The Silurian Period spanned approximately 438–408 million years ago during the Paleozoic Era. It was named by British geologist Roderick Murchison in 1835 after an ancient Celtic tribe, the Silures. In the Louisville area, Silurian fossils occur in a series of formations, from oldest to youngest: Lower Silurian (Llandoverian) – Brassfield Formation (dolostone); and Middle Silurian (Wenlockian) – Osgood Formation (mostly fossil-poor shale), Laurel Formation (dolostone), Waldron Shale (dolomitized in Louisville but unaltered in parts of Clark Co., IN), and the Louisville Limestone (locally somewhat dolomitized). Much of the Silurian rock in the Louisville area is approximately 425 million years old.

For more information on Silurian corals of this region, see Kentucky Fossil Corals of the Silurian and Devonian Rocks of Kentucky by William J. Davis, available here: http://www.uky.edu/OtherOrgs/KPS/fossilcorals/index.htm .

The Kentucky Paleontological Society also hosts A Monograph of the Fossil Shells of the Silurian and Devonian Rocks of Kentucky by Henry Nettelroth, available here: http://www.uky.edu/OtherOrgs/KPS/books/nettelroth/nettelroth.htm .

Another useful classic reference is Paleontology Fossil Corals by Dr. C. Rominger (1876), available here: http://www.archive.org/stream/palontologyfos00romi .

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Brachiopods

• Eospirifer radiata (Hall), Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN – Falls of the Ohio State Park collection
• Fardenia subplana (Hall), Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN
• Lingulid inarticulate brachiopod , Waldron Shale, Clark Co., IN
• Meristella maria (Hall), Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN – Falls of the Ohio State Park collection
• Pentamerus sp. , Silurian, KY
• Stegerhynchus sp. , mass mortality bed with Eospirifer eudora (Hall) at the bottom, Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN – Falls of the Ohio State Park collection
• Whitfieldella nitida (Hall), Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN – Falls of the Ohio State Park collection

Bryozoans (Moss Animals)

• Pyrite-encrusted fenestrate bryozoans , Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN – Falls of the Ohio State Park collection

Cephalopods (Mollusca)

• Cyrtocone cephalopod , Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN
• Dawsonceras amycus (Hall), Jeffersonville, Clark Co., IN
• Dawsonceras annulatus (Sowerby), Louisville, Jefferson Co., KY

Clams (Pelecypods / Mollusca)

• Cypricardina arata (Hall), Middle Silurian, Louisville Limestone, Oldham Co., KY
• Pterinea brissa Hall, Middle Silurian, Waldron Shale, Jeffersonville, Clark Co., IN – Falls of the Ohio State Park collection

Corals (Cnidaria)

• Alveolites fibrosus Davis, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Astrocerium venustum Hall, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Coenites menis (Davis), Middle Silurian, Louisville Limestone, Oldham Co., KY
• Coenites reticulata (Hall), Middle Silurian, Louisville Limestone, Oldham Co., KY
• Coenites reticulata (Hall), also referred to as Cladopora reticulata, Middle Silurian, Louisville Limestone, Jefferson Co., KY
• Favosites cristatus Davis, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Favosites niagarensis Hall, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Halysites louisvillensis Stumm, Louisville Limestone, Louisville, Jefferson Co., KY
• Halysites sp. , Middle Silurian, Louisville Limestone, Louisville, Jefferson Co., KY (large colony collected in the 1880s; Falls of the Ohio State Park collection)
• Heliolites romingeri Stumm, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Heliolites subtubulatus (McCoy), colonial coral, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Plasmopora follis Edwards & Haime, Louisville Limestone, Jefferson Co., KY
• Propora papillata Edwards & Haime, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Thecia major Rominger, Middle Silurian, Louisville Limestone, Oldham Co., KY

Crinoids & Blastoids (Echinodermata)

• Caryocrinites ornatus (Say), Louisville Limestone, Utica, Clark Co., IN
• Eucalyptocrinites-type crinoid holdfast on Astrocerium venustum Hall, Middle Silurian, Louisville Limestone, Oldham Co., KY
• Eucalyptocrinites crassus calyx, Waldron Shale, St. Paul, Decatur Co., IN
• Eucalyptocrinites ovalis calyx, Middle Silurian, Louisville Limestone, Jefferson Co., KY
• Eucalyptocrinites-type crinoid holdfast , Waldron Shale, St. Paul, Shelby Co., IN
• Lyriocrinus melissa (Hall), Middle Silurian, Waldron Shale, Clark Co., IN – Falls of the Ohio State Park collection
• Myelodactylus sp. , a coiled crinoid (calyx in the center, not exposed), Middle Silurian, Waldron Shale, Clark Co., IN
• Troosticrinus reinwardti (Troost), Brownsport Group, Decatur Co., TN
• Unidentified crinoid holdfast , Waldron Shale, St. Paul, Shelby Co., IN

Snails (Gastropoda / Mollusca)

• Platyceras (Platystoma) niagarense (Hall), Middle Silurian, Waldron Shale, Oldham Co., KY

Sponges (Porifera)

• Astraeospongia meniscus (Roemer), Bob Formation, Decatur Co., TN
• Unidentified stromatoporoid , highly conical colony, Middle Silurian, Louisville Limestone, Oldham Co., KY

Trilobites (Arthropoda)

• Arctinurus occidentalis (Hall), pygidium, Waldron Shale, Clark Co., IN
• Bumastus sp. , pygidia, Middle Silurian, Laurel Formation, Bardstown, Nelson Co., KY
• Calymene breviceps Hall, Waldron Shale, Decatur Co., IN
• Calymene breviceps Hall, Waldron Shale, Hartsville, Bartholomew Co., IN
• Dalmanites sp. , imprint of partial pygidium and thorax, Louisville Limestone, Jefferson Co., KY
• Harpidella “Cyphaspis” christyi , Waldron Shale, Hartsville, Bartholomew Co., IN
• Sthenarocalymene celebra (Raymond), Middle Silurian, Springfield Formation, Wayne Co., IN
• Sthenarocalymene celebra (Raymond), Laurel Dolomite, Metamora, Franklin Co., IN
• Trimerus delphinocephalus (Green), Middle Silurian, Waldron Shale, Clark Co., IN
• Trimerus delphinocephalus , cephalon, Middle Silurian, Waldron Shale, Clark Co., IN
• Trimerus delphinocephalus , thorax/pygidium, Middle Silurian, Waldron Shale, Clark Co., IN

Other Fossils

• Graptolite Dictyonema sp. , Middle Silurian, Waldron Shale, Clark Co., IN

A Note About Fossil Names

Fossils are named like other biological species. The genus and trivial name (for example, Auloceras + undulata) together form the species name. The author’s name is placed in parentheses (for example, “(Billings)”) if the genus has changed since the original description; it is not in parentheses if the genus is the original designation, as in Favosites niagarensis Hall.

A subgenus may be written as Favosites (Emmonsia) emmonsi Rominger, where Emmonsia is the subgenus. It was originally described as its own genus but has since been folded back into Favosites. If the species name is not known, “sp.” is used after the genus name (for example, Cyclonema sp.).

Names of fossils often change as research progresses. We strive to use the most up-to-date names available for the specimens illustrated on this site.

Abbreviations

Common abbreviations used in locality information include: Co. for County, KY for Kentucky, IN for Indiana, OH for Ohio, and TN for Tennessee.

Fossil drawings © Michael Popp, 2009.