Monday, May 10, 2010

Silurian Crinoid Arm

Unidentified arm off a crinoid calyx found in Clark County, Indiana in the Waldron Shale.  The fossil is from the Silurian Period (443 to 416 million years ago).  High hopes that sand blasting will reveal more details of this fossil including the pinnules or feather looking part of the arm.

2 comments:

soliussymbiosus said...

At first, I thought that it was a cirri, but when I "opened" the photo, I noticed the pinnate structure. It will be interesting to see how it preps out.

Fossil Detective said...

I am wondering if it belongs to an Eucalyptocrinites crinoid since that is what the Waldron Shale is known for.

Hoping the matrix is pretty soft for the sand abrasion to quickly reveal more details.