List of the Paleozoic life of Utah

This list of the Paleozoic life of Utah contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of Utah and are between 538.8 and 252.17 million years of age.

A

†Acanthopecten
- †Acanthopecten carboniferus
- †Acanthopecten coloradoensis
†Achlysopsis
- †Achlysopsis liokata – or unidentified comparable form
- †Achlysopsis punctatum
†Acidiphorus
- †Acidiphorus brevis – or unidentified comparable form
- †Acidiphorus brevus
- †Acidiphorus brighti
- †Acidiphorus pseudobathurus
- †Acidiphorus unicorna – type locality for species
- †Acidiphorus wahwahensis
- †Acidiphorus williamsi – type locality for species
†Acinocricus
- †Acinocricus stichus
†Acodus
- †Acodus similaris
†Acontiodus
- †Acontiodus coniformis
†Acrothele
- †Acrothele subsidua
†Acrotreta
†Adiantites
- †Adiantites tenuifolius
†Aesiocrinus
- †Aesiocrinus secundus – type locality for species
Assemblage of fossils of the Cambrian trilobite Agnostus
†Agnostus
- †Agnostus neglectus
†Allorisma
†Allorynchus
†Alokistocare
- †Alokistocare carnatum
- †Alokistocare harrisi
- †Alokistocare idahoense
- †Alokistocare normale
- †Alokistocare subcoronatum
†Alokistocarella
- †Alokistocarella brighamensis
†Altiocculus
- †Altiocculus concavus
- †Altiocculus drumensis
†Amblycranium
- †Amblycranium cornutum
- †Amblycranium linearus – type locality for species
- †Amblycranium variabile
†Amecephalus
- †Amecephalus laticudum
†Ameura – tentative report
†Ammagnostus
- †Ammagnostus beltensis
†Amphiscapha
†Amplexizaphrentis
- †Amplexizaphrentis paucicinctus
- †Amplexizaphrentis spinulosus
- †Amplexizaphrentis subcrassus
†Amplexocarina
†Amplexus^{[clarification needed]}
†Anabarochilna
- †Anabarochilna australis – or unidentified comparable form
†Ananias
- †Ananias nevadensis – or unidentified related form
†Ancillotoechia
- †Ancillotoechia perryi – type locality for species
†Anemonaria
- †Anemonaria delicatula
†Angulotreta
†Angyomphalus
- †Angyomphalus regularis
†Anidanthus
- †Anidanthus echaris
†Anisopyge
†Anisotrypa
†Annularia
- †Annularia stellata
†Annulispongia – type locality for genus
- †Annulispongia interrupta – type locality for species
Restorative model of the Cambrian arthropod Anomalocaris
†Anomalocaris
- †Anomalocaris nathorsti
†Anomalorthis
- †Anomalorthis lambda
- †Anomalorthis oklahomensis
- †Anomalorthis utahensis
†Anomphalus
- †Anomphalus rotulus
†Anthaspidella
†Anthracospirifer
- †Anthracospirifer increbescens
- †Anthracospirifer leidyi
- †Anthracospirifer occiduus
†Antiquatonia
- †Antiquatonia portlockianus
- †Antiquatonia sulcatus – or unidentified comparable form
†Apachella
†Apatognathus
†Aphelaspis
- †Aphelaspis haguei
†Aphelotoxon
- †Aphelotoxon acuminata
†Apheoorthis
- †Apheoorthis melita – or unidentified comparable form
†Apheorthis
- †Apheorthis meeki – or unidentified comparable form
†Archaeocalamites
- †Archaeocalamites scrobiculatus
†Archaeocothurnus – tentative report
- †Archaeocothurnus bifida – type locality for species
†Archaeoscyphia
- †Archaeoscyphia rossi
†Archeocalamites
- †Archeocalamites radiatus
†Archeoschyphia
Fossils of the Carboniferous-Permian bryozoan Archimedes
†Archimedes
- †Archimedes macfarlani
- †Archimedes owenanus
†Arcuolimbus
†Arenicolites
†Arroyocrinus
- †Arroyocrinus stokesi – type locality for species
†Arthrophycus – tentative report
†Artisia
†Asaphelina
†Asaphellus – tentative report
Fossil of the Cambrian trilobite Asaphiscus
†Asaphiscus
- †Asaphiscus wheeleri
†Ascopora
- †Ascopora macellata
†Astartella
- †Astartella subquadrata
†Asterophyllites
- †Asterophyllites charaeformis
- †Asterophyllites equisetiformis
- †Asterophyllites longifolius
†Athabaskia
- †Athabaskia bithus
- †Athabaskia wasatchensis
†Athyridacid
†Athyris
- †Athyris lamellosa
Fossilized shell of the Late Ordovician-Carboniferous brachiopod Atrypa
†Atrypa
- †Atrypa hedei
- †Atrypa parva – or unidentified comparable form
†Atrypid
†Aulacoparia – tentative report
- †Aulacoparia quadrata
- †Aulacoparia venta
†Aulacotheca
- †Aulacotheca campbellii
- †Aulacotheca hemingwayi
†Aulopora – tentative report
†Aviculopecten
- †Aviculopecten girtyi
- †Aviculopecten kaibabensis – or unidentified comparable form
†Aviculopinna
- †Aviculopinna peracuta – tentative report
Fossil of the Cambrian velvet worm relative Aysheaia
†Aysheaia

