Ordovician Clam: Caritodens demissa

The following pictures show an Ordovician period clam called Caritodens demissa (Conrad, 1842). This clam was found in eastern Jefferson County, Kentucky (just outside of Louisville, Kentucky). It was found in the Grant Lake Formation. Part of clam is still embedded in the rock matrix. The fossil is about 4 cm wide and 3.5 cm long. The Fossils of Ohio book says on page 139 this clam is common. It describes it as "a large species distinguished by auricles (large winglike extensions of the hinge), strongly developed comarginal ridges, and the lack of any radial ornamentation." A picture can be found in the book at Figure 12-1.1. Here is a link to another fossil found on the KYANA Geological Society website. This might be one at this link at the Kentucky Paleontological Society website. This link on the Dry Dredgers website shows a number of Caritoden pelecypods they have found. Learn more about this pelecypod fossil at one of my other postings.

A Pseudofossil Called Dendrites

If you type pseudofossil into the image search engine section of Google, images like the ones shown below will start to appear. These mineral deposits of manganese oxide were created when mineral enriched water seeped into the cracks of this rock. After the water departed, these mineral patterns were left.

The patterns remind me of a little branching plant or fractals defined by mathematics.

This rock is probably Devonian so these pattern formed sometime in the last 400 million years.

Silurian Dawsonoceras Cephalopod Imprint

This was found somewhere in Louisville, Kentucky. I found the images on my computer but I did not note where it was found. It is Silurian period and probably Louisville Limestone. It is the imprint of a Dawsonoceras cephalopod shell. These are great finds when they still have parts of the shell texture. The growth lines are sinusoidal in nature and quite a work of art. One section of the fossil has some pyrite crystals.