Late Ordovician

Ashgill Series

Llangynog, Berewyn Hills, North Wales, England

21mm crown.

Cystoid.

Heliocrinites is a genus of primitive stalked echinoderm said to belong to the Class Rhombifera.  It is known from the Ordovician of Europe, North Africa, and the Middle East.  It has been identified as a cystoid or a relative of them.

Cystoids belong to an extinct order of echinoderms from the Ordovician to Devonian Periods.  Similar to crinoids, they had somewhat rounded, plated, bodies attached to a stalk that was anchored to the sea bottom.