B

†Babylonites
- †Babylonites conoideus
†Bakevellia
†Baltagnostus
- †Baltagnostus eurypyx
†Barrandia – tentative report
†Bathymyonia
- †Bathymyonia nevadensis
†Bathyurellus
- †Bathyurellus feitleri
- †Bathyurellus pogonipensis
- †Bathyurellus pogonopensis
- †Bathyurellus teretus – type locality for species
†Bathyuriscus
- †Bathyuriscus brighamensis
- †Bathyuriscus elegans
- †Bathyuriscus fimbriatus
- †Bathyuriscus wasatchensis
†Bayfieldia
†Bearriverops
- †Bearriverops alsacharovi – type locality for species
- †Bearriverops borderinnensis – type locality for species
- †Bearriverops deltaensis – type locality for species
- †Bearriverops ibexensis – type locality for species
- †Bearriverops loganensis
†Beckwithia
- †Beckwithia typa
†Belemnospongia
- †Belemnospongia neofascicularis – type locality for species
†Bellazona
- †Bellazona bella
- †Bellazona polita – type locality for species
†Bellefontia
- †Bellefontia acuminiferentis
- †Bellefontia chamberlaini
- †Bellefontia ibexensis
†Benthamaspis
- †Benthamaspis diminutiva
- †Benthamaspis gibberula – type locality for species
- †Benthamaspis obrepta
†Beyrichoceras
†Bighornia
†Billingsella
†Biscoia
†Blastoidocrinus
- †Blastoidocrinus carchariaedens – or unidentified comparable form
†Blountia
†Bolaspidella
- †Bolaspidella contracta
- †Bolaspidella housensis
- †Bolaspidella type locality for species – informal
- †Bolaspidella wellsvillensis
†Bolbocephalus
†Bollandoceras
- †Bollandoceras occidentale – type locality for species
†Bonneterrina
†Bourbonnella
- †Bourbonnella jocelynae – type locality for species
†Bowmania
†Brachyaspidion
- †Brachyaspidion microps
- †Brachyaspidion sulcatum
†Brachyprion
- †Brachyprion geniculata
†Brachythyris
Life restoration of the mysterious Cambrian animal Branchiocaris
†Branchiocaris
- †Branchiocaris pretiosa
†Brassicicephalus
†Breckwithia
- †Breckwithia typa
†Brodioptera
- †Brodioptera stricklani – type locality for species
†Bromella
†Brooksella
†Bucania
†Bythicheilus
- †Bythicheilus typicum

