# List of the Mesozoic life of Montana

This list of the Mesozoic life of Montana contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of Montana and are between 252.17 and 66 million years of age.

## A

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* †Achelousaurus – type locality for genus
** †Achelousaurus horneri – type locality for species
* Life restoration of the Late Cretaceous dromaeosaurid ("raptor") Acheroraptor †Acheroraptor – type locality for genus
** †Acheroraptor temertyorum – type locality for species
* Acipenser
** †Acipenser eruciferus
* †Acristavus – type locality for genus
** †Acristavus gagslarsoni – type locality for species
* †Acrostichopteris
** †Acrostichopteris longipennis
* †Adiantites
** †Adiantites montanensis
* †Adocus
* †Albanerpeton
** †Albanerpeton nexuosus
* Life restoration of the Late Cretaceous horned dinosaur Albertaceratops †Albertaceratops
** †Albertaceratops nesmoi
* †Albertatherium
** †Albertatherium primus
* †Albertosaurus
* †Allocrioceras
** †Allocrioceras annulatum
* Life restoration of the Late Jurassic theropod dinosaur Allosaurus †Allosaurus
* †Alostera
** †Alostera saskatchewanensis
* †Alphadon
** †Alphadon attaragos
** †Alphadon halleyi – type locality for species
** †Alphadon marshi
** †Alphadon wilsoni
* †Altacreodus
** †Altacreodus magnus
* †Alzadasaurus – tentative report
* †Alzadites – type locality for genus
** †Alzadites alzadensis – type locality for species
* †Ambilestes
** †Ambilestes cerberoides – or unidentified comparable form
* Amia
** †Amia fragosa
** †Amia uintaensis
* †Amphicoelias
* †Anatotitan
** †Anatotitan copei
* †Anchura – tentative report
* Life restoration of the Late Cretaceous armored dinosaur Ankylosaurus †Ankylosaurus – type locality for genus
** †Ankylosaurus magniventris – type locality for species
* †Anomozamites
* †Aquiladelphis
** †Aquiladelphis incus
** †Aquiladelphis minor
* †Aquilapollenites
** †Aquilapollenites collaris
** †Aquilapollenites conatus
** †Aquilapollenites marmarthensis
** †Aquilapollenites mtchedlishvilii
** †Aquilapollenites quadrilobus
** †Aquilapollenites turbidus
* Life restoration of the Early Cretaceous primitive horned dinosaur Aquilops †Aquilops – type locality for genus
** †Aquilops americanus – type locality for species
* Aralia – or unidentified comparable form
** †Aralia wellingtonia
* †Araliaephyllum
** †Araliaephyllum westonii
* †Araliopsoides
** †Araliopsoides cretacea – or unidentified comparable form
* †Araucarites
** †Araucarites longifolia
* †Arcellites
* †Archaeolamna
** †Archaeolamna kopingensis
* †Archaeotriakis – type locality for genus
** †Archaeotriakis rochelleae – type locality for species
* Fossilized shells of the Middle Jurassic ammonoid cephalopod Arcticoceras †Arcticoceras – tentative report
* †Arctocephalites
** †Arctocephalites gracilis – or unidentified comparable form
** †Arctocephalites maculatus – or unidentified comparable form
** †Arctocephalites platynotus – or unidentified comparable form
** †Arctocephalites sawtoothensis
** †Arctocephalites saypoensis
* †Argaliatherium – type locality for genus
** †Argaliatherium robustum – type locality for species
* †Ariadnaesporites
** †Ariadnaesporites fluviatilis – type locality for species
* †Ascarinites – type locality for genus
** †Ascarinites communis – type locality for species
* †Aspideretoides
* †Aspidophyllum – or unidentified comparable form
** †Aspidophyllum trilobatum
* †Asplenium
* Shell of a modern Astarte bivalve Astarte
** †Astarte meeki
** †Astarte morion
** †Astarte packardi – or unidentified comparable form
* †Athrotaxites
** †Athrotaxites berryi – or unidentified comparable form
* †Aublysodon
** †Aublysodon mirandus
* †Austrotindaria
** †Austrotindaria canalensis
** †Austrotindaria svalbardensis
* †Avaceratops – type locality for genus
** †Avaceratops lammersi – type locality for species
* Avicula
* Life restoration of the Late Cretaceous toothed bird Avisaurus with prey †Avisaurus – type locality for genus
** †Avisaurus archibaldi – type locality for species
** †Avisaurus gloriae – type locality for species
* †Axestemys
** †Axestemys splendida – type locality for species
* Azolla
** †Azolla barbata
** †Azolla circinata – type locality for species
** †Azolla distincta
** †Azolla simplex – type locality for species
** †Azolla spinata – type locality for species
* †Azollopsis – type locality for genus
** †Azollopsis coccoides – type locality for species
** †Azollopsis tomentosa – type locality for species

