(from the article `bioherm`) ...corals, echinoderms, gastropods, mollusks, and others; fossil calcareous algae are prominent in some bioherms. A structure built by similar ...
biostrome An accumulation of fossils that are distinctly bedded but do not form a mound-like or reef-like structure (bioherm); a fossil bed having no pronounced topographical relief.
Laterally extensive reefs made up of shells