Echinosphaerites
Echinosphaerites, genus of cystoids, an extinct group related to the sea lily and starfish, found as fossils in Ordovician marine rocks (between 505 and 438 million years old). It is a useful guide, or index, fossil for Ordovician rocks and time.
Citation Information
Article Title:
Echinosphaerites
Website Name:
Encyclopaedia Britannica
Publisher:
Encyclopaedia Britannica, Inc.
Date Published:
27 January 2015
Access Date:
February 22, 2025