## B

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* †Baculatisporites
* Fossilized shell of the Late Cretaceous ammonoid cephalopod Baculites †Baculites
** †Baculites asper
** †Baculites codyensis
** †Baculites compressus
** †Baculites mariasensis
* †Baena
** †Baena callosa – type locality for species
* †Baioconodon
** †Baioconodon nordicus – or unidentified comparable form
* †Bakevellia
* Diagram of the known fossil material of the Late Cretaceous dromaeosaurid ("raptor") Bambiraptor †Bambiraptor – type locality for genus
** †Bambiraptor feinbergi – type locality for species
* Barbourula – or unidentified comparable form
* †Basilemys
** †Basilemys sinuosa – type locality for species
* †Batodon
** †Batodon tenuis
* †Belfria – type locality for genus
** †Belfria microphylla – type locality for species
* Fossilized skeleton of the Late Cretaceous bony fish Belonostomus †Belonostomus
** †Belonostomus longirostris
* †Bernissartia
* †Biretisporites
** †Biretisporites deltoideus
* †Borealosuchus
** †Borealosuchus sternbergii
* †Boremys
** †Boremys pulchra
* †Borissiakoceras
** †Borissiakoceras orbiculatum
* Brachaelurus
** †Brachaelurus estesi
* †Brachyceratops – type locality for genus
** †Brachyceratops montanensis – type locality for species
* †Brachychampsa – type locality for genus
** †Brachychampsa montana – type locality for species
** †Brachychampsa montanus
* Fossilized natural mummy of the Late Cretaceous duck-billed dinosaur Brachylophosaurus †Brachylophosaurus
** †Brachylophosaurus canadensis – type locality for species
* †Buccinammonites – type locality for genus
** †Buccinammonites minimus – type locality for species

## C

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* Life restoration of a herd of the Late Jurassic sauropod dinosaur Camarasaurus †Camarasaurus
* Campeloma
* †Camptonectes
** †Camptonectes platessiformis
** †Camptonectes stygius
* Carcharias
* †Cardiaster
** †Cardiaster curtus
* †Carinalestes – type locality for genus
** †Carinalestes murensis – type locality for species
* †Cedrobaena
** †Cedrobaena brinkman
* †Celastrophyllum – or unidentified comparable form
* Life restoration of the Late Cretaceous horned dinosaur Centrosaurus †Centrosaurus
* †Cerasinops – type locality for genus
** †Cerasinops hodgskissi – type locality for species
* †Ceratodus
** †Ceratodus frazieri
** †Ceratodus guentheri – or unidentified comparable form
* †Ceratops – type locality for genus
** †Ceratops montanus – type locality for species
* †Cerberophis – type locality for genus
** †Cerberophis robustus – type locality for species
* †Cercomya
** †Cercomya punctata
* †Chamops
** †Chamops segnis
* †Champsosaurus
** †Champsosaurus natator
* Life restoration of the Late Cretaceous horned dinosaur Chasmosaurus †Chasmosaurus – or unidentified comparable form
* Chiloscyllium
** †Chiloscyllium missouriensis – type locality for species
* †Chirostenotes
** †Chirostenotes elegans
* Chlamys
* †Chondroceras
** †Chondroceras allani – or unidentified comparable form
** †Chondroceras oblatum
* †Cimexomys
** †Cimexomys minor
* †Cimolestes
** †Cimolestes incisus
** †Cimolestes stirtoni
* †Cimoliasaurus
* †Cimolodon
** †Cimolodon nitidus
* Life restoration of the face of the Late Cretaceous multituberculate mammal Cimolomys †Cimolomys
** †Cimolomys clarki – type locality for species
** †Cimolomys gracilis
* †Cimolopteryx
** †Cimolopteryx maxima
* †Cinnamomoides
* Cladophlebis
** †Cladophlebis alberta
** †Cladophlebis constricta
** †Cladophlebis heterophylla
** †Cladophlebis inclinata
** †Cladophlebis oblongifolia
** †Cladophlebis oerstedi
** †Cladophlebis virginiensis
* †Claosaurus
* †Claraia
** †Claraia aurita
** †Claraia clarai
** †Claraia mulleri
** †Claraia stachei
* Life restoration of the Late Cretaceous mosasaurid Clidastes †Clidastes
* †Clioscaphites
** †Clioscaphites vermiformis
* †Cobbanites
* †Coelostylina
* †Colpodontosaurus
** †Colpodontosaurus cracens
* †Componocancer
** †Componocancer roberti
* †Compsemys
** †Compsemys victa
* †Coniophis
** †Coniophis precedens
* †Coniopteris
** †Coniopteris bella – or unidentified comparable form
** †Coniopteris hymenophylloides
** †Coniopteris simplex
* †Continuoolithus
** †Continuoolithus canadensis
* †Contogenys – type locality for genus
** †Contogenys sloani – type locality for species
* †Coriops
** †Coriops amnicolus
* †Corviconodon
** †Corviconodon montanensis – type locality for species
* Mounted fossilized skeleton of the Late Cretaceous duck-billed dinosaur Corythosaurus †Corythosaurus
** †Corythosaurus casuarius
* Crassatella
* †Cremnoceramus
** †Cremnoceramus deformis
* †Cretolamna
** †Cretolamna appendiculata
* †Cretorectolobus – type locality for genus
** †Cretorectolobus olsoni – type locality for species
* †Crocodilus
** †Crocodilus humilis
* †Cryptometoicoceras
** †Cryptometoicoceras mite
* Cucullaea
** †Cucullaea haguei
** †Cucullaea rockymontana
* †Cyathidites
** †Cyathidites minor
* †Cycadolepis
* †Cycadopites
** †Cycadopites fragilis
* †Cyclurus
** †Cyclurus fragosus

