Saturday, April 23, 2022

Caritodens demissa Pelecypod Fossil


The Caritodens demissa (Conrad, 1842) pelecypod fossil found in Jefferson County, Indiana USA (near Madison). Fossil dates to the Ordovician Period. The book Index Fossils of North America by Hervey W. Shimer and Robert R. Shrock 1944 lists this fossil as Pterinea demissa (Conrad, 1842) of the Upper Ordovician Period (Maysville-Richmond). It is described as "Distinguished by its strong concentric growth lines and large anterior ear." The genus Pterina was named by Georg August Goldfuss (1782-1848) in 1832. Original species named Avicula demissa in 1842 by Timothy Abbott Conrad (1803-1877) in the Journal of Academy of Natural Sciences in Philadelphia Volume VIII page 242, plate XIII, figure 3.

Thanks to Kenny for the image.

Saturday, April 16, 2022

Elaeacrinus verneuili Blastoid Fossil

These pictures show what appears to be an Elaeacrinus verneuili (Römer [aka Roemer], 1851) blastoid fossil. This specimen is partially embedded in matrix and measures about 15 mm long. I use to think Devonian blastoids like this were rare but after exploring a site after an hour or so one usually is found.

It was found in the Jeffersonville Limestone of Clark County, Indiana USA. It dates to the Devonian Period.

This species is also attributed to Gerard Troost (1776-1850) who identified it as Pentremites verneuili in 1841 in the 6th Report Geological State Tennessee on page 14. He later published two more mentions in 1849 and 1850 as Olivanites verneuili and Olivanites verneuili.[Source]