C

†Cactocrinus
- †Cactocrinus arnoldi
Fossilized stems from the Carboniferous-Permian horsetail relative Calamites
†Calamites
- †Calamites cistii – or unidentified comparable form
- †Calamites cistiiformis
- †Calamites gigas
- †Calamites hesperius
- †Calamites infractus
- †Calamites suckowii
†Calamostachys – tentative report
†Calathium
- †Calathium yersini – type locality for species
†Callipteris – tentative report
†Callocladia
- †Callocladia jensensis
†Calycocoelia
†Calygirtyoceras
- †Calygirtyoceras arcticum
- †Calygirtyoceras confusionense – type locality for species
†Camarotoechia
†Cambromedusa – type locality for genus
- †Cambromedusa furcula – type locality for species
†Camerella
†Campbelloceras – tentative report
Life restoration of the Cambrian arthropod Canadaspis (left)
†Canadaspis
- †Canadaspis perfecta – or unidentified comparable form
†Canadia
†Canadiphyllum
†Cancrinella
- †Cancrinella phosphatica – or unidentified comparable form
†Caninaphyllum
- †Caninaphyllum incrussatum
†Caninia
- †Caninia torquia
†Caninophyllum
†Canthylotreta
- †Canthylotreta marjumensis
†Cardiomorpha
†Cardiopteris
- †Cardiopteris hirta – or unidentified comparable form
†Carolinites
- †Carolinites ekphymosus
- †Carolinites genacinaca – type locality for species
- †Carolinites killarnyensis
- †Carolinites killaryensis
†Castericystis
- †Castericystis sprinklei – type locality for species
- †Castericystis vali – type locality for species
†Catoraphiceras
- †Catoraphiceras colon
†Caulpsis
- †Caulpsis punctata
†Cavusgnathus
- †Cavusgnathus regularis
- †Cavusgnathus unicornis
Fossil of the Cambrian trilobite Cedaria
†Cedaria
- †Cedaria minor
†Cedarina – tentative report
†Cenorhynchia
- †Cenorhynchia type locality for species A – informal
†Cernuolimbus
- †Cernuolimbus granulosus
†Chaenomya
†Chaetetes
- †Chaetetes milleporaceous
†Chancelloria
- †Chancelloria eros
- †Chancelloria pentacta – type locality for species
†Chancia)
- †Chancia ebdome – or unidentified comparable form
†Chanciaopsis – type locality for genus
- †Chanciaopsis heteromorphos – type locality for species
†Chanciopsis
- †Chanciopsis heteromorphos
†Cheilocephalus
†Chilotrypa
Life restoration of the Cambrian sponge Choia
†Choia
- †Choia carteri
- †Choia hindei
- †Choia ridleyi
- †Choia utahensis
†Chondrites
†Chonetes
†Chonetina
- †Chonetina flemingi
†Choristites
- †Choristites fritschi – or unidentified comparable form
- †Choristites pavlovi – or unidentified comparable form
Fossil of the Carboniferous tabulate coral Cladochonus
†Cladochonus
†Clathrospira – tentative report
†Clavagnostus
- †Clavagnostus repandus
†Cleiothyridina
- †Cleiothyridina type locality for species A – informal
- †Cleiothyridina type locality for species B – informal
†Clelandia
- †Clelandia utahensis
†Cliothyridina
- †Cliothyridina orbicularis
†Clonograptus
†Coelogasteroceras
†Coenites
†Colinispongia
- †Colinispongia regularis
Fossilized shell of the Late Devonian-Permian brachiopod Composita
†Composita
- †Composita argentea
- †Composita mira
- †Composita ovata
- †Composita parasulcata
- †Composita plana
- †Composita subtilita
- †Composita trilobata
- †Composita trinuclea
†Condrathyris
- †Condrathyris perplexa
†Conotreta
- †Conotreta millardensis
†Coosella
†Coosina
†Cordaianthus
- †Cordaianthus pseudofluitans
†Cordaicarpus
- †Cordaicarpus binutus – type locality for species
- †Cordaicarpus cordatus
- †Cordaicarpus elongatus
- †Cordaicarpus globosus – type locality for species
- †Cordaicarpus jayshulerii – type locality for species
- †Cordaicarpus manningcanensis – type locality for species
Fossilized foliage of the Carboniferous-Permian conifer relative Cordaites
†Cordaites
- †Cordaites angulosostriatus
- †Cordaites principalis
- †Cordaites Sp. A – informal
- †Cordaites Sp. B – informal
†Cornucarpus
- †Cornucarpus longicaudatus – type locality for species
†Corynepteris
- †Corynepteris angustissima
†Costellarina
†Cotalagnostus
Crania
- †Crania rowleyi
†Cravenoceras
†Crepicephalus
†Crossopteris – type locality for genus
- †Crossopteris mcknightii – type locality for species
- †Crossopteris undulata – type locality for species
- †Crossopteris utahensis – type locality for species
†Crurithyris
- †Crurithyris arcuatus – or unidentified comparable form
- †Crurithyris expansa – tentative report
†Cruziana
†Ctenalosia
- †Ctenalosia fixata
†Ctenocystis
- †Ctenocystis utahensis
†Ctenospondylus
- †Ctenospondylus casei – or unidentified related form
†Cyathaxonia
†Cyathocarpus
- †Cyathocarpus arborescens
- †Cyathocarpus cyatheus
†Cybeloides
†Cybelopsis
- †Cybelopsis speciosa
Fossilized foliage from the Carboniferous seed fern Cyclopteris
†Cyclopteris
- †Cyclopteris dilatata
†Cymatospira
- †Cymatospira montfortianus
†Cymbiocrinus
- †Cymbiocrinus anatonus – type locality for species
- †Cymbiocrinus cuneatus – type locality for species
†Cyperites
- †Cyperites bicarinatus
†Cyrtia
†Cyrtina
†Cyrtorostra
†Cystodictya
- †Cystodictya astrepta

D

†Dalmanellida
†Deiracephalus
†Delaria
- †Delaria sevilloidia
†Delocrinus
- †Delocrinus subhemisphericus
†Deltina – type locality for genus
- †Deltina limba – type locality for species
Dentalium
†Derbyia
- †Derbyia bennetti
- †Derbyia crassa
- †Derbyia sulca
- †Derbyia wabashensis
†Desmoinesia
- †Desmoinesia muricatina
†Diacanthaspis
- †Diacanthaspis trispineus – type locality for species
Life restoration of the Permian reptile relative Diadectes
†Diadectes
†Diagoniella
- †Diagoniella cyathiformis
- †Diagoniella hindei
- †Diagoniella magna – type locality for species
- †Diagoniella robisoni – type locality for species
†Diaphragmus
- †Diaphragmus cestriensis
†Dicanthopyge
- †Dicanthopyge convergens
†Dicranocaris
- †Dicranocaris guntherorum
†Dictyoclostus
- †Dictyoclostus burlingtonensis
- †Dictyoclostus inflatus
†Dictyonema
- †Dictyonema flabelliforme – or unidentified comparable form
Fossil of the Middle Ordovician graptolite Didymograptus
†Didymograptus
- †Didymograptus artus
- †Didymograptus bifidus
- †Didymograptus nitidus – or unidentified comparable form
†Dielasma
- †Dielasma formosum
- †Dielasma phosphoriense
- †Dielasma spatulatum
†Dimegelasma
†Dimeropygiella
- †Dimeropygiella blanda
- †Dimeropygiella caudanodosa – type locality for species
- †Dimeropygiella fillmorensis
- †Dimeropygiella mccormicki
- †Dimeropygiella ovata
†Dimorphoceras
- †Dimorphoceras rileyi – type locality for species
- †Dimorphoceras worki – type locality for species
†Dioxycaris
- †Dioxycaris argenta
†Diparalasma
†Diparelasma
- †Diparelasma pogonipensis – or unidentified comparable form
- †Diparelasma rowelli
- †Diparelasma transversum – or unidentified comparable form
†Diphyphyllum
†Diplagnostus
- †Diplagnostus planicauda
†Diplorrhina
- †Diplorrhina depressa
†Diplothmema
- †Diplothmema arnoldi
- †Diplothmema obtusiloba
- †Diplothmema trifoliolata
†Diplotrypa – tentative report
†Ditomopyge
†Dolerorthis – tentative report
- †Dolerorthis flabellites
†Donaldina
†Dorypyge
- †Dorypyge swasii
- †Dorypyge wellsvillensis
†Drepanodus
- †Drepanodus homocurvatus
†Dresbachia
- †Dresbachia amata
†Duartea
- †Duartea bruntoni
†Dunbarinella – tentative report
†Dunderbergia
- †Dunderbergia anyta
- †Dunderbergia bigranulosa – tentative report
†Dyoros
- †Dyoros type locality for species A – informal
†Dysoristus
†Dytremacephalus
†Dzhaprakoceras