## D

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* †Daspletosaurus
** †Daspletosaurus horneri – type locality for species
* †Deinodon – type locality for genus
** †Deinodon horridus – type locality for species
* Life restoration of the Early Cretaceous dromaeosaur ("raptor") Deinonychus †Deinonychus – type locality for genus
** †Deinonychus antirrhopus – type locality for species
* †Deinosuchus – type locality for genus
** †Deinosuchus rugosus – type locality for species
* †Deltoidospora
** †Deltoidospora cascadensis – type locality for species
** †Deltoidospora diaphana
** †Deltoidospora hallii – type locality for species
* Dentalium
* †Derrisemys
** †Derrisemys sterea
* †Diclonius
* †Dictyothykalos
* Mounted fossilized skeleton of the Late Cretaceous marsupial relative Didelphodon †Didelphodon
** †Didelphodon vorax
* †Didymoceras
** †Didymoceras cheyennense
** †Didymoceras nebrascense
** †Didymoceras stevensoni
* †Diettertia
** †Diettertia montanensis
* Life restoration of the Late Jurassic long-necked dinosaur Diplodocus †Diplodocus
* †Doratodon – or unidentified comparable form
* †Dromaeosaurus
** †Dromaeosaurus albertensis
* †Dryophyllum – report made of unidentified related form or using admittedly obsolete nomenclature
** †Dryophyllum subfalcatum
* †Dunveganoceras
** †Dunveganoceras albertense
** †Dunveganoceras parvum – type locality for species
** †Dunveganoceras pondi
* †Dyadonapites
** †Dyadonapites reticulatus
* Illustration of the fossilized pelvis and tail of the Late Cretaceous armored dinosaur Dyoplosaurus †Dyoplosaurus
** †Dyoplosaurus acutosquameus

## E

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* †Echinatisporis
* †Ectocentrocristus
** †Ectocentrocristus foxi – type locality for species
* †Ectoconodon
** †Ectoconodon montanensis – type locality for species
* †Edgarosaurus
** †Edgarosaurus muddi
* †Edmontonia
** †Edmontonia longiceps
** †Edmontonia rugosidens – type locality for species
* †Edmontosaurus
** Life restoration of the Late Cretaceous duck-billed dinosaur Edmontosaurus annectens †Edmontosaurus annectens
* †Einiosaurus – type locality for genus
** †Einiosaurus procurvicornis – type locality for species
* †Elasmodus
** †Elasmodus greenoughi – or unidentified comparable form
* †Emarginachelys – type locality for genus
** †Emarginachelys cretacea – type locality for species
* †Entolioides
** †Entolioides utahensis
* †Eodelphis
* †Eopelobates – or unidentified comparable form
* A living Equisetum, or horsetail †Equisetum
** †Equisetum cascadensis – type locality for species
** †Equisetum laterale
** †Equisetum montanensis
* †Erdtmanipollis
** †Erdtmanipollis procumbentiformis
* †Essonodon – type locality for genus
** †Essonodon browni – type locality for species
* †Eubaena
** †Eubaena cephalica
* †Eucrossorhinus
** †Eucrossorhinus microcuspidatus – type locality for species
* †Eumorphotis
** †Eumorphotis amplicostata – type locality for species
** †Eumorphotis ericius – or unidentified comparable form
** †Eumorphotis multiformis
* †Euomphaloceras
** †Euomphaloceras septemseriatum
* Life restoration of the Late Cretaceous armored dinosaur Euoplocephalus †Euoplocephalus
** †Euoplocephalus tutus
* †Eutrephoceras
** †Eutrephoceras montanensis – type locality for species
* †Exiteloceras
** †Exiteloceras jenneyi
* †Exogyra
** †Exogyra columbella
* †Exostinus
** †Exostinus lancensis

## F

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* †Falepetrus
** †Falepetrus barwini
* Ficus – or unidentified comparable form
** †Ficus ovatifolia
* †Fletcherithyris – report made of unidentified related form or using admittedly obsolete nomenclature
** †Fletcherithyris margaritovi
* †Foraminisporis
** †Foraminisporis undulates

## G

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* †Gastopoda
* †Gervillia
** †Gervillia ussurica – or unidentified comparable form
* †Gilmoremys
** †Gilmoremys lancensis
* Fossilized leaf of the Permian-modern tree Ginkgo Ginkgo
** †Ginkgo pluripartita
* †Ginkgoites
** †Ginkgoites cascadensis
** †Ginkgoites pluripartita
* †Glasbius
** †Glasbius twitchelli – type locality for species
* †Glishades – type locality for genus
** †Glishades ericksoni – type locality for species
* †Glyptops
** †Glyptops pervicax – type locality for species
* Glyptostrobus – or unidentified comparable form
* Mounted fossilized skeleton of the Middle Jurassic-Late Cretaceous mammal Gobiconodon †Gobiconodon – type locality for genus
** †Gobiconodon ostromi – type locality for species
* †Goniobasis
** †Goniobasis subtortuosa
* †Gorgosaurus
** †Gorgosaurus libratus – type locality for species
* †Grammatodon
* †Grewipollenites
** †Grewipollenites radiatus
* Interior and exterior of a fossilized shell of the Late Triassic-Eocene marine bivalve Gryphaea †Gryphaea
** †Gryphaea – type locality for species – informal
** †Gryphaea impressimarginata
* †Gryposaurus
** †Gryposaurus latidens – type locality for species
** †Gryposaurus notabilis
* †Gypsonictops
** †Gypsonictops hypoconus
** †Gypsonictops illuminatus
** †Gypsonictops lewisi – type locality for species
* Gyrodes
** †Gyrodes conradi

