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 books.google.com 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)."

Club Moss Root Fossil at Louisville Science Center

Here is a specimen from the Discovery Gallery hands on fossil exhibit at the Louisville Science Center. It is labeled as a 'Club Moss Root' but no location or time period included. I do not know much about fossilized plants but most of the fossils I have seen are from the Mississippian or Pennsylvanian periods (Carboniferous).

Research at this site about club mosses they were known as lycophytes of the genus Lycopodium (lycos Greek for wolf and pous Greek for foot).

I did not have a ruler but the specimen seemed to be about 15 cm long and 6 cm in diameter.

Trilobite at Louisville Science Center - Elrathia kingii?

Here are a series of pictures taken of an imprint(?) of trilobite in the hands on activities in the Discovery Gallery of the Louisville Science Center. This trilobite does not look like anything I have found in the Louisville, Kentucky or southern Indiana area. Also I first thought the blackish rock was some sort of coal but after examining it seems pretty hard. The last picture shows the cut marks of probably a diamond circular saw blade.

Since it was an unknown trilobite to me I consulted the BEST trilobite fossil site on the internet Sam Gon III's http://www.trilobites.info/. It appears to me after looking at his drawings and images on the site, this speciment might be an Elrathia kingii. Specifically, the site lists it as Order: Ptychopariida, Suborder: Ptychopariina, Superfamily: Ptychoparioides, Family: Ptychopariidae. The site has a picture gallery with references to pictures on another site http://www.trilobite.com/ which sells Elrathia kingii trilobites that lived during the Middle Cambian in Utah. Also I believe it or another site noted that this trilobite is the most common one sold today that is intact.



Click on pictures to view larger version.



Part of the pygidium is missing. I count 12 thorax segments.

Bottom of plate that contains the trilobite. Rock is almost black to very dark gray in color.

Side of rock plate containing trilobite with maybe diamond blade cut marks. This specimen could have been part of a large group and was sold as an individual piece. If I had to guess, the trilobite size is about 3 cm long and 2 cm wide.