# Marshalltown Formation

The Marshalltown Formation is a Late Cretaceous (Campanian)-aged geologic formation in New Jersey and Delaware, US. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation. It contains the most extensive Campanian-aged dinosaur fauna from New Jersey and Delaware.
The famous Ellisdale Fossil Site, a konzentrat-lagerstätten which contains one of the most diverse Cretaceous vertebrate assemblages (likely rapidly buried in a massive flood event) known from eastern North America/former Appalachia, is an exposure of this formation.
The Marshalltown Formation stretches across southern New Jersey to northern Delaware, and is largely composed of marine sediments deposited off the eastern shore of Appalachia, although the Ellisdale site represents a fluvio-deltaic or tidal-estuarine environment reminiscent of the modern Albemarle Sound, and thus has more of a terrestrial influence.

## Vertebrate paleobiota

Based on the Paleobiology Database:

### Cartilaginous fish

Cartilaginous fish of the Marshalltown Formation :
| Genus | Species | Member | Location | Material | Notes | Images |

### Bony fish

Based on:
Bony fish of the Marshalltown Formation :
| Genus | Species | Location | Notes |
| Acipenser | A. sp. | Ellisdale Site | A sturgeon. |
| Anomoeodus | A. phaseolus | Ellisdale Site, St. Georges | A pycnodont. |
| Atractosteus | A. sp. | Ellisdale Site | A gar. |
| Cyclurus | C. cf. fragosus | Ellisdale Site | An amiid related to bowfins. |
| cf. Cylindracanthus | C. sp. | St. George's | A fish of uncertain affinities. |
| Enchodus | E. ferox | Ellisdale Site, St. Georges | An enchodontid aulopiform. |
| Enchodus | E. sp. | St. Georges | An enchodontid aulopiform. |
| cf. Lepisosteus | L. sp. | St. Georges | A gar. |
| Paralbula | P. casei | Ellisdale Site, St. Georges | A phyllodontid elopomorph. |
| cf. "Platacodon" | P. sp. | Ellisdale Site | A sciaenid-like fish. |
| Stephanodus | S. sp. | St. Georges | A pycnodont. |
| Xiphactinus | X. audax | Ellisdale Site | An ichthyodectid. |
| Xiphactinus | X. sp. | St. Georges | An ichthyodectid. |

### Amphibians

Amphibians of the Marshalltown Formation :
| Genus | Species | Location | Notes |
| Albanerpetontidae indet. | | Ellisdale Site | An albanerpetontid. |
| Alytidae indet. | | Ellisdale Site | An alytid frog. |
| cf. Habrosaurus | H. sp. | Ellisdale Site | A sirenid salamander. |
| Parrisia | P. neocesariensis | Ellisdale Site | A batrachosauroidid salamander. Type locality of genus and species. |
| Pelobatidae indet. | | Ellisdale Site | A relative of European spadefoot toads. |
| cf. Proamphiuma | P. sp. | Ellisdale Site | A sirenid salamander. |
| cf. Scotiophryne | S. sp. | Ellisdale Site | A frog of uncertain affinities. |
| cf. Theatonius | T. sp. | Ellisdale Site | A frog of uncertain affinities. |

### Reptiles
#### Dinosaurs

Based on Brownstein (2018):
Dinosaurs of the Marshalltown Formation :
| Genus | Species | Location | Notes |
| "Coelosaurus" | C. antiquus | | An ornithomimosaur. |
| Coelurosauria indet. | | Ellisdale Site | A coelurosaur theropod of uncertain affinities. |
| Dromaeosauridae indet. | | Ellisdale Site | A dromaeosaurid theropod of uncertain affinities. |
| Dryptosaurus | D. sp. | Ellisdale Site | A tyrannosauroid theropod. Specimens from this formation might belong to Appalachiosaurus instead. |
| Hadrosauridae indet. | | Ellisdale Site | A hadrosaurid ornithopod. |
| ?Hadrosauroidea indet. | | Ellisdale Site | A hadrosauroid ornithopod. |
| Hadrosaurus | H. foulkii | Ellisdale Site | A hadrosaurid ornithopod. |
| Hadrosaurus | ?H. sp. | Ellisdale Site | A hadrosaurid ornithopod. |
| Hypsibema | H. crassicauda | Ellisdale Site | A hadrosauroid ornithopod. |
| Nodosauridae indet. | | Ellisdale Site | A nodosaurid ankyosaur. |
| Ornithopoda indet. | | Ellisdale Site | An ornithopod of uncertain affinities. |

