse in these shales, though bryozoans are common at some locations.

•Siltstone makes up 5 to 10 percent of the unit, occurring mainly in the upper part. It is present mostly in 1- to 3-in even beds in which fossils are sparse. This lithology resembles the Garrard Siltstone, which overlies the Clays Ferry in south-central Kentucky."

Size classes: macrofossils, mesofossils

Preservation: replaced with silica

Reposited in the USNM

Primary reference: G.P. Wahlman. 1992. Middle and Upper Ordovician symmetrical univalved mollusks (Monoplacophora and Bellerophontina) of the Cincinnati Arch region. United States Geological Survey Professional Paper 1066(O):1-123 [P. Wagner/P. Wagner/E. Ito]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 100175: authorized by Pete Wagner, entered by Hallie Street on 01.12.2010, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Rhynchonellata
 Orthida - Platystrophiidae
Platystrophia colbiensis
Gastropoda
 Bellerophontida - Bellerophontidae
"Sphenosphaera clausus" = Sphenosphaera rogersensis
"Sphenosphaera clausus" = Sphenosphaera rogersensis Foerste 1914 snail