## H

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* †Habrosaurus
** †Habrosaurus dilatus
* †Hadrosaurus
** †Hadrosaurus breviceps – type locality for species
** †Hadrosaurus paucidens – type locality for species
* †Hamites
** †Hamites cimarronensis
* †Haptosphenus
** †Haptosphenus placodon
* †Hausmannia
** †Hausmannia fisheri
** †Hausmannia montanensis
* †Helopanoplia
** †Helopanoplia distincta
* Life restoration of the Late Cretaceous toothed bird Hesperornis †Hesperornis
** †Hesperornis montana – type locality for species
* †Heteropecten – tentative report
* †Holocrinus
* †Hoploscaphites
** †Hoploscaphites macer – type locality for species
* †Hummelichelys
** †Hummelichelys beecheri
** †Hummelichelys foveatus – type locality for species
* †Hybodus
** †Hybodus montanensis – type locality for species
** †Hybodus storeri – type locality for species
* †Hypacrosaurus
** †Hypacrosaurus stebingeri – type locality for species
* †Hypotodus
** †Hypotodus grandis – type locality for species

## I

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* †Idiohamites
** †Idiohamites bispinosus – type locality for species
** †Idiohamites pulchellus – type locality for species
* Fossilized shell of the Early Jurassic-Late Cretaceous marine bivalve Inoceramus with a human indicating its size †Inoceramus
** †Inoceramus arnoldi
** †Inoceramus canaliculatus
** †Inoceramus cancellatus
** †Inoceramus cardissoides - or unidentified loosely related form
** †Inoceramus cordiformis – or unidentified comparable form
** †Inoceramus erectus
** †Inoceramus fragilis – or unidentified related form
** †Inoceramus frechi – or unidentified comparable form
** †Inoceramus gibbosus
** †Inoceramus gilli – type locality for species
** †Inoceramus glacierensis – type locality for species
** †Inoceramus koeneni
** †Inoceramus latisulcatus – or unidentified comparable form
** †Inoceramus lesginensis
** †Inoceramus lingua – or unidentified comparable form
** †Inoceramus lundbreckensis
** †Inoceramus sokolovi – type locality for species
** †Inoceramus undabundus
** †Inoceramus walterdorfensis
* †Iqualadelphis
** †Iqualadelphis lactea
* Fossilized skeleton of the Middle Jurassic-Miocene Chimaera relative Ischyodus †Ischyodus
** †Ischyodus bifurcatus
* †Ischyrhiza
** †Ischyrhiza avonicola
** †Ischyrhiza mira
* †Isocyprina – or unidentified comparable form
** †Isocyprina iddingsi

## J

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* Life restoration of the Late Cretaceous horned dinosaur Judiceratops †Judiceratops – type locality for genus
** †Judiceratops tigris – type locality for species
* †Judithemys
** †Judithemys backmani

## K

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* †Kastanoceras – type locality for genus
** †Kastanoceras spiniger – type locality for species
* †Klukia
** †Klukia canadensis
* Life restoration of the Late Cretaceous duck-billed dinosaur Kritosaurus †Kritosaurus
** †Kritosaurus breviceps – or unidentified comparable form
* †Krokolithes

## L

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* †Labrodioctes – type locality for genus
** †Labrodioctes montanensis – type locality for species
* †Laevigatosporites
** †Laevigatosporites haardtii
* Fossilized skeleton of the Early Jurassic-Late Cretaceous bony fish Lepidotes †Lepidotes
** †Lepidotes haydeni – type locality for species
** †Lepidotes occidentalis – type locality for species
* †Lepismatina – report made of unidentified related form or using admittedly obsolete nomenclature
** †Lepismatina mansfieldi
* Lepisosteus
** †Lepisosteus occidentalis
* †Leptalestes
** †Leptalestes cooki
** †Leptalestes krejcii
** †Leptalestes prokrejcii
** †Leptalestes toevsi – type locality for species
* Life restoration of the Late Cretaceous primitive horned dinosaur Leptoceratops †Leptoceratops
** †Leptoceratops gracilis
* †Leptochamops
** †Leptochamops denticulatus
* †Leptochondria
** †Leptochondria occidanea
* †Leptopecopites
** †Leptopecopites pocockii
* †Leptorhynchos – tentative report
* †Lesterwardia – type locality for genus
** †Lesterwardia palustris – type locality for species
* †Liliacidites
* †Lingula
* †Lingularia
** †Lingularia borealis
* †Lioplacodes
** †Lioplacodes judithensis
** †Lioplacodes williamsi
* †Liostrea
** †Liostrea strigilecula
* †Lisserpeton – type locality for genus
** †Lisserpeton atlantes
** †Lisserpeton bairdi – type locality for species
* †Lonchidion
** †Lonchidion selachos
* Fossilized shell of the Triassic-modern marine bivalve Lopha Lopha
* †Lucina
* Lunatia
** †Lunatia dakotensis – or unidentified comparable form
* †Lygobius – type locality for genus
** †Lygobius knowltoni – type locality for species

