Calcareous Algae and Stromatolites

Receptaculites

Receptaculites is the name-bearing genus for an extinct group of conspicuous benthic marine genera, the receptaculitids (formally Receptaculitaceae or Receptaculitidae)…

Cyclocrinitids

Early (mid-Ordovician--early-Silurian) Dasycladalean algae, resembling but probably not closely related to the Receptaculitids.

Beresellaceae

Beresellaceae is an extinct family of organisms of uncertain affinity, sometimes placed within the Metazoa (multicellular animals), but tentatively assigned to the green…

Algospongia

Algospongia is a class of small, calcified fossil organisms of uncertain taxonomic position, assigned in a comprehensive 2010 review to "Animalia" incertae sedis (possibly…