Unusual Edrioasteroid Assemblage from Canada

Description: This superb Echinoderm assemblage shows numerous members of the Edrioasteroidea, or edrioasteroids. This group of starfish relatives derives their name from the Greek for seated star, and exemplifies their sessile nature. Unlike the highly mobile starfish, Edrioasteroids were attached to a substrate by a short thick stalk covered with plates. The ambulacra (radiating feeding grooves) were covered by large rooflike plates which were capable of being raised, and were arrayed in a characteristic spiral pattern. These echinoderms arose during the Lower Cambrian, and survived until the Middle Pennsylvanian. This assemblage is believed to be the result of rapid burial, preserving so may in a fine state. The Cryptogoleus are the larger examples.