{{Short description|Geological Formation in the United States}} {{Infobox rockunit | name = Marshalltown Formation | image = | caption = | type = Geological formation | age = Middle to Late Campanian, {{fossil range|75|72}} | prilithology =Glauconite, sandstone | otherlithology =Siderite | namedfor =Marshalltown, New Jersey | namedby = | region =New Jersey, Delaware | country =United States | coordinates = | unitof =Monmouth Group | subunits = | underlies = Wenonah Formation | overlies = Englishtown Formation | thickness = | extent = | area = | map = | map_caption = |period=Campanian}}

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.<ref name="dinosaurdistribution">Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.</ref><ref>{{Cite web |title=Geolex — Marshalltown publications |url=https://ngmdb.usgs.gov/Geolex/UnitRefs/MarshalltownRefs_2656.html |access-date=2024-11-12 |website=ngmdb.usgs.gov}}</ref>

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.<ref name=":0">{{Cite web |title=PBDB Collection |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=14455 |access-date=2024-11-12 |website=paleobiodb.org}}</ref>

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.<ref name=":0" /><ref>{{Cite journal |last=Denton |first=Robert |date=2022-04-07 |title=ALBEMARLE SOUND NC - A MODERN ANALOG FOR THE ELLISDALE FOSSIL SITE (LATE CRETACEOUS, CAMPANIAN, NJ) |url=https://gsa.confex.com/gsa/2022NC/webprogram/Paper373518.html |journal=Geological Society of America Abstracts with Programs |language=English |publisher=GSA |volume=54 |issue=4|doi=10.1130/abs/2022NC-373518 |bibcode=2022GSAA...5473518D |url-access=subscription }}</ref>

== Vertebrate paleobiota == Based on the Paleobiology Database:<ref name=":1">{{Cite web |title=PBDB Collection |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=14455 |access-date=2025-01-18 |website=paleobiodb.org}}</ref><ref name=":2">{{Cite web |title=PBDB Collection |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=27570 |access-date=2025-01-18 |website=paleobiodb.org}}</ref>

=== Cartilaginous fish === {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Cartilaginous fish''' '''of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- | | | | | | | |}

=== Bony fish === Based on:<ref name=":1" /><ref name=":2" /> {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Bony fish of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- |''Acipenser'' |''A.'' sp. | |Ellisdale Site | |A sturgeon. |frameless |- |''Anomoeodus'' |''A. phaseolus'' | |Ellisdale Site, St. Georges | |A pycnodont. |frameless|154x154px |- |''Atractosteus'' |''A.'' sp. | |Ellisdale Site | |A gar. |frameless |- |''Cyclurus'' |''C.'' cf. ''fragosus'' | |Ellisdale Site | |An amiid related to bowfins. |frameless |- |cf. ''Cylindracanthus'' |''C.'' sp. | |St. George's | |A fish of uncertain affinities. |frameless |- | rowspan="2" |''Enchodus'' |''E. ferox'' | |Ellisdale Site, St. Georges | | rowspan="2" |An enchodontid aulopiform. | rowspan="2" |frameless |- |''E.'' sp. | |St. Georges | |- |cf. ''Lepisosteus'' |''L.'' sp. | |St. Georges | |A gar. |frameless |- |''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. | |- | rowspan="2" |''Xiphactinus'' |''X. audax'' | |Ellisdale Site | | rowspan="2" |An ichthyodectid. | rowspan="2" |frameless |- |''X.'' sp. | |St. Georges | |}

=== Amphibians === {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Amphibians of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- |Albanerpetontidae indet. | | | rowspan="8" |Ellisdale Site | |An albanerpetontid. | |- |Alytidae indet. | | | |An alytid frog. | |- |cf. ''Habrosaurus'' |''H.'' sp. | | |A sirenid salamander. |frameless |- |''Parrisia'' |''P. neocesariensis'' | | |A batrachosauroidid salamander. Type locality of genus and species.<ref>{{Cite journal |last1=Denton Jr. |first1=Robert K. |last2=O'Neill |first2=Robert C. |date=1998-09-15 |title=''Parrisia neocesariensis'', a new batrachosauroidid salamander and other amphibians from the Campanian of eastern North America |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.1998.10011076 |journal=Journal of Vertebrate Paleontology |volume=18 |issue=3 |pages=484–494 |doi=10.1080/02724634.1998.10011076 |bibcode=1998JVPal..18..484D |issn=0272-4634|url-access=subscription }}</ref> | |- |Pelobatidae indet. | | | |A relative of European spadefoot toads. | |- |cf. ''Proamphiuma'' |''P.'' sp. | | |A sirenid salamander. | |- |cf. ''Scotiophryne'' |''S.'' sp. | | |A frog of uncertain affinities. | |- |cf. ''Theatonius'' |''T.'' sp. | | |A frog of uncertain affinities. | |}