## M

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* †Magadiceramus
** †Magadiceramus soukupi
* †Magnuviator – type locality for genus
** †Magnuviator ovimonsensis – type locality for species
* †Maiasaura – type locality for genus
** †Maiasaura peeblesorum – type locality for species
* †Marchantiolites
** †Marchantiolites blairmorensis
* †Marmarthia
** †Marmarthia trivialis
* †Medusaceratops – type locality for genus
** †Medusaceratops lokii – type locality for species
* †Meleagrinella
** †Meleagrinella curta
* †Melvius – type locality for genus
** †Melvius thomasi – type locality for species
* †Meniscoessus
** †Meniscoessus major
** †Meniscoessus robustus – type locality for species
* †Meniscognathus
** †Meniscognathus altmani
* Life restoration of the Late Cretaceous horned dinosaur Mercuriceratops †Mercuriceratops – type locality for genus
** †Mercuriceratops gemini – type locality for species
* †Mesodma
** †Mesodma formosa
** †Mesodma hensleighi
** †Mesodma primaeva
** †Mesodma thompsoni
* †Metoicoceras
** †Metoicoceras geslinianum
** †Metoicoceras mosbyense – type locality for species
** †Metoicoceras muelleri
* †Metzgeriites
** †Metzgeriites montanensis – type locality for species
* †Micrabacia
** †Micrabacia radiata
* †Microsulcatoceras – type locality for genus
** †Microsulcatoceras puzosiiforme – type locality for species
* Life restoration of the Early Cretaceous oviraptorosaur Microvenator †Microvenator – type locality for genus
** †Microvenator celer – type locality for species
* †Minerisporites
** †Minerisporites pseudorichardsonii
* †Miocidaris
* †Modiolus
** †Modiolus rosii
* †Monoclonius – type locality for genus
** †Monoclonius crassus – type locality for species
** †Monoclonius recurvicornis – type locality for species
** †Monoclonius sphenocerus – type locality for species
* †Monosulcites
** †Monosulcites riparius
* †Montanalestes
** †Montanalestes keeblerorum
* Mounted fossilized skeletons of the Late Cretaceous pterosaur Montanazhdarcho †Montanazhdarcho – type locality for genus
** †Montanazhdarcho minor – type locality for species
* †Montania – type locality for genus
** †Montania glandulosa – type locality for species
* †Montanoceratops
** †Montanoceratops cerorhynchus – type locality for species
* †Montanoolithus – type locality for genus
** †Montanoolithus strongorum – type locality for species
* †Moremanoceras
** †Moremanoceras costatum
** †Moremanoceras montanaense – type locality for species
** †Moremanoceras straini
* †Mosasaurus
** †Mosasaurus missouriensis
* †Myalina
** †Myalina postcarbonica
* †Myledaphus
** †Myledaphus bipartitus
* Shells washed ashore of Mytilus mussels †Mytilus

## N

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Nannometoicoceras
** †Nannometoicoceras nanos – type locality for species
* Fossilized skull of the Late Cretaceous tyrannosaur Nanotyrannus, possibly a juvenile Tyrannosaurus rather than a distinct genus †Nanotyrannus
** †Nanotyrannus lancensis – type locality for species
* †Naomichelys – type locality for genus
** †Naomichelys speciosa – type locality for species
* †Necrocarcinus
* †Nelumbo
** †Nelumbo peltata – type locality for species
* †Neocardioceras
** †Neocardioceras juddii
** †Neocardioceras minutum
* †Neogastroplites
** †Neogastroplites haasi
* †Neoplagiaulax
** †Neoplagiaulax burgessi – type locality for species
* †Neoschizodus
* †Neurankylus – type locality for genus
** †Neurankylus eximius – type locality for species
* †Nezpercius – type locality for genus
** †Nezpercius dodsoni – type locality for species
* †Nidimys – type locality for genus
** †Nidimys occultus – type locality for species
* †Nilsonia
** †Nilsonia compta – or unidentified comparable form
* †Normannites – tentative report
** †Normannites crickmayi – or unidentified comparable form
* †Nortedelphys – type locality for genus
** †Nortedelphys jasoni – type locality for species
** †Nortedelphys minimus – type locality for species
* Fossilized skeleton of the Late Cretaceous-Eocene bony fish Notogoneus †Notogoneus
** †Notogoneus montananesis – type locality for species
** †Notogoneus montenensis – type locality for species
* Nucula
* †Nymphaeites

