The Flickr Rugosans Image Generatr

Siphonophrentis gigantea (Lesueur 1821) - fossil rugose coral from the Devonian of Ohio, USA.

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: www.flickr.com/photos/jsjgeology/15590522272). Rugose corals made a solid skeleton of calcite (CaCO3 - calcium carbonate). Here here is a large solitary rugose coral, appropriately named Siphonophrentis gigantea. During life, a polyp (sea anemone animal) lived in a cup-like depression at the top of the skeleton.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Amplexidae

Stratigraphy: Columbus Limestone, Middle Devonian

Locality: unrecorded / undisclosed site in the Marblehead Peninsula (possibly from a quarry), far-northern Ohio, USA
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See info. at:
en.wikipedia.org/wiki/Rugosa

Kueichouphyllum sinense Yu, 1931 - fossil rugose coral from the Mississippian of China.

This is a solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.
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Exhibit info.:

This unusual, large, twisted horn coral species is apparently common in some formations in the mountainous Guizhou Province of southwest China.
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Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Aulophyllidae

Stratigraphy: Shangsi Formation, Visean Stage, Middle Mississippian

Locality: unrecorded / undisclosed site in Guizhou Province, South China

Kueichouphyllum sinense Yu, 1931 - fossil rugose coral from the Mississippian of China.

This is a solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.
------------------------------------
Exhibit info.:

This unusual, large, twisted horn coral species is apparently common in some formations in the mountainous Guizhou Province of southwest China.
------------------------------------
Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Aulophyllidae

Stratigraphy: Shangsi Formation, Visean Stage, Middle Mississippian

Locality: unrecorded / undisclosed site in Guizhou Province, South China

Heterophrentis sp. - pyritized fossil rugose coral from the Devonian of Ohio, USA.

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

The coral's skeleton is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace hard parts or it can be a coarsely-crystalline coating atop calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Streptelasmatidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Heterophrentis sp. - pyritized fossil rugose coral from the Devonian of Ohio, USA.

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

The coral's skeleton is now composed of pyrite ("fool's gold" - FeS2, iron sulfide), a preservation style referred to as replacement. The specimen comes from the Middle Devonian Silica Formation (also known as the Silica Shale) in northwestern Ohio. Pyritized fossils are relatively common in the unit - pyrite can replace hard parts or it can be a coarsely-crystalline coating atop calcareous shells.

The most common fossil replacement minerals are quartz, pyrite, and apatite. Quartz is SiO2 (silica) - fossils that have been quartz-replaced are said to be silicified (silicification). Many silicified fossils have rounded to pustulose structures covering their surfaces. These are called beekite rings, but they're composed of ordinary quartz. Replacement by apatite (calcium phosphate) is called phosphatization.

Other minerals have also been found replacing minerals - many are quite rare. Reported fossil replacement minerals include: anglesite, apatite, barite, calamine, calcite, cassiterite, celestite, cerargyrite, cerussite, chalcocite, cinnabar, copper, dolomite, fluorite, galena, garnet, glauconite, gumbelite, gypsum, hematite, kaolinite, limonite, magnesite, malachite, marcasite, margarite, opal, pyrite, romanechite/psilomelane, siderite, quartz, silver, smithsonite, specular hematite, sphalerite, sulfur, uranium minerals, and vivianite.
(List mostly from info. in Hartzell, 1906 and Klein & Hurlbut, 1985)

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Streptelasmatidae

Stratigraphy: Silica Formation, Givetian Stage, upper Middle Devonian

Locality: unrecorded / undisclosed quarry in the Sylvania area, far-northern Lucas County, northwestern Ohio, USA

Tabulophyllum sp. - fossil rugose coral from the Mississippian of Utah, USA.

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Kyphophyllidae

Stratigraphy: Chainman Formation, Mississippian

Locality: unrecorded / undisclosed site in Millard County, western Utah, USA

Tabulophyllum sp. - fossil rugose coral from the Mississippian of Utah, USA.

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Stauriida, Kyphophyllidae

Stratigraphy: Chainman Formation, Mississippian

Locality: unrecorded / undisclosed site in Millard County, western Utah, USA

Acrocyathus proliferus (Hall, 1858) - fossil colonial coral from the Mississippian of Alabama, USA.

Rugose corals, or "horn corals", are an extinct group - they only occur in Paleozoic rocks. Some rugosans were colonial, but most were solitary, with a calcitic skeleton that tapered to a point. The pointed end was in the seafloor sediments. A sea anemone-type organism (polyp) originally occupied the cup's living space at top. Coral polyps have numerous tentacles with stinging cells (nematocysts) that paralyze prey.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Acrocyathidae

Stratigraphy: Bangor Limestone, Chesterian Series, Upper Mississippian

Locality: unrecorded / undisclosed site at or near the town of Huntsville, northern Alabama, USA
----------------------------------
See info. at:
en.wikipedia.org/wiki/Rugosa

Acrocyathus proliferus (Hall, 1858) - fossil colonial coral from the Mississippian of Alabama, USA.

Rugose corals, or "horn corals", are an extinct group - they only occur in Paleozoic rocks. Some rugosans were colonial, but most were solitary, with a calcitic skeleton that tapered to a point. The pointed end was in the seafloor sediments. A sea anemone-type organism (polyp) originally occupied the cup's living space at top. Coral polyps have numerous tentacles with stinging cells (nematocysts) that paralyze prey.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Acrocyathidae

Stratigraphy: Bangor Limestone, Chesterian Series, Upper Mississippian

Locality: unrecorded / undisclosed site at or near the town of Huntsville, northern Alabama, USA
----------------------------------
See info. at:
en.wikipedia.org/wiki/Rugosa

Acrocyathus proliferus (Hall, 1858) - fossil colonial coral from the Mississippian of Alabama, USA.

