ammonites
Tyrone A section (Ordovician of the United States)

Also known as USGS collection 4073-CO, Milner, KY

Where: Woodford County, Kentucky (38.0° N, 84.8° W: paleocoordinates 27.2° S, 63.3° W)

• coordinate based on nearby landmark

• hand sample-level geographic resolution

When: Grier Limestone Member (Lexington Limestone Formation), Shermanian (460.9 - 449.5 Ma)

• "Grier Limestone Member, Lexington Limestone [...] 148 ft above the base of the Curdsville Limestone Member, Lexington Limestone."

• bed-level stratigraphic resolution

Environment/lithology: open shallow subtidal; coarse-grained, nodular, shelly/skeletal limestone and fine-grained, nodular, shelly/skeletal, argillaceous limestone

• "Cressman (1973) inferred that the Grier Limestone Member was deposited under shallow-water (less than 50 ft deep), well-aerated, but normally low energy subtidal marine conditions."
• " [...] 100-180 ft of thin, irregularly bedded, often nodular, very fossiliferous limestone. These limestones contain a diverse marine fauna of brachiopods, bryozoans, and crinoids in coarser grained lithologies and ostracodes, univalved mollusks, and pelecypods in finer grained, more argillaceous lithologies."

Size class: macrofossils

Preservation: replaced with silica

Reposited in the USNM

Collection methods: bulk, acetic,

• " [...] specimens were obtained from bulk rock collections (36,000 pounds (lbs) of limestone) made by USGS field parties in the 1960's and 1970's." This statement not only applies to the Tyrone A locality. For further details on collection methods see p. P22 in the primary reference

Primary reference: R. C. Frey. 1995. Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati Arch region of Kentucky, Indiana, and Ohio. U.S. Geological Survey Professional Paper 1066P:1-126 [S. Holland/S. Holland] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 87818: authorized by Björn Kröger, entered by Torsten Liebrecht on 25.03.2009