Blastoidia

Blastoids are fairly common for an Echidermata.
Blastoids are a sea plant that grew in Kentuky. The fossil grew on a stem and has five holes on the top in the formation of a star. There is also what looks like a small starfish wraped around the outside of the fossil. They are some times perfectly round. The more common blastoids are pentamites and cryptoblastos. They belong to the crustacions. The common size of these rocks is 2'' to 0.5"

NOTE- -wonderful additions to any collection.