Saturday, January 19, 2013

Unprepped Silurian Crinoid Holdfast

This crinoid holdfast is maybe the most extensive one I have every found. It is still quite embedded in Waldron Shale matrix but the large number of roots are exposed. Somewhat amazing how much this animal has such similar characteristics to that of a plant. While not able to make an exact identification it appears to be the holdfast of an Eucalyptocrinus of the Silurian Period. Fossil found in Clark County, Indiana, USA.

On the other side of the matrix piece, this smaller holdfast was found that appears to be like a large tap root with small branches coming off it.
Identification is based off of images of Eucalyptocrinus roots (holdfasts) from illustrations from Plate 19 (Figures 6-7) Indiana Department of Geology and Natural History Eleventh Annual Report John Collett State Geologist 1881.

Also plate 20 shown below.