## O

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Obamadon – type locality for genus
** †Obamadon gracilis – type locality for species
* †Odaxosaurus
** †Odaxosaurus piger
* Odontaspis
** †Odontaspis sanguinei – type locality for species
* †Oklatheridium
** †Oklatheridium wiblei – type locality for species
* †Onchosaurus
** †Onchosaurus avonicolus
* Fossilized partial cranium of the Late Cretaceous armored dinosaur Oohkotokia †Oohkotokia – type locality for genus
** †Oohkotokia horneri – type locality for species
* †Ophioglypha
** †Ophioglypha bridgerensis
* †Ophiomorpha
* †Opisthotriton
** †Opisthotriton kayi
* †Orbicoelia
* †Ornithomimus
** †Ornithomimus grandis – type locality for species
** †Ornithomimus tenuis – type locality for species
* †Orodromeus – type locality for genus
** †Orodromeus makelai – type locality for species
* Life restoration of the Late Cretaceous herbivorous dinosaur Oryctodromeus in a burrow †Oryctodromeus – type locality for genus
** †Oryctodromeus cubicularis – type locality for species
* Ostrea
* †Oxybeloceras
** †Oxybeloceras crassum
* †Oxytoma
** †Oxytoma mclearni

## P

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* Life restoration of subadults of the Late Cretaceous dome-headed dinosaur Pachycephalosaurus butting heads †Pachycephalosaurus – type locality for genus
** †Pachycephalosaurus wyomingensis – type locality for species
* †Pagiophyllum
* †Palaeobatrachus
** †Palaeobatrachus occidentalis
* †Palaeolabrus
** †Palaeolabrus montanensis
* †Palaeosaniwa
** †Palaeosaniwa canadensis
* †Palaeoscincus – type locality for genus
** †Palaeoscincus costatus – type locality for species
* †Palatobaena
** †Palatobaena bairdi
* †Paleopsephurus – type locality for genus
** †Paleopsephurus wilsoni – type locality for species
* †Paleoungulatum – type locality for genus
** †Paleoungulatum hooleyi – type locality for species
* Illustration of a fossilized skull of the Late Cretaceous armored dinosaur Panoplosaurus †Panoplosaurus
* †Pappotherium
** †Pappotherium pattersoni
* †Parachondroceras
** †Parachondroceras andrewsi
** †Parachondroceras filicostatum
* †Paracimexomys
** †Paracimexomys judithae – type locality for species
** †Paracimexomys magnus – type locality for species
** †Paracimexomys priscus
** †Paracimexomys propriscus – type locality for species
** †Paracimexomys robisoni – or unidentified comparable form
* †Paraderma
** †Paraderma bogerti
* †Paralbula
** †Paralbula casei
* †Paramacellodus – or unidentified comparable form
** †Paramacellodus keebleri – type locality for species
* †Paranecturus – type locality for genus
** †Paranecturus garbanii – type locality for species
* †Paranyctoides
** †Paranyctoides maleficus
* Fossilized shell of the Late Cretaceous ammonoid cephalopod Parapuzosia with a human indicating its size †Parapuzosia
** †Parapuzosia bradyi – type locality for species
* †Parasaniwa
** †Parasaniwa wyomingensis
* †Parataxodium
* †Parazolla – type locality for genus
** †Parazolla heterotricha – type locality for species
* †Parazollopsis – type locality for genus
** †Parazollopsis cascadensis – type locality for species
* †Paronychodon
** †Paronychodon lacustris
* Micrograph of a fossilized tooth of the Late Cretaceous troodontid Pectinodon †Pectinodon – or unidentified comparable form
* †Pediomys
** †Pediomys elegans
* †Peneteius – type locality for genus
** †Peneteius aquilonius – type locality for species
* †Penetetrapites
** †Penetetrapites inconspicuous
* †Pentacrinus
** †Pentacrinus asteriscus
* †Permophorus
** †Permophorus triassicus
* †Phelopteria
* Pholadomya
** †Pholadomya inaequiplicatus
** †Pholadomya kingi
* Shells in differing orientations of Physa freshwater bladder snails Physa
** †Physa copei – or unidentified comparable form
* †Piceoerpeton
** †Piceoerpeton naylori – type locality for species
* †Piksi – type locality for genus
** †Piksi barbarulna – type locality for species
* †Pinna
** †Pinna kingi
* †Pistia
** †Pistia corrugata
* †Pityocladus
* †Pityophyllum
** †Pityophyllum lindstromi
* †Pityosporites
** †Pityosporites constrictus
* †Placunopsis
* †Plastomenus
** †Plastomenus costatus
* †Platacodon
** †Platacodon nanus
* †Platanophyllum
* †Plesiacanthoceras
** †Plesiacanthoceras wyomingense
* †Plesiacanthoceratoides
** †Plesiacanthoceratoides alzadense
* †Plesiobaena
** †Plesiobaena antiqua
* †Pleuromya
** †Pleuromya oblongata – or unidentified comparable form
** †Pleuromya subcompressa
* †Pleuronautilus
* †Pleuronectites – tentative report
* †Plicatolamna
** †Plicatolamna arcuata
* †Podozamites
** †Podozamites lanceolatus
* †Polycingulatisporites
** †Polycingulatisporites reduncus
* Mounted fossilized skeleton of the Late Cretaceous primitive horned dinosaur Prenoceratops †Prenoceratops – type locality for genus
** †Prenoceratops pieganensis – type locality for species
* †Prismatoolithus
** †Prismatoolithus hirschi – type locality for species
** †Prismatoolithus levis
* †Pristinuspollenites
** †Pristinuspollenites microsaccus
* †Proamphiuma
** †Proamphiuma cretacea
* †Procerberus
* †Prodesmodon
** †Prodesmodon copei
* †Promyalina
** †Promyalina spathi – type locality for species
* Mounted fossilized skeleton of the Late Cretaceous duck-billed dinosaur Prosaurolophus †Prosaurolophus
** †Prosaurolophus blackfeetensis – type locality for species
* †Protalphadon
** †Protalphadon foxi – type locality for species
** †Protalphadon lulli
* †Protexanites
* †Protocaiman
* †Protocardia
** †Protocardia schucherti
* †Protolambda
** †Protolambda mcgilli – type locality for species
** †?Protolambda clemensi – type locality for species
** †Protolambda florencae
** †Protolambda hatcheri
* †Protolamna
** †Protolamna sokolovi
* †Protophyllocladus
** †Protophyllocladus subintegrifolius
* †Protophyllum – or unidentified comparable form
* †Protoplatyrhina – type locality for genus
** †Protoplatyrhina renae – type locality for species
* †Protoscaphirhynchus – type locality for genus
** †Protoscaphirhynchus squamosus – type locality for species
* Fossilized mandible of the Late Cretaceous-Paleocene mammal Protungulatum †Protungulatum
** †Protungulatum coombsi – type locality for species
** †Protungulatum gorgun
* †Psammorhynchus
** †Psammorhynchus longipinnis – type locality for species
* †Pseudocycas
** †Pseudocycas douglasii – type locality for species
* †Pseudohypolophus
* †Pseudomelania
** †Pseudomelania hendricksoni
* †Pteria – tentative report
** †Pteria ussurica – or unidentified comparable form
* †Pteropelyx – type locality for genus
** †Pteropelyx grallipes – type locality for species
* †Ptychotrygon
** †Ptychotrygon blainensis – type locality for species
** †Ptychotrygon hooveri
** †Ptychotrygon triangularis
* Assemblage of fossilized shells of the Cretaceous-Pleistocene oyster Pycnodonte Pycnodonte

