# Columbus Limestone

The Columbus Limestone is a mapped bedrock unit consisting primarily of fossiliferous limestone. It occurs in Ohio, Pennsylvania, and Virginia in the United States, and in Ontario, Canada.

## Description
### Depositional environment

The depositional environment was most likely shallow marine.

### Stratigraphy

The Columbus conformably overlies the Lucas Dolomite in northeastern Ohio, and unconformably overlies other dolomite elsewhere. It unconformably underlies the Ohio Shale in northwestern Ohio and the Delaware Limestone in eastern Ohio.
Its members include: Bellepoint, Marblehead, Tioga Ash Bed, Venice, Delhi, Klondike, and East Liberty.

### Notable Exposures

* The type section is located in Columbus, Ohio.
* The glacial grooves on Kelleys Island are cut into the Columbus Limestone. It is also quarried there.
* An exposure in Ontario is located at Ingersoll, Ontario.

## Fossils

The Columbus Limestone contains brachiopods, trilobites, bryozoans, mollusks, corals, stromatoporoids and echinoderms (including crinoids).
Due to their mid-continent depositional environment, the fossils are almost free of deformation caused by tectonic activity common in the Appalachian Mountains.

### Corals

Tabulata :
| Taxon | Species |
| Syringopora | S. tabulata |
| Favosites | F. hemispherica minuta |
| Emmonsia | E. polymorpha |
| Thamnoptychia | T. alternans |
| Pleurodictyum | Indeterminate |
| Coenites | C. dublinensis |
Rugosa :
| Taxon | Species |
| Prismatophyllum | P. rugosum |
| Hexagonaria | H. anna |
| Eridophyllum | E. seriale |
| Synaptophyllum | S. simcoense |
| Amplexus | A. yandelli |
| Zaphrenthis | Z. perovalis |
| Heterophrentis | H. nitida |
| Cystiphylloides | C. americanum |
| Odontophyllum | O. convergens |
| Siphonophrentis | S. gigantea |
| Hadrophyllum | H. dorbignyi |

### Cephalopods

| Taxon | Species | Notes |
| Werneroceras | W. staufferi | Goniatite |
| Tornoceras | T. eberlei | Goniatite |
| Goldringia | G. cyclops | |

### Other Invertebrates

| Taxon | Species | Notes |
| Spirifer | S. macrothyris | Brachiopod |
| Brevispirifer | B. gregarius | Brachiopod |
| Laevidentalhum | L. martinei | Gastropod |
| Nucleocrinus | N. verneulli | Crinoid |

### Fish

| Taxon | Species | Notes |
| Drepanaspidae | Indeterminate | From the East Liberty Member ("East Liberty bone bed") |
| Cephalaspidae | | From the East Liberty Member ("East Liberty bone bed") |
| Gyracanthus? | | From the East Liberty Member ("East Liberty bone bed") |
| Plectrodus | | From the East Liberty Member ("East Liberty bone bed") |
| Acanthodii | | From the East Liberty Member ("East Liberty bone bed") |
| Machaeracanthus | M. major | From the East Liberty Member ("East Liberty bone bed") |
| "Acanthoides" | A. dublinensis | From the East Liberty Member ("East Liberty bone bed") |
| Coccosteus | C. spatulatus | From the East Liberty Member ("East Liberty bone bed") |
| Ptyctodus | | From the East Liberty Member ("East Liberty bone bed") |
| Rhynchodus | | From the East Liberty Member ("East Liberty bone bed") |
| Palaeomylus | | From the East Liberty Member ("East Liberty bone bed") |
| Cladoselachidae | | From the East Liberty Member ("East Liberty bone bed") |
| Phoebodus | | From the East Liberty Member ("East Liberty bone bed") |
| Onychodus | O. sigmoides | From the East Liberty Member ("East Liberty bone bed") |

## Age

Relative age dating of the Columbus Limestone places it in the Early to Middle Devonian period.

## Economic Uses

The Columbus has been mined for aggregate. Its Calcium carbonate content is 90% or higher.