# Castle Hayne Limestone

The Castle Hayne Limestone (also called the Castle Hayne Formation) is a middle Eocene-aged geologic formation in North Carolina, USA. It consists of cobble to pebble sized clasts, usually rounded, coated with phosphate and glauconite in a limestone matrix. The formation has been dated to the middle Eocene, but its exact age remains uncertain; however, it is generally thought to date to the Lutetian or early Bartonian.

## Description

The Castle Hayne Formation is divided into three submembers: the New Hanover member, the Comfort Member, and the Spring Garden Member. The New Hanover member is the oldest member and is characterizes by cobbles and pebbles, fine sand, glauconite, and phosphate in a fine limestone matrix. The most common fossils are shark and ray teeth. Index fossils place this member in the middle Eocene. The Comfort member lies above the New Hanover member. It contains bryozoa and sea urchin fossils and beds of glauconite and phosphate pebbles that mark breaks in deposition. The Comfort member was deposited in the late middle Eocene and is overlain by the Spring Garden member. The Spring Garden member is a siliceous rock cemented with calcite and containing detrital phosphate. Mollusc bivalves account for up to 75% of the composition in some areas and molds of molluscs shells filled with silica are common. Index fossils indicate this member was also deposited in the late middle Eocene.

## Vertebrate paleobiota

Based on the Paleobiology Database:

### Cartilaginous fish
#### Sharks

Sharks of the Castle Hayne Limestone :
| Genus | Species | Notes |
| Anomotodon | A. novus | A goblin shark. |
| Brachycarcharias | B. koerti | A sand shark. |
| Macrorhizodus | M. americanus (=Isurus americanus) | A lamnid mackerel shark. |
| Odontaspis | O. sp. | A sand shark. |
| Otodus | O. angustidens | A megatooth shark. |
| Striatolamia | S. macrota | A sand shark. |

#### Rays

Rays of the Castle Hayne Limestone :
| Genus | Species | Notes |
| Dasyatidae indet. | | A whiptail stingray of uncertain affinities. |
| Myliobatis | M. sp. | An eagle ray. |
| Pristis | P. curvidens | A sawfish. |
| Rhinoptera | R. sp. | A cownose ray. |

### Ray-finned fish

Ray-finned fish of the Castle Hayne Limestone :
| Genus | Species | Material | Notes |
| Carangidae indet. | | | A jackfish. |
| Cylindracanthus | C. sp. | Rostra | A fish of uncertain affinities. |
| Xiphiorhynchus | X. antiquus | | A xiphiid billfish, related to modern swordfish. |

### Mammals
#### Cetaceans

Cetaceans of the Castle Hayne Limestone :
| Genus | Species | Member | Material | Notes |
| Crenatocetus | C. rayi | Comfort | | A protocetid. Type locality for this genus. |
| Cynthiacetus | C. maxwelli | | | A basilosaurid. |
| Pachycetus | P. wardii | | | A basilosaurid. |
| ?Remingtonocetidae indet. | | | A tooth. | A potential remingtonocetid. Possibly the first record of this family from North America, and provides evidence that this family had a trans-Atlantic distribution. |

#### Sirenians

Sirenians of the Castle Hayne Limestone :
| Genus | Species | Member | Notes | Images |
| Protosiren | P. sp | | A protosirenid sirenian. | |

## Invertebrate paleobiota
### Molluscs

| Genera | Species | Notes |
| Chione | C. sp | |
| Crassatella | C. wilcoxi C. sp | A crassatellid bivalve. |
| Ensis | E. sp | |
| Flemingostrea | F. sp | |
| Giganostrea | G. trigonalis | An extinct group of oyster. |
| Glyptoactis | G. sp | |
| Panopea | P. sp | A close relative of the modern geoduck. |
| Pecten | P. membranosus | An extinct bivalve that belonged to the same genus as most modern scallops. |
| Pholadomya | P. sp | |
| Plicatula | P. filamentosa | |
| Venericardia | V. sp | |

### Cephalopods

| Genera | Species | Notes | Images |
| Anomalosaepia | A. vernei A. mariettani A. alleni A. andreane A. sp | An extinct group of cuttlefish that was also found in Egypt and belonged to the family Anomalosaepiidae. | |
| Aturia | A. alabamensis | Belongs in its own family: the Aturiidae. | |
| Beloptera | B. sp | Another extinct group of cuttlefish that was found in several localities in Europe. | |
| Conchorhynchus | C. furrus | Has not been classified into any specific cephalopod group yet. | |
| Eutrephoceras | E. carolinensis | First originated during the Cretaceous period. | E. dorbignyanum, a related species. |
| Rhyncolites | R. sp R. minimus R. aturensis | An extinct group of nautiloid that has not yet been classified into any specific family. | |