## Q

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Quenstedtia – tentative report
* Quercus – report made of unidentified related form or using admittedly obsolete nomenclature
** †Quercus stantoni
* Life restoration of a flock of the Late Cretaceous pterosaur Quetzalcoatlus feeding on the ground †Quetzalcoatlus – or unidentified comparable form

## R

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Retinovena – type locality for genus
** †Retinovena fluvialis – type locality for species
* †Retitricolpites
** †Retitricolpites microreticulatus
* Rhabdocolpus
* †Rhaeboceras
** †Rhaeboceras burkholderi – type locality for species
** †Rhaeboceras cedarense – type locality for species
** †Rhaeboceras coloradoense
** †Rhaeboceras halli
** †Rhaeboceras subglobosum
* †Rhamnus – report made of unidentified related form or using admittedly obsolete nomenclature
** †Rhamnus cleburni
* †Richardoestesia
** †Richardoestesia gilmorei
** †Richardoestesia isosceles
* †Rostellites – tentative report
* Life restoration of the Late Cretaceous horned dinosaur Rubeosaurus †Rubeosaurus
** †Rubeosaurus ovatus – type locality for species
* †Rugocaudia – type locality for genus
** †Rugocaudia cooneyi – type locality for species

## S

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Sagenopteris
** †Sagenopteris elliptica
** †Sagenopteris mclearni
** †Sagenopteris williamsii
* Life restoration of the Early Cretaceous armored dinosaurs Sauropelta †Sauropelta – type locality for genus
** †Sauropelta edwardsorum – type locality for species
* †Saurornitholestes
** †Saurornitholestes langstoni
* †Scabrastephanocolpites
** †Scabrastephanocolpites lepidus
* †Scapherpeton
** †Scapherpeton tectum
* †Scaphites
** †Scaphites impendicostatus
** †Scaphites mariasensis
** †Scaphites preventricosus
** †Scaphites ventricosus
* †Scaphotrigonia
** †Scaphotrigonia naviformis
* †Schizolepis
* †Schizosporis
** †Schizosporis laevigatus
* †Sciponoceras
** †Sciponoceras gracile
* †Scollardius
** †Scollardius propalaeoryctes
* Fossilized cranium in multiple views of the Late Cretaceous armored dinosaur Scolosaurus †Scolosaurus
** †Scolosaurus cutleri
* †Scotiophryne – type locality for genus
** †Scotiophryne pustulosa – type locality for species
* †Sequoia
* †Siberiapollis
** †Siberiapollis montanensis
* †Sohlites
** †Sohlites spinosus
* †Solenoceras
** †Solenoceras bearpawense
* †Spalacotheridium
** †Spalacotheridium mckennai
* Sphaerium
** †Sphaerium planum
* †Sphaerotholus
** †Sphaerotholus buchholtzae – type locality for species
* †Sphenopteris
** †Sphenopteris brulensis
** †Sphenopteris geopperti
** †Sphenopteris goepperti
** †Sphenopteris latiloba
** †Sphenopteris mclearni
* †Spheroolithus
** †Spheroolithus albertensis
** †Spheroolithus choteauensis – type locality for species
** †Spheroolithus maiasauroides
* Life restoration of the Late Cretaceous horned dinosaur Spiclypeus †Spiclypeus – type locality for genus
** †Spiclypeus shipporum – type locality for species
* †Spiriferina – report made of unidentified related form or using admittedly obsolete nomenclature
* †Sporonites
** †Sporonites montanensis – type locality for species
* Squalicorax
** †Squalicorax kaupi
** †Squalicorax pristodontus
* †Squatirhina
** †Squatirhina americana
* †Stantoniella – type locality for genus
** †Stantoniella cretacea – type locality for species
* †Stegoceras
** †Stegoceras validum
* Restoration of the Late Jurassic stegosaur Stegosaurus †Stegosaurus
* †Stemmatoceras
** †Stemmatoceras albertense – or unidentified related form
** †Stemmatoceras arcicostum
** †Stemmatoceras palliseri – or unidentified related form
* †Stygiochelys – type locality for genus
** †Stygiochelys estesi – type locality for species
* †Sumitomoceras
* †Suuwassea – type locality for genus
** †Suuwassea emilieae – type locality for species
* †Symmetrodontoides
** †Symmetrodontoides canadensis
* †Synechodus
** †Synechodus andersoni – type locality for species
** †Synechodus striatus – type locality for species

