Tholocrinus spinosus Calyx Crinoid Fossil

These pictures are of a recent fossil find from the Glen Dean Member of Grayson County, Kentucky USA. It is a crinoid calyx fossil that appears to be a Tholocrinus spinosus (Wood, 1909). The fossil dates to the Mississippian Period.  Thanks to Kenny for the images.

 

In 1909, Elvira Wood (1865-1928) published A Critical Summary of Troost's Unpublished Manuscript on the Crinoids of Tennessee. On page 93, she names a new crinoid species Hydreionocrinus spinosus after the fossil by Wetherby who described it in 1881 as Hydreionocrinus depressus found by Troost. She writes that Wetherby had actually found a new species and thus she names it. It's genus was later changed to Tholocrinus (Kirk, 1939).

Pterotocrinus acutus Crinoid Calyx With Snail

 

This picture is a recent fossil find from the Glen Dean Member of Grayson County, Kentucky USA. It is a crinoid calyx fossil that appears to be a Pterotocrinus acutus (Wetherby, 1879). The fossil dates to the Mississippian Period. 

The most interesting part of the fossil is when it photographed from the top revealing a gastropod was attached to its anal tube when they both died. A somewhat common relationship found in the fossil record between these two creatures.

Thanks to Kenny for the image.

Platyceras Snail Fossil

 

Here is a recent find from Grayson County, Kentucky USA. It is a gastropod fossil that appears to be Platyceras sp. (Conrad, 1840), genus is also known as Orthonychia (Hall, 1843). Fossil dates to the Mississippian Period of the Glen Dean Member.

Thanks to Kenny for the image.