#### Crocodilians

Crocodilians of the Marshalltown Formation :
| Genus | Species | Location | Notes |
| cf. "Allognathosuchus" | "A". sp. | Ellisdale Site | An alligatorid. |
| cf. Brachychampsa | B. sp. | Ellisdale Site | An alligatorid. |
| Deinosuchus | D. rugosus | Ellisdale Site | An alligatoroid, one of the largest known crocodilians. Remains of both juveniles and adults known. |
| "Diplocynodon" | "D". sp. | Ellisdale Site | An alligatorid. |
| "Leidyosuchus" | "L". sp. | Cambridge Crossing Executive Park | An alligatorid. |

#### Turtles

Turtles of the Marshalltown Formation :
| Genus | Species | Material | Notes |
| Adocus | A. beatus | Ellisdale Site | An adocid. |
| Chedighaii | C. barberi | Ellisdale Site | A bothremydid side-necked turtle. |
| Corsochelys | C. sp. | Ellisdale Site | A dermochelyid sea turtle. |
| Trionychidae indet. | | Ellisdale Site, St. Georges | A softshell turtle of uncertain affinities. |

#### Plesiosaurs

Plesiosaurs of the Marshalltown Formation :
| Genus | Species | Member | Location | Material | Notes | Images |
| "Elasmosaurus" | "E." orientalis | | Swedesboro | Two back vertebrae | An elasmosaurid, species name is a nomen dubium due to fragmentary nature. | |

#### Squamates

Squamates of the Marshalltown Formation :
| Genus | Species | Location | Notes |
| Clidastes | C. iguanavus | Swedesboro | A mosasaurine mosasaur. Type locality of species. |
| Clidastes | cf. C. sp. | St. Georges | A mosasaurine mosasaur. Type locality of species. |
| ?Contogenys | C. sp. | Ellisdale Site | A globaurid lizard. |
| cf. Globidens | G. sp. | St. Georges | A globidensine mosasaur. |
| Glyptosaurinae indet. | | Ellisdale Site | An anguid lizard. |
| cf. Halisaurus | H. sp. | Ellisdale Site | A halisaurine mosasaur. |
| Haptosphenus | H. sp. | Ellisdale Site | A chamopsid lizard. |
| cf. Odaxosaurus | O. sp. | Ellisdale Site | An anguid lizard. |
| cf. Machaerosaurus | M. sp. | Ellisdale Site | An anguid lizard. |
| Prototeius | P. stageri | Ellisdale Site | A chamopsid lizard. Type locality of genus and species. |

#### Choristodera

Choristoderes of the Marshalltown Formation :
| Genus | Species | Member | Location | Material | Notes | Images |
| Neochoristodera indet. | | | Ellisdale Site | 1 vertebra | A neochoristodere, one of the very few records of this group from eastern North America. | |

### Mammals

Based on Grandstaff et al (1992):
Mammals of the Marshalltown Formation :
| Genus | Species | Location | Notes |
| Cimolodontidae indet. | | Ellisdale Site | A cimolodontid multituberculate. |
| Cimolomys | C. cf. clarki | Ellisdale Site | A cimolomyid multiberculate. |
| cf. Didelphodon | D. sp. | Ellisdale Site | A stagodontid metatherian. |
| Protalphadon | P. lulli | Ellisdale Site | A metatherian. |