# Rockport Quarry Limestone

The Rockport Quarry Limestone is a geologic formation in Michigan. It preserves fossils dating back to the middle Devonian period.

## Fossil content

| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |

### Vertebrates

The Devonian vertebrate fauna of the Rockport Quarry Limestone is the most diverse in Michigan.

#### Acanthodians

Acanthodians reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| ?Machaeracanthus | ?M. sp. | | A single specimen (UMMP 13047). | | |

#### Cartilaginous fish

Cartilaginous fish reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| Phoebodus | P. cf. P. sophiae | Alpena, Michigan. | A tooth. | An early elasmobranch. | |
| ?Tamiobatis | ?T. sp. | "At the abandoned Kelly Island Limestone Quarry at Rockport State Park, Alpena County". | A single small spine (UMMP 13147). | A ctenacanthoid. | |

#### Placoderms

Placoderms reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes |
| Dinomylostoma | D. sp. | | | An arthrodire. |
| Dunkleosteus | D. sp. | Rockport Quarry, Alpena County. | A single incomplete right anterior ventrolateral (UMMP 16152). | An arthrodire. |
| Holonema | ?H. rugosum | | A single specimen (UMMP 3898). | An arthrodire. |
| Holonema | H. sp. | | 26 specimens. | An arthrodire. |
| Mylostoma | M. sp. | | A single specimen (UMMP 13612). | An arthrodire. |
| Placodermi | | At the abandoned Kelly Island Limestone Quarry at Rockport State Park, Alpena County. | 2 specimens (7M, VP. 522.) | Placoderms of unknown affinity. |
| Protitanichthys | P. rockportensis | | 59 specimens. | An arthrodire. |
| Ptyctodus | P. sp. | | A single specimen (UMMP 13045). | A ptyctodontid. |

### Invertebrates
#### Brachiopods

Brachiopods reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes |
| Chonetes | C. mediolatus | | | Also found in the Bell Shale, Ferron Point Formation and St. Laurent Limestone. |
| Pentamerella | P. sp. B | Basal 8 inches of the formation. | 2 specimens. | |
| Pholidostrophia | P. gracilis gracilis | | | Also found in the Bell, Ferron Point and Genshaw formations. |
| Schizophoria | S. ferronensis | Basal 8 inches of the formation. | | Also found in the Bell Shale, Ferron Point Formation and Silica Shale. |
| Schuchertella | S. crassa | | | Also found in the lower Bell Shale, Ferron Point Formation and Arkona Shale. |
| Spinulicosta | S. mutocosta | | | Also found in the Bell, Ferron Point, Four Mile Dam, Beebe School, Thunder Bay and Potter Farm formations. |
| Strophodonta | S. extenuata rockportensis | Lower 8 inches of the formation. | | |
| Tylothyris | T. rockportensis | | | Appears to be endemic to the Michigan Basin. |
| Tylothyris | T. subvaricosa | | | Also found in the Cedar Valley, Milwaukee, Mineola, Bell, Ferron Point, Genshaw, Alpena, Gravel Point, Norway Point and Potter Farm formations. |

#### Bryozoans

Bryozoans reported from the Rockport Quarry Limestone :
| Genus | Species |
| Fenestellidae | Species A |
| Fenestellidae | Species B |
| Fenestellidae | Species C |
| Trepostomata | Species A |
| Trepostomata | Species B |

#### Crustaceans

Crustaceans reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| Ostracoda | | | | | |
| Phlyctiscapha | P. rockportensis | Basal part of the formation. | | An ostracod. | |

#### Echinoderms

Echinoderms reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| Crinoidea | | | "Observed as disaggregated ossicles, ossicles stacked en echellon, and fragments of columnals". | | |

#### Molluscs

Molluscs reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| Cephalopoda | | | "All specimens collected as single-hand specimens". | | |
| Gastropoda | | | | | |

#### Sponges

Sponges reported from the Rockport Quarry Limestone :
* Genus
* Clathrodictyidae
* Idiostromatidae
* Stromatoporidae

#### Trilobitomorphs

Trilobitomorphs reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| Trilobitomorpha | | 200 m south of the large sinkhole on the west wall of Rockport Quarry. | | | |

### Plants and algae

Plants and algae reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material |
| Calcisphera | C. sp. A | "Abandoned quarry of the Onaway Limestone Company on the shore of Black Lake". | |
| Calcisphera | C. sp. B | "Abandoned quarry of the Onaway Limestone Company on the shore of Black Lake". | |
| Rhodophyta | Indeterminate | 200 m south of the large sinkhole on the west wall of Rockport Quarry. | |
| Vermiporella | | | "Observed as transverse sections, most specimens now irregular in shape due to crushing". |

### Cyanophytes

Cyanophytes reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes |
| Genus and species indeterminate | Indeterminate | | "Spherical bodies 3-5 microns in diameter". | |
| Oncolite | | | | "Some post-depositional crushing of the sample has occurred". |
| Renalcis | | "Abandoned quarry of the Onaway Limestone Company on the shore of Black Lake". | | |

### Foraminifera

Foraminifera reported from the Rockport Quarry Limestone :
| Genus | Species | Presence | Material | Notes | Images |
| Family indet. | | | "Found sparsely as solitary individuals in 6 specimens". | | |
| Nodosinellidae | | | | | |