Rugose corals, or "horn corals", are an extinct group - they only occur in Paleozoic rocks. Some rugosans were colonial, but most were solitary, with a calcitic skeleton that tapered to a point. The pointed end was in the seafloor sediments. A sea anemone-type organism (polyp) originally occupied the cup's living space at top. Coral polyps have numerous tentacles with stinging cells (nematocysts) that paralyze prey.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Acrocyathidae

Stratigraphy: Bangor Limestone, Chesterian Series, Upper Mississippian

Locality: unrecorded / undisclosed site at or near the town of Huntsville, northern Alabama, USA
----------------------------------
See info. at:
en.wikipedia.org/wiki/Rugosa

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa

Stratigraphy: unknown (but probably from the Columbus Limestone, Middle Devonian)

Locality: loose piece in driveway gravel in Ohio (likely sourced from an Ohio quarry)

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa

Stratigraphy: unknown (but probably from the Columbus Limestone, Middle Devonian)

Locality: loose piece in driveway gravel in Ohio (likely sourced from an Ohio quarry)

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa

Stratigraphy: unknown (but probably from the Columbus Limestone, Middle Devonian)

Locality: loose piece in driveway gravel in Ohio (likely sourced from an Ohio quarry)

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa

Stratigraphy: unknown (but probably from the Columbus Limestone, Middle Devonian)

Locality: loose piece in driveway gravel in Ohio (likely sourced from an Ohio quarry)

This is a fossil solitary rugose coral, commonly known as a "horn coral". Rugosans are an extinct group - they only occur in Paleozoic rocks. The soft parts were sea anemone-like creatures called polyps. The polyps made calcareous hard-part skeletons. Most rugosans were solitary, but some were colonial.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa

Stratigraphy: unknown (but probably from the Columbus Limestone, Middle Devonian)

Locality: loose piece in driveway gravel in Ohio (likely sourced from an Ohio quarry)

This is a fossil rugose coral ("horn coral"), an extinct group that included solitary and colonial forms. The original skeleton was calcareous but this one has been silicified - the calcite was replaced by quartz (SiO2).

This is a fossil rugose coral ("horn coral"), an extinct group that included solitary and colonial forms. The original skeleton was calcareous but this one has been silicified - the calcite was replaced by quartz (SiO2).

Grewingkia canadensis (Billings, 1862) - horn corals in fossiliferous limestone from the Ordovician of Ohio, USA. (CMC IP 81956, Cincinnati Museum of Natural History & Science, Cincinnati Museum Center, Cincinnati, Ohio, USA)

The famous Cincinnatian Series of the tristate area of Ohio-Kentucky-Indiana has some of the richest fossiliferous rocks on Earth. Cincinnatian rocks were deposited in relatively shallow marine facies during the Late Ordovician. The Cincinnatian succession is mostly interbedded limestones and shales. Most of the limestones are event beds (= tempestites), deposited during ancient storms.

The fossils seen here are solitary rugose corals, 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: www.flickr.com/photos/jsjgeology/15590522272). 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.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Streptelasmatidae

Stratigraphy: unrecorded unit in the Richmondian Stage, upper Cincinnatian Series, upper Upper Ordovician

Locality: unrecorded / undisclosed site at or near the town of Cincinnati, southwestern Ohio, USA
----------------------------------
Info. at:
en.wikipedia.org/wiki/Rugosa

Grewingkia canadensis (Billings, 1862) - horn corals in fossiliferous limestone from the Ordovician of Ohio, USA. (CMC IP 81956, Cincinnati Museum of Natural History & Science, Cincinnati Museum Center, Cincinnati, Ohio, USA)

The famous Cincinnatian Series of the tristate area of Ohio-Kentucky-Indiana has some of the richest fossiliferous rocks on Earth. Cincinnatian rocks were deposited in relatively shallow marine facies during the Late Ordovician. The Cincinnatian succession is mostly interbedded limestones and shales. Most of the limestones are event beds (= tempestites), deposited during ancient storms.

The fossils seen here are solitary rugose corals, 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: www.flickr.com/photos/jsjgeology/15590522272). 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.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Streptelasmatidae

Stratigraphy: unrecorded unit in the Richmondian Stage, upper Cincinnatian Series, upper Upper Ordovician

Locality: unrecorded / undisclosed site at or near the town of Cincinnati, southwestern Ohio, USA
----------------------------------
Info. at:
en.wikipedia.org/wiki/Rugosa

Grewingkia canadensis (Billings, 1862) - horn corals in fossiliferous limestone from the Ordovician of Ohio, USA. (CMC IP 81956, Cincinnati Museum of Natural History & Science, Cincinnati Museum Center, Cincinnati, Ohio, USA)

The famous Cincinnatian Series of the tristate area of Ohio-Kentucky-Indiana has some of the richest fossiliferous rocks on Earth. Cincinnatian rocks were deposited in relatively shallow marine facies during the Late Ordovician. The Cincinnatian succession is mostly interbedded limestones and shales. Most of the limestones are event beds (= tempestites), deposited during ancient storms.

The fossils seen here are solitary rugose corals, 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: www.flickr.com/photos/jsjgeology/15590522272). 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.

Classification: Animalia, Cnidaria, Anthozoa, Rugosa, Streptelasmatidae

Stratigraphy: unrecorded unit in the Richmondian Stage, upper Cincinnatian Series, upper Upper Ordovician

Locality: unrecorded / undisclosed site at or near the town of Cincinnati, southwestern Ohio, USA
----------------------------------
Info. at:
en.wikipedia.org/wiki/Rugosa