Wednesday, July 3, 2013

Pyritized Crinoid Calyx Cup

This fossil appears to be the bottom of a Lyriocrinus calyx cup found in the Waldron Shale of Clark County, Indiana. It is dated to the Middle Silurian Period (425-419 million years ago).  The reason I identified it as Lyriocrinus as I found another cup nearby. The most common crinoid cup found is the Eucalyptocrinus which is this layer's index fossil. Fossil is about 3 cm wide.


Thursday, June 6, 2013

Waldron Shale Ostracod Fossil

Here is a picture of an ostracode microfossil found in the Waldron Shale of Clark County, Indiana, USA. It is about 420 million years old which puts it in the Silurian Period.

After looking at the paper entitled "A Study of the Ostracoda Fauna of the Waldron Shale, Flat Rock Creek, St. Paul, Indiana" by Horace Noble Coryell and Marjorie Williamson published by the The American Museum of Natural History (New York City, Number 870) on July 6, 1936, it appears to be some sort of Cornulina sp.  See their paper here: WEB LINK.

Thanks to Kenny for the picture.

Monday, May 27, 2013

Waldron Shale Scolecodont Fragment

This picture is of a microfossil called a scolecondont (part of a worm jaw). It was found in the Waldron Shale of Clark County, Indiana, USA. The age is around 420 million years old which would place it in the Silurian Period.

It reminds me of a Silurian scolecodont found in Sweden called Kettnerites sp.  Also one found in New York called Nereidavus invisibilis. I have not been able to find much research on the ones found in the American Waldron Shale though.

Thanks to Kenny for the picture.