=== Reptiles ===

==== Dinosaurs ==== Based on Brownstein (2018):<ref>{{Cite journal |last=Brownstein |first=Chase D. |date=2018-02-08 |title=The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia |url=https://palaeo-electronica.org/content/2018/2123-appalachia-biogeography |journal=Palaeontologia Electronica |language=en |volume=21 |issue=1 |pages=1–56 |doi=10.26879/801 |issn=1094-8074 |doi-access=free}}</ref><ref>{{Cite journal |last=Brownstein |first=Chase D. |date=2018 |title=The distinctive theropod assemblage of the Ellisdale site of New Jersey and its implications for North American dinosaur ecology and evolution during the Cretaceous |journal=Journal of Paleontology |language=en |volume=92 |issue=6 |pages=1115–1129 |doi=10.1017/jpa.2018.42 |issn=0022-3360 |doi-access=free|bibcode=2018JPal...92.1115B }}</ref> {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Dinosaurs of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- |"''Coelosaurus''" |''C. antiquus'' | | | |An ornithomimosaur. |frameless |- |Coelurosauria indet. | | | rowspan="10" |Ellisdale Site | |A coelurosaur theropod of uncertain affinities. | |- |Dromaeosauridae indet. | | | |A dromaeosaurid theropod of uncertain affinities. | |- |''Dryptosaurus'' |''D.'' sp. | | |A tyrannosauroid theropod. Specimens from this formation might belong to ''Appalachiosaurus'' instead.<ref>{{Cite web |last=Mortimer |first=Mickey |date=2024 |title=Tyrannosauroidea |url=https://theropoddatabase.github.io/Tyrannosauroidea.html |access-date=Jan 28, 2025 |website=The Theropod Database}}</ref> |frameless |- |Hadrosauridae indet. | | | |A hadrosaurid ornithopod. | |- |?Hadrosauroidea indet. | | | |A hadrosauroid ornithopod. | |- | rowspan="2" |''Hadrosaurus'' |''H. foulkii'' | rowspan="2" | | | rowspan="2" |A hadrosaurid ornithopod. | rowspan="2" |frameless |- |?''H.'' sp. | |- |''Hypsibema'' |''H. crassicauda'' | | |A hadrosauroid ornithopod. |frameless |- |Nodosauridae indet. | | | |A nodosaurid ankyosaur. | |- |Ornithopoda indet. | | | |An ornithopod of uncertain affinities. | |} *

==== Crocodilians ==== {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Crocodilians''' '''of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- |cf. "''Allognathosuchus''" |''"A".'' sp. | |Ellisdale Site | |An alligatorid. | |- |cf. ''Brachychampsa'' |''B.'' sp. | |Ellisdale Site | |An alligatorid. |frameless |- |''Deinosuchus'' |''D. rugosus'' | |Ellisdale Site | |An alligatoroid, one of the largest known crocodilians. Remains of both juveniles and adults known.<ref>{{Cite journal |last=Brownstein |first=Chase Doran |date=2019-04-01 |title=First Record of a Small Juvenile Giant Crocodyliform and its Ontogenetic and Biogeographic Implications |url=https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-60/issue-1/014.060.0104/First-Record-of-a-Small-Juvenile-Giant-Crocodyliform-and-its/10.3374/014.060.0104.full |journal=Bulletin of the Peabody Museum of Natural History |volume=60 |issue=1 |pages=81 |doi=10.3374/014.060.0104 |bibcode=2019BPMNH..60...81B |issn=0079-032X|url-access=subscription }}</ref> |frameless |- |"''Diplocynodon''" |''"D".'' sp. | |Ellisdale Site | |An alligatorid. | |- |"''Leidyosuchus''" |''"L".'' sp. | |Cambridge Crossing Executive Park | |An alligatorid.<ref>{{Cite web |title=PBDB Collection |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=167663 |access-date=2025-01-18 |website=paleobiodb.org}}</ref> | |}