E

†Echinalosia
- †Echinalosia type locality for species A – informal
†Echinaria^{[clarification needed]}
- †Echinaria semipunctata – or unidentified related form
†Echinauris – or unidentified comparable form
- †Echinauris subhorrida
†Echinoconchus
- †Echinoconchus elegans
- †Echinoconchus semipunctatus
†Echinocrinus
†Ectenonotus
- †Ectenonotus progenitor
- †Ectenonotus whittingtoni
Life restoration of the Permian lobe-finned fish Ectosteorhachis
†Ectosteorhachis – or unidentified related form
- †Ectosteorhachis nitidus
†Edmondia
†Ehmaniella
- †Ehmaniella quadrans – tentative report
†Ekvasophyllum
- †Ekvasophyllum inclinatum
†Elburgia
- †Elburgia granulosa
- †Elburgia intermedia
†Eldonia
- †Eldonia ludwigi
†Eleutherocentrus
- †Eleutherocentrus petersoni
†Elrathella
Fossils at different stages of development of the Cambrian trilobite Elrathia
†Elrathia
- †Elrathia kingi
†Elrathiella
- †Elrathiella dugwayensa – type locality for species
†Elrathina
- †Elrathina spencei
†Elvinia
†Emeraldella
†Endelocrinus
- †Endelocrinus matheri
†Endoceras
†Entogonites
- †Entogonites acus
- †Entogonites borealis
- †Entogonites burbankensis – type locality for species
†Eoastarte
- †Eoastarte subcircularis
†Eofletcheria
†Eoorthis
†Eriaster – type locality for genus
- †Eriaster ibexensis – type locality for species
†Eridopora
†Eridotrypa
- †Eridotrypa hindsi
- †Eridotrypa subtilis
†Erixanium
- †Erixanium carinatum
Life restoration of the Carboniferous-Permian amphibian Eryops
†Eryops
†Euconospira
†Eukrinaster – type locality for genus
- †Eukrinaster ibexensis – type locality for species
†Eukteanochiton – type locality for genus
- †Eukteanochiton milleri – type locality for species
†Euloma – report made of unidentified related form or using admittedly obsolete nomenclature
- †Euloma cordilleri
†Eumetria
- †Eumetria acuticosta
- †Eumetria costata
†Euphemites
- †Euphemites carbonarius
†Euphemitopsis
- †Euphemitopsis subpapillosa – type locality for species
†Euptychaspis
†Eurekia
†Eurytreta
- †Eurytreta bisecta – or unidentified comparable form
- †Eurytreta fillmorensis – type locality for species

F

†Faberophyllum
†Falcatamacaris – type locality for genus
- †Falcatamacaris bellua – type locality for species
†Fenestella
- †Fenestella acarinata
- †Fenestella crockfordae
- †Fenestella dissepinodaria
- †Fenestella hamithensis
- †Fenestella incipiens
- †Fenestella parallela
- †Fenestella rarinodosa
- †Fenestella regalis
- †Fenestella serratula
- †Fenestella tooelensis
- †Fenestella trifurcata
- †Fenestella utahensis
†Fenestralia
- †Fenestralia sanctiludovici
†Fenestrellina
†Fistulipora
†Forteyops
- †Forteyops sexapugia – type locality for species
†Fusulinella

