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.
Material from the Castle Hayne formation has been brought to the surface in the lower Cape Fear River estuary through channel maintenance dredging conducted by the United States Army Corps of Engineers beginning in the late 19th century. Dredge spoil deposits along the river margins contain reworked Castle Hayne limestone intermixed with younger Miocene and Pliocene marine sediments, forming a chain of artificial islands near Wilmington, North Carolina. Fossilized shark teeth and ray dental plates from these deposits are accessible along the shoreline of the spoil islands during low tide.
Vertebrate paleobiota Based on the Paleobiology Database:
Cartilaginous fish
Sharks Sharks of the Castle Hayne LimestoneGenusSpeciesMemberMaterialNotesImagesAnomotodonA. novusA goblin shark.BrachycarchariasB. koertiA sand shark.Macrorhizodus M. americanus (=Isurus americanus)A lamnid mackerel shark.OdontaspisO. sp.A sand shark.OtodusO. angustidensA megatooth shark.StriatolamiaS. macrotaA sand shark.
Rays Rays of the Castle Hayne LimestoneGenusSpeciesMemberMaterialNotesImagesDasyatidae indet.A whiptail stingray of uncertain affinities.MyliobatisM. sp.An eagle ray.PristisP. curvidensA sawfish.RhinopteraR. sp.A cownose ray.
Ray-finned fish Ray-finned fish of the Castle Hayne LimestoneGenusSpeciesMemberMaterialNotesImagesCarangidae indet.A jackfish.CylindracanthusC. sp.RostraA fish of uncertain affinities.XiphiorhynchusX. antiquusA xiphiid billfish, related to modern swordfish.
Mammals
Cetaceans Cetaceans of the Castle Hayne LimestoneGenusSpeciesMemberMaterialNotesImagesCrenatocetusC. rayiComfortA protocetid. Type locality for this genus.CynthiacetusC. maxwelliA basilosaurid.PachycetusP. wardiiA 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 LimestoneGenusSpeciesMemberNotesImagesProtosirenP. spA protosirenid sirenian.
Invertebrate paleobiota
Molluscs
GeneraSpeciesNotesImagesChione C. spCrassatella C. wilcoxi C. spA crassatellid bivalve.EnsisE. spFlemingostreaF. spGiganostreaG. trigonalisAn extinct group of oyster.Glyptoactis G. spPanopeaP. spA close relative of the modern geoduck.PectenP. membranosusAn extinct bivalve that belonged to the same genus as most modern scallops.PholadomyaP. spPlicatulaP. filamentosaVenericardiaV. sp
Cephalopods GeneraSpeciesNotesImagesAnomalosaepiaA. vernei
A. mariettani
A. alleni
A. andreane
A. spAn extinct group of cuttlefish that was also found in Egypt and belonged to the family Anomalosaepiidae.AturiaA. alabamensisBelongs in its own family: the Aturiidae.BelopteraB. spAnother extinct group of cuttlefish that was found in several localities in Europe.ConchorhynchusC. furrusHas not been classified into any specific cephalopod group yet.EutrephocerasE. carolinensisFirst originated during the Cretaceous period.E. dorbignyanum, a related species.RhyncolitesR. sp R. minimus
R. aturensisAn extinct group of nautiloid that has not yet been classified into any specific family.
See also
List of fossiliferous stratigraphic units in North Carolina
References