## T

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Tancredia
** †Tancredia inornata – or unidentified comparable form
* †Tarrantoceras
** †Tarrantoceras cuspidum
* †Tatankacephalus – type locality for genus
** †Tatankacephalus cooneyorum – type locality for species
* †Taxodiaceaepollenites
** †Taxodiaceaepollenites hiatus
* Life restoration of the Early Cretaceous Iguanodon relative Tenontosaurus †Tenontosaurus – type locality for genus
** †Tenontosaurus tilletti – type locality for species
* †Terminonaris – type locality for genus
** †Terminonaris browni – type locality for species
** †Terminonaris robusta – type locality for species
* †Thalassomedon – type locality for genus
** †Thalassomedon hanningtoni – type locality for species
* †Thescelosaurus
** †Thescelosaurus garbanii – type locality for species
** †Thescelosaurus neglectus
* †Thescelus
** †Thescelus insiliens
* †Thlaeodon – tentative report
* †Todisporites
** †Todisporites dubius – or unidentified comparable form
* †Toxolophosaurus – type locality for genus
** †Toxolophosaurus cloudi – type locality for species
* †Trachodon – type locality for genus
** †Trachodon altidens
** †Trachodon marginatus
** †Trachodon mirabilis – type locality for species
* †Trachytriton
** †Trachytriton – type locality for species – informal
* Mounted fossilized skeleton of the Late Cretaceous horned dinosaur Triceratops †Triceratops
** †Triceratops horridus
** †Triceratops maximus – type locality for species
** †Triceratops prorsus
* †Trigonia
** †Trigonia conradi – or unidentified comparable form
** †Trigonia montanaensis
** †Trigonia trafalgarensis – or unidentified comparable form
* †Trigonocallista
** †Trigonocallista orbiculata
* Trionyx
* †Triprismatoolithus – type locality for genus
** †Triprismatoolithus stephensi – type locality for species
* †Trochicola
** †Trochicola scollardiana
* †Trochodendroides
* Illustration of fossilized teeth of the Late Cretaceous Troodon †Troodon – type locality for genus
** †Troodon formosus – type locality for species
* †Tubercuoolithus – type locality for genus
** †Tubercuoolithus tetonensis – type locality for species
* †Tubulifloridites
** †Tubulifloridites aedicula
* †Tullochelys
** †Tullochelys montana
* †Turgidodon
** †Turgidodon praesagus
** †Turgidodon rhaister
** †Turgidodon russelli
* Turritella
* †Tylosaurus
** †Tylosaurus proriger
* Fossilized skeleton of the Late Cretaceous tyrannosaur Tyrannosaurus †Tyrannosaurus – type locality for genus
** †Tyrannosaurus rex – type locality for species

## U

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Ugrosaurus – type locality for genus
** †Ugrosaurus olsoni – type locality for species
* Unio
* †Unionites
** †Unionites fassaensis

## V

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Valenopsalis
** †Valenopsalis joyneri
* Valvata – tentative report
** †Valvata montanensis
* †Varalphadon
** †Varalphadon wahweapensis
* †Veniella
* Vitis – report made of unidentified related form or using admittedly obsolete nomenclature
** †Vitis stantoni
* Viviparus
** †Viviparus couesii
* Life restorations of the Late Cretaceous marine bivalve Volviceramus †Volviceramus
** †Volviceramus exogyroides
** †Volviceramus involutus

## W

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Weediaphyllum – type locality for genus
** †Weediaphyllum parkensis – type locality for species
* †Weltrichia
* †Wodehousia
** †Wodehousia spinata
* †Woodwardia – report made of unidentified related form or using admittedly obsolete nomenclature
** †Woodwardia crenata

## X

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Xenocephalites – tentative report
* A view of the fossil shell of Xenophora infundibulum Xenophora

## Y

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Yezoites
** †Yezoites delicatulus

## Z

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* Fossil of the Early Triassic-Eocene cycad-like frond Zamites †Zamites
** †Zamites arcticus
* †Zapsalis – or unidentified comparable form
* †Zephyrosaurus – type locality for genus
** †Zephyrosaurus schaffi – type locality for species
* †Zlivisporis
** †Zlivisporis cenomanianus
* †Zygastrocarcinus
** †Zygastrocarcinus waagei