G

†Gattendorfia
†Genalaticurus
- †Genalaticurus genalatus
Fossil of the Cambrian trilobite Genevievella
†Genevievella
- †Genevievella granulatus
†Girtyella – tentative report
†Girtyoceras
- †Girtyoceras gordoni – type locality for species
- †Girtyoceras hamiltonense
- †Girtyoceras primum – type locality for species
†Girtypecten
†Girtyspira
†Girvanella
†Glabrocingulum
- †Glabrocingulum coronatum
- †Glabrocingulum granulosum – type locality for species
- †Glabrocingulum mephitifontis – type locality for species
†Glaphyrites
- †Glaphyrites nevadensis
†Globocrinus
- †Globocrinus bulbus – type locality for species
†Glochinomorpha – type locality for genus
- †Glochinomorpha stifeli – type locality for species
†Glosopleura
†Glossopleura
- †Glossopleura boccar
- †Glossopleura gigantea
- †Glossopleura producta
- †Glossopleura prona
- †Glossopleura punctatum
†Glyphaspis
- †Glyphaspis concavus – type locality for species
†Glyptospira
†Gnathodus
- †Gnathodus texanus
†Gnetopsis
- †Gnetopsis anglica
Fossil of the Cambrian echinoderm Gogia
†Gogia
- †Gogia granulosa
- †Gogia guntheri
- †Gogia kitchnerensis
- †Gogia spiralis
†Goleocrinus
- †Goleocrinus vadosus – type locality for species
- †Goleocrinus vedosus
†Goniasma
†Goniatites
- †Goniatites americanus
- †Goniatites deceptus – type locality for species
- †Goniatites eganensis
- †Goniatites sowerbyi
†Goniophrys
- †Goniophrys prima
†Goniotelena
- †Goniotelena ensifer
†Goniotelina
- †Goniotelina ensifer
- †Goniotelina plicolabeonus – type locality for species
†Goniotelus – tentative report
- †Goniotelus ludificatus
†Gonitelina
†Gothodus
- †Gothodus communis
†Grammatodon
- †Grammatodon politus
†Grandaurispina – or unidentified comparable form
- †Grandaurispina type locality for species A – informal
†Gruntia – tentative report
†Guizhoupecten – tentative report
- †Guizhoupecten tubicostata – or unidentified comparable form
†Gujocardita
- †Gujocardita parviradiatus – type locality for species
†Gunterichthys – type locality for genus
- †Gunterichthys lehiensis – type locality for species

H

†Haimacystis
- †Haimacystis rozhnovi
†Hammatocyclus
- †Hammatocyclus brazerensis – type locality for species
†Hamptonia
- †Hamptonia bowerbanki
- †Hamptonia parva – type locality for species
†Haplistion
- †Haplistion sphaericum
Life restoration of the Cambrian brachiopod relative Haplophrentis
†Haplophrentis
- †Haplophrentis carinatus
- †Haplophrentis reesei
†Hardyoides
†Hazelia
- †Hazelia palmata
†Heckethornia
- †Heckethornia alticapitis – type locality for species
- †Heckethornia ballionae – type locality for species
- †Heckethornia bowiei – type locality for species
- †Heckethornia hyndeae
- †Heckethornia morrisseyi – type locality for species
- †Heckethornia numani
- †Heckethornia smithi – type locality for species
†Heintzella
- †Heintzella whitneyi
Life restoration of the Permian Chimaera relative Helicoprion
†Helicoprion
†Helicospira
†Hematites
- †Hematites barbarae – type locality for species
- †Hematites burbankensis – type locality for species
†Hemiptychina
- †Hemiptychina quadricostata
†Hemirhodon
- †Hemirhodon amplipyge
†Hemitrypa
- †Hemitrypa reticulata
†Hesperonomia
- †Hesperonomia dinorthoides
- †Hesperonomia fontinalis
- †Hesperonomia frontinalis
†Hesperonomiella
- †Hesperonomiella minor
†Heteralosia
†Heteropecten
- †Heteropecten vanvleeti – or unidentified comparable form
†Hillyardina
- †Hillyardina marginauctum
- †Hillyardina semicylindrica – or unidentified comparable form
†Hindia^{[clarification needed]}
- †Hindia sphaeroidalus
†Hintzecurus
- †Hintzecurus paragenalatus
†Hintzeia
- †Hintzeia aemula
- †Hintzeia celsaora
- †Hintzeia firmimarginis
†Hintzespongia – type locality for genus
- †Hintzespongia bilamina – type locality for species
†Holcospermum
†Homagnostus
†Homalophyllites
†Hormotoma – tentative report
†Housia
†Howellella
†Hudsonospongia – tentative report
†Huronia
- †Huronia vertebralis
†Hustedia
- †Hustedia elongata
- †Hustedia mormoni – type locality for species
†Hyattidina – tentative report
†Hyolithellus

Fossilized shells of the Cambrian-Permian brachiopod relative *Hyolitha*

†Hyolithes

- †Hyolithes comptus
†Hypagnostus
- †Hypagnostus parvifrons
Hyperammina
†Hyperbolochilus
†Hypselocrinus
- †Hypselocrinus cavus – type locality for species
- †Hypselocrinus defendus – type locality for species
- †Hypselocrinus secundus
- †Hypselocrinus superus – type locality for species
†Hystriculina
- †Hystriculina fragilis
- †Hystriculina wabashensis
†Hystricurus
- †Hystricurus contractus
- †Hystricurus oculilunatus
- †Hystricurus robusta

