This post shows a series a pictures of a small pea sized (3-6 mm) fossil found in the Silurian Period Waldron Shale of southern Indiana. Is this some sort of small calyx, blastoid, or something else?
The top has a small 5 petal flower like pattern that reminds me of crinoid calyx. It sort of reminds me of a Pisocrinus crinoid but the base is circle enclosed in a triangle shape on these fossils. The tops on some of the fossils have points the bend inward which seems more like a blastoid.
If anyone has some identification ideas on these fossils, let me know. Thanks!
UPDATE (1/7/2011): After reading some great comments about these specimens, I e-mailed Dr. Colin Sumrall at the University of Tennessee in Knoxville for advice. He identified it as a member of the Coronoidea and it is called Stephanocrinus gemmiformis. It is somewhat of a confusing crinoid and he pointed out it is "basically a blastoid with erect arms".
Kenny has found some of these fossils as well and sent me some images he took with a microscope. One can see a line like pattern on parts of the fossil plus a magnified view of the triangle shape on the fossil bottom.