An extinct group that has been attributed to the hydrozoans, sponges, foraminifera, bryozoans, algae, or regarded as a phylum with no modern representatives. Stromatoporoids are calcareous masses built up of horizontal laminae and vertical pillars. The upper surfaces show a pattern of polygonal markings and may have swellings and stellate grooves. They are found in limestones of Cambrian to Cretaceous age, often forming reefs in Ordovician to Devonian times.
Subjects: Earth Sciences and Geography — Zoology and Animal Sciences.