Ordovician Flexicalymene Trilobite

I picked this rock up in one of the eastern Louisville, Kentucky road cuts that has Ordovician Period fossils. Originally, I was attracted to a conical shaped cephalopod mold looking rock. Once I picked it up, it had a small exposed area of a trilobite thorax. The ridges of the thorax had matrix in them so it seemed like a good idea to sand blast them clean.

I took it to my cousin and pointed out that a cephalon was partially visible and maybe a whole trilobite was there. So he sandblasted the rock for about 20 minutes and what a surprise. There were sections of three Flexicalymene trilobites there. The largest one is about 2 cm long.

This is a work in progress. More matrix needs to be removed to see if another cephalon exists. Notice the white marks on the rock made by the engraver tool.

Devonian Clam Modiomorpha concentrica

These pictures are of a Devonian Period clam called Modiomorpha concentrica (Conrad, 1838).  It was found in Clark County, Indiana USA in the Jeffersonville Limestone. A coral is growing on part of the shell that is probably an Aulocystis. This fossil belongs to my cousin who has been cleaning it.

 

I used 1889 A Monograph of the Fossil Shells of the Silurian and Devonian Rocks of Kentucky by Henry Nettelroth (1835-1887) found here. This first image is from Plate II figure 10.

The last image is from Plate II, figure 11.

Rostroconch: Hippocardia

This is a rostroconch and is probably a Hippocardia cuneus (Conrad, 1840). It was found in the Louisville Limestone in Jefferson County, Kentucky. According to the Fossils of Ohio (1996) book, "Although the paleoenvironmental settings of some Silurian units in Ohio are such that rostroconchs could have been present, they have not been reported." (pages 132-133) So this fossil was found in the Silurian layer and is somewhat rare.

The rostroconch was at one time classified as a Pelecypoda but now have their own class as Rostroconchia. The section in the book only covered 4 pages so I am guessing these creatures are somewhat rare and not studied a great deal. The geologist that wrote the section was named Richard D. Hoare who was a professor at Bowling Green State University in Ohio from 1957-1990.

My cousin found this fossil and it appears he may have cleaned it with an air abrasive cleaner.