Tuesday, December 1, 2009

Ordovician Period Trilobites

Two trilobite fossils are shown in this entry. The first is an intact enrolled Flexicalymene sp. trilobite. It is probably Ordovician Period and found in Kentucky. Thanks to Mary Ann for letting me photograph it. I forgot to ask about how it became part of her collection.  With some air abrasion cleaning, this specimen could be look'in nice!

The second trilobite fossil is just a fragment.  It is an Isotelus sp. I recently found on a field trip to Franklin County, Kentucky.  The original find was just the back of the cephalon plate with a broken genial spine. Using a Dremel engraving tool, more of the cephalon was exposed and the eye appeared as well.  Unfortunately, my inexperience with the engraver caused some white scratch marks on the cephalon and the eye piece.

This fossil was found in Lexington Limestone and is from the Ordovician Period.  The particular trilobite is the official state fossil of Ohio.  It was awarded that distinction by the legislature in 1985.

The image shows a close up to where the genial spine once protruded off the cephalon.

Possibly, these creatures reached lengths to almost a meter.

Cretalamna Shark Teeth

UPDATE: Thanks to Lance Hall for a new identification of this fossil shark tooth.  It appears to be a Cretalamna instead of a Scapanorhynchus that I originally reported.  Go to Lance's great fossil site: http://northtexasfossils.com/

Teeth of the Cretalamna shark from the Upper Cretaceous Period. It was found in the Eagle Ford Group, Kamp Ranch Formation in Dallas County, Texas.
Thanks to Herb for the images.