==== Turtles ==== {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Turtles of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- |''Adocus'' |''A. beatus'' | | |Ellisdale Site |An adocid. |frameless|156x156px |- |''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 ==== {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''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.<ref name=":3">{{Cite web |title=PBDB Collection |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=109662 |access-date=2025-01-18 |website=paleobiodb.org}}</ref> |frameless |}

==== Squamates ==== {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Squamates of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- | rowspan="2" |''Clidastes'' |''C. iguanavus'' | |Swedesboro | | rowspan="2" |A mosasaurine mosasaur. Type locality of species.<ref name=":3" /> | rowspan="2" |frameless |- |cf. ''C.'' sp. | |St. Georges | |- |?''Contogenys'' |''C.'' sp. | |Ellisdale Site | |A globaurid lizard. | |- |cf. ''Globidens'' |''G.'' sp. | |St. Georges | |A globidensine mosasaur. |frameless |- |Glyptosaurinae indet. | | |Ellisdale Site | |An anguid lizard. | |- |cf. ''Halisaurus'' |''H.'' sp. | |Ellisdale Site | |A halisaurine mosasaur. |frameless |- |''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.<ref>{{Cite journal |last1=Denton Jr. |first1=Robert K. |last2=O'Neill |first2=Robert C. |date=1995-06-13 |title=''Prototeius stageri'', Gen. et sp. Nov., a New Teiid Lizard from the Upper Cretaceous Marshalltown Formation of New Jersey, with a Preliminary Phylogenetic Revision of the Teiidae |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.1995.10011227 |journal=Journal of Vertebrate Paleontology |volume=15 |issue=2 |pages=235–253 |doi=10.1080/02724634.1995.10011227 |bibcode=1995JVPal..15..235D |issn=0272-4634|url-access=subscription }}</ref> | |}

==== Choristodera ==== {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''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.<ref>{{Cite journal |last1=Dudgeon |first1=Thomas W. |last2=Landry |first2=Zoe |last3=Callahan |first3=Wayne R. |last4=Mehling |first4=Carl M. |last5=Ballwanz |first5=Steven |date=2021 |title=An Appalachian population of neochoristoderes (Diapsida, Choristodera) elucidated using fossil evidence and ecological niche modelling |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/pala.12545 |journal=Palaeontology |language=en |volume=64 |issue=5 |pages=629–643 |doi=10.1111/pala.12545 |bibcode=2021Palgy..64..629D |issn=1475-4983|url-access=subscription }}</ref> | |}

=== Mammals === Based on Grandstaff ''et al'' (1992):<ref>{{Cite journal |last1=Grandstaff |first1=Barbara S. |last2=Parris |first2=David C. |last3=Robert K. Denton |first3=Jr. |last4=Gallagher |first4=William B. |date=1992 |title=Alphadon (Marsupialia) and Multituberculata (Allotheria) in the Cretaceous of Eastern North America |url=https://www.jstor.org/stable/4523441 |journal=Journal of Vertebrate Paleontology |volume=12 |issue=2 |pages=217–222 |doi=10.1080/02724634.1992.10011450 |jstor=4523441 |bibcode=1992JVPal..12..217G |issn=0272-4634|url-access=subscription }}</ref> {| class="wikitable" align="center" width="100%" ! colspan="8" align="center" |'''Mammals of the Marshalltown Formation''' |- !Genus !Species !Member !Location !Material !Notes !Images |- |Cimolodontidae indet. | | | rowspan="4" |Ellisdale Site | |A cimolodontid multituberculate. | |- |''Cimolomys'' |''C.'' cf. ''clarki'' | | |A cimolomyid multiberculate. |frameless |- |cf. ''Didelphodon'' |''D.'' sp. | | |A stagodontid metatherian. |frameless |- |''Protalphadon'' |''P. lulli'' | | |A metatherian. | |}

==See also== {{Portal|Earth sciences|Paleontology|Dinosaurs||}} * List of dinosaur-bearing rock formations ** List of stratigraphic units with few dinosaur genera

==Footnotes== {{Reflist}}

==References== * Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp.&nbsp;{{ISBN|0-520-24209-2}}.

Category:Campanian Stage Category:Cretaceous geology of New Jersey Category:Cretaceous Delaware

{{US-geologic-formation-stub}} Category:Deltaic deposits Category:Tidal deposits Category:Shallow marine deposits Category:Long stubs with short prose Category:Sandstone formations of the United States Category:Geologic formations of New Jersey Category:Geologic formations of Delaware