Monday, March 30, 2009

Silurian Chain Coral Called Halysites

Here is a Silurian index fossil called Halysites or chain coral. It is part of the hands on exhibit in the Discovery Gallery at the Louisville Science Center where I volunteer. The specimen does not have a label as to where it is from but it looks like ones I find in the area so it could be from Jefferson or Clark counties in this area.

I found a description of this coral in a a book stored at entitled "An Introduction to the Study of Fossils (Plants and Animals) by Hervey Woodburn Shimer published in 1914. From pages 137-138, "Coral compound, composed of long, laterally compressed corallites, and covered by peritheca. Septa absent or represented by spines; tabulae numerous. Between each pair of corallites is a small tube. Budding occurs only from one side and the young corallites remain in contact with the parent by a constricted edge, thus forming chains, in which each corallite is a link (whence the common name, "chain-coral," from the Greek halysis, chain)."


Dave said...

I love that specimen, very good definition of the corralites. I've never found one in the Sulurian rocks in my area but have always wanted a specimen. Will have to wait until I get out to your area maybe. :)

Fossil Detective said...

That specimen is a little damaged which can happen being a hands on fossil.

There is a really nice specimen across the Ohio River in Clarksville, Indiana at the Falls of the Ohio State Park Center. There is a picture of it at the KYANA Geological Society site ( in the Silurian fossils section.

If you are planning to visit the Louisville area, drop us a message at the KYANA site. Our meetings are open to visitors.