I

†Ianthinopsis
†Ibexella
- †Ibexella multidiaphragmata
†Ibexicurus
- †Ibexicurus parsonsi – type locality for species
†Iddingsia
†Idiognathodus
†Idiomesus
†Illaenurus
Fossil of the Middle Ordovician trilobite Illaenus
†Illaenus
- †Illaenus utahensis
†Inflatia
- †Inflatia bilobata
†Iphidella
†Irvingella^{[clarification needed]}
- †Irvingella flohri – tentative report
- †Irvingella major
†Ischyrotoma
- †Ischyrotoma juabensis
- †Ischyrotoma wahwahensis
†Isorthis
†Isoteloides
- †Isoteloides flexus
- †Isoteloides polaris
†Isoxyes

J

†Jeffersonia
†Jenkinsonia
- †Jenkinsonia varga
†Juresania
- †Juresania nebraskensis

K

†Kainella
†Kanoshia
- †Kanoshia depressus – type locality for species
- †Kanoshia kanoshensis
- †Kanoshia reticulata
†Kanoshopora
- †Kanoshopora droserae
†Kawina
- †Kawina webbi
- †Kawina wilsoni
†Kazakhoceras
- †Kazakhoceras bylundi – type locality for species
†Kindbladia
- †Kindbladia affinis
†Kingstonia
†Kirkella^{[clarification needed]}
- †Kirkella fillmorensis
†Kiwetinokia
- †Kiwetinokia utahensis
†Kochina
- †Kochina vestita
†Kochiproductus
†Komia^{[clarification needed]}
†Komiella
- †Komiella ostiolata
Fossil of the Cambrian trilobite Kootenia
†Kootenia
- †Kootenia acicularis
- †Kootenia mendosa
- †Kootenia quadriceps
- †Kootenia spencei
†Kootina
- †Kootina pectenoides
†Kormagnostella
- †Kormagnostella advena
- †Kormagnostella insolita
†Kormagnostus
†Kozlowskia
- †Kozlowskia capaci – or unidentified related form
†Kutorginella
- †Kutorginella lasallensis
†Kuvelousia
- †Kuvelousia leptosa

L

†Lachnostoma
- †Lachnostoma latucelsum – type locality for species
†Lagenospermum
- †Lagenospermum discissium – type locality for species
†Lamellispira
†Lavadamia
- †Lavadamia joplinae – type locality for species
†Leanchoila
- †Leanchoila protogonia
- †Leanchoila superlata
Life restoration in multiple views of the Cambrian arthropod Leanchoilia
†Leanchoilia
- †Leanchoilia hanceyi
- †Leanchoilia superlata
†Lecanospira
†Leiorhynchoidea
†Leiorhynchus
†Leiostegium
- †Leiostegium formosa
- †Leiostegium manitouense – or unidentified comparable form
- †Leiostegium manitouensis
†Lejopyge
- †Lejopyge calva
†Leperditia
- †Leperditia bivia
†Lepidocarpon
- †Lepidocarpon linearifolium
Life restoration of the Carboniferous tree-sized club moss relative Lepidodendron
†Lepidodendron
- †Lepidodendron aculeatum
- †Lepidodendron obovatum
- †Lepidodendron volkmannianum
†Lepidophylloides
†Lepidophyllum
- †Lepidophyllum longifolium
†Lepidostrobophyllum
- †Lepidostrobophyllum majus
†Lepidostrobus
- †Lepidostrobus obovatus
- †Lepidostrobus variabilis
†Leptaena
†Leptalosia
- †Leptalosia scintilla – or unidentified comparable form
†Leptanena
†Leptomitella
- †Leptomitella metta – type locality for species
†Leptomitus
†Lesuerilla – tentative report
†Licnocephala
- †Licnocephala bicornuta – tentative report
- †Licnocephala cavigladius
Lima^{[clarification needed]}
†Limapecten
Limatula
†Limipecten
†Linevitus
- †Linevitus billingsi
Lingula
- †Lingula carbonaria
Illustration of a fossilized shell of the Cambrian-Late Ordovician brachiopod Lingulella
†Lingulella
- †Lingulella incurvata
- †Lingulella pogonipensis – or unidentified comparable form
†Linipalus
- †Linipalus magnispinus
†Linnarssonella
†Linnarssonia
- †Linnarssonia bellatula
- †Linnarssonia ophirensis
†Linoproductus
- †Linoproductus meniscus
- †Linoproductus ovatus
- †Linoproductus planiventralis – tentative report
- †Linoproductus prattenians
- †Linoproductus prattenianus
†Lissocoelia
- †Lissocoelia cylindrica
†Lithostrontionella
†Lithostrotionella
- †Lithostrotionella americana – or unidentified comparable form
†Llanoaspis
†Lobatospongia – type locality for genus
- †Lobatospongia nodensis – type locality for species
†Lochriea
- †Lochriea commutata
†Lonchocephalus
†Lophophyllidium
- †Lophophyllidium profundum
†Loxonema
†Loxoplocus
†Lunulazona
- †Lunulazona costata
- †Lunulazona nodomarginata
†Lyracystis
- †Lyracystis reesei

M

†Macluritella
†Maclurites
†Macronotella
†Madaraspis
- †Madaraspis magnifica
Restoration of the mysterious Cambrian life-form Margaretia
†Margaretia
- †Margaretia dorus
†Marginifera
†Marginovatia
- †Marginovatia catinulus
†Mariopteris
- †Mariopteris muricata
†Marjumicystis
- †Marjumicystis mettae – type locality for species
†Marpolia
†Matherella
†Matthevia
- †Matthevia variabilis
- †Matthevia wahwahensis – type locality for species
†Meekopora
†Meekospira
†Menomonia
- †Menomonia semele
†Menoparia
- †Menoparia genalunata
†Metabowmania
- †Metabowmania braggi – type locality for species
- †Metabowmania morgani
Fossilized shell of the Carboniferous-Permian nautiloid cephalopod Metacoceras
†Metacoceras
†Metadimorphoceras
- †Metadimorphoceras mangeri – type locality for species
- †Metadimorphoceras richardsi
†Meteoaspis – tentative report
†Meteoraspis
†Michelinia
†Microcardinalia
†Micromitra
- †Micromitra pannula
†Millardicurus
- †Millardicurus housensis – type locality for species
- †Millardicurus millardensis
- †Millardicurus paramillardensis – type locality for species
†Modiolopsis
Modiolus – report made of unidentified related form or using admittedly obsolete nomenclature
†Modocia
- †Modocia brevispina
- †Modocia laevinucha
- †Modocia typicalis
- †Modocia weeksensis – type locality for species
†Mollisonia
- †Mollisonia symmetrica
†Morania
- †Morania fragmenta
†Mourlonia
- †Mourlonia venusta – type locality for species
†Myalina

N

†Nanorthis
- †Nanorthis hamburgensis
- †Nanorthis multicostata
Restoration of the Cambrian-Silurian arthropod Naraoia
†Naraoia
- †Naraoia compacta
†Narynella
- †Narynella sulcata
†Naticopis
- †Naticopis altonensis – tentative report
†Naticopsis
†Natiria
†Neochonetes
- †Neochonetes granulifer
†Neolenus
- †Neolenus inflatus – type locality for species
- †Neolenus intermedius – type locality for species
- †Neolenus superbus
†Neoprioniodus
- †Neoprioniodus scitulus
- †Neoprioniodus varians
Fossilized shell of the Carboniferous-Permian brachiopod Neospirifer
†Neospirifer
- †Neospirifer cameratus
- †Neospirifer kansasensis
- †Neospirifer triplicatus
†Neozaphrentis – tentative report
†Nephalicephalus – type locality for genus
- †Nephalicephalus beebei – type locality for species
†Nettapezoura
- †Nettapezoura basilika
†Neuralethopteris
- †Neuralethopteris pocahontas – or unidentified comparable form
Fronds of the Carboniferous seed fern Neuropteris
†Neuropteris
- †Neuropteris ampelina – type locality for species
- †Neuropteris gigantea
- †Neuropteris heterophylla
†Nieszkowskia – tentative report
†Niobe^{[clarification needed]} – tentative report
†Nisusia
†Norwoodia
- †Norwoodia bellaspina
†Nothorthis
†Nuculavus
†Nuculopsis
†Nuia
†Nunnacrinus
- †Nunnacrinus olsoni – type locality for species

O

†Obolus^{[clarification needed]}
- †Obolus ella
†Odontopteris
- †Odontopteris osmundaeformis – or unidentified comparable form
- †Odontopteris subcrenulata – or unidentified comparable form
†Odontospirifer
- †Odontospirifer type locality for species A – informal
†Oepikodus
- †Oepikodus quadratus
Fossil of the Cambrian trilobite Ogygopsis
†Ogygopsis
- †Ogygopsis typicalis
†Oistodus
- †Oistodus lanceolatus
- †Oistodus linguatus
- †Oistodus longiramis
- †Oistodus multicorrugatus – or unidentified related form
- †Oistodus parallelus
†Olenellus
- †Olenellus gilberti
†Olenoides
- †Olenoides expansus
- †Olenoides nevadensis
- †Olenoides serratus
- †Olenoides spencei
- †Olenoides tricephalus
Life restoration of the Carboniferous-Permian synapsid (mammal precursor) Ophiacodon
†Ophiacodon
- †Ophiacodon navajovicus
†Ophileta
†Opsioryctocephalus
- †Opsioryctocephalus opsis
†Orbiculoidea
- †Orbiculoidea capuliformis
- †Orbiculoidea missouriensis
- †Orbiculoidea utahensis – type locality for species
†Orbipora
- †Orbipora utahensis
†Orthambonites
- †Orthambonites eucharis – or unidentified comparable form
- †Orthambonites michaelis
- †Orthambonites subulata
†Orthis
- †Orthis subalata – or unidentified comparable form
- †Orthis subulata
- †Orthis swanensis
†Orthonema
- †Orthonema socorroense – or unidentified comparable form
†Orthotetes
- †Orthotetes kaskaskiensis
†Orthriochiton – type locality for genus
- †Orthriochiton utahensis – type locality for species
†Oryctocare
- †Oryctocare geikei
†Oryctocephalus
- †Oryctocephalus walcotti
†Ottenbyella
- †Ottenbyella ibexiana – type locality for species
Life restoration of the Cambrian priapulid worm relative Ottoia
†Ottoia
- †Ottoia prolifica
†Ovatia
- †Ovatia muralis
†Owenella
†Ozarkodina

P

†Pachycranium
- †Pachycranium faciclunis
Fossil of the Cambrian trilobite Pagetia
†Pagetia
- †Pagetia fossula – or unidentified comparable form
†Paladin
†Palaeacis
Palaeoaplysina
- †Palaeoaplysina laminaeformis
†Palaeobotryllus
†Palaeoneilo
- †Palaeoneilo parvaradiatus
†Palaeoscolex
- †Palaeoscolex ratcliffei
†Paleococrinus
†Palmerocrinus
- †Palmerocrinus profundus
†Paltodus
- †Paltodus jeffersonensis
†Parabellefontia
- †Parabellefontia concinna
†Parabolinoides
†Paracosmetocrinus
- †Paracosmetocrinus lundi – type locality for species
†Parahystricurus
- †Parahystricurus bispicatus
- †Parahystricurus fraudator
†Parajuresania
- †Parajuresania nebrascensis
†Parallelodon
†Parapilekia – tentative report
†Paraplethopeltis
- †Paraplethopeltis genacurvus
- †Paraplethopeltis genarectus
†Parkaspis
- †Parkaspis drumensis
†Peelerophon – tentative report
†Pelagiella
†Peniculauris
- †Peniculauris bassi
- †Peniculauris ivesi
†Penniretepora
†Pentameroides
†Pentamerus
†Pericyclus
†Permophorus
- †Permophorus albequus
- †Permophorus occidentalis
Assemblage of fossils of the Cambrian trilobite Itagnostus interstrictus, until recently known as Peronopsis interstricta
†Peronopsis
- †Peronopsis acadica
- †Peronopsis amplaxis
- †Peronopsis bonnerensis
- †Peronopsis brighamensis
- †Peronopsis fallax
- †Peronopsis interstricata
- †Peronopsis interstricta
- †Peronopsis montis
- †Peronopsis scutalis
- †Peronopsis segmenta
- †Peronopsis sermenta
†Perspicaris
- †Perspicaris ellipsopelta
†Petasmatherus
- †Petasmatherus type locality for species A – informal
†Petigurus
- †Petigurus inexpectatus
†Pharkidonotus
- †Pharkidonotus percarinatus
†Phillipsia
†Phosphannulus
†Phrenophoria
- †Phrenophoria type locality for species A – informal
†Phricodothyris
†Phyllograptus
†Pilekia
- †Pilekia trio – tentative report
Pinna – report made of unidentified related form or using admittedly obsolete nomenclature
†Plagioglypta
†Platycrinites
†Platycrinus
- †Platycrinus graphicus – or unidentified comparable form
Life restoration of the Carboniferous-Permian sail-backed amphibian Platyhystrix
†Platyhystrix – or unidentified comparable form
- †Platyhystrix rugosus
†Platyworthenia
†Plectelasma
- †Plectelasma type locality for species A – informal
- †Plectelasma type locality for species B – informal
†Plethospira
†Pleurosiphonella
- †Pleurosiphonella virginica
†Pliomerops
- †Pliomerops insolita
†Polidevcia
- †Polidevcia bellistriata
- †Polidevcia obesa
†Politicurus
- †Politicurus politus
†Polypora
- †Polypora cestriensis
- †Polypora debilis
- †Polypora micronodosa
- †Polypora stansburyensis
†Ponticulocarpus – type locality for genus
- †Ponticulocarpus robisoni – type locality for species
†Praedaraelites
- †Praedaraelites loeblichi
†Prehousia
- †Prehousia alata
- †Prehousia diverta
†Presbynileus
- †Presbynileus elongatus
- †Presbynileus ibexensis
- †Presbynileus utahensis
†Probolionia
†Prodentalium
- †Prodentalium canna
†Productella
†Productus – report made of unidentified related form or using admittedly obsolete nomenclature
†Proehmaniella
- †Proehmaniella basilica
†Prohedinia
- †Prohedinia spencei
†Prolecanites – tentative report
- †Prolecanites lyoni
†Prosaukia
†Protoblechnum
- †Protoblechnum bradyi – type locality for species
†Protopliomerella
- †Protopliomerella contracta
†Protopliomerops
- †Protopliomerops quattuor – type locality for species
†Protopresbynileus
- †Protopresbynileus willdeni
†Protoretepora
†Protospongia
- †Protospongia elongata
†Prototreta
†Protowentzelella
- †Protowentzelella cystosa
†Psalikilus
- †Psalikilus likum
- †Psalikilus paraspinosum
- †Psalikilus spinosum
- †Psalikilus typicum
†Psephosthenaspis
- †Psephosthenaspis glabrior
- †Psephosthenaspis microspinosa
- †Psephosthenaspis pseudobathyurus
†Pseudagnostus
†Pseudoarctolepis
- †Pseudoarctolepis sharpi
†Pseudoarctolepsis
- †Pseudoarctolepsis sharpi
†Pseudoclelandia
- †Pseudoclelandia fluxafissura – or unidentified related form
†Pseudocybele
- †Pseudocybele altinasuta
- †Pseudocybele lemurei
- †Pseudocybele nasuta – type locality for species
†Pseudodoriodotis
†Pseudohystricurus
†Pseudokainella