Rugose corals in Paleozoic limestone. (public display, Idaho Museum of Natural History, Pocatello, Idaho, USA)

The limestone shown above is dominated by solitary rugose corals. Rugose corals are an extinct group of solitary and colonial cnidarians. They are often nicknamed "horn corals", in reference to the upside-down horn shape of the skeletons of solitary forms (Ex: <a href="https://www.flickr.com/photos/jsjgeology/15590522272">www.flickr.com/photos/jsjgeology/15590522272</a>). Solitary rugose corals made solid, tapering skeletons of calcite (CaCO3 - calcium carbonate). During life, a polyp (sea anemone animal) lived in a cup-like depression at the top of the skeleton.

These rugose corals appear silicified (the original calcite skeletons have been replaced by quartz/silica, SiO2).

Classification: Animalia, Cnidaria, Anthozoa, Rugosa

Stratigraphy: unrecorded/undisclosed

Locality: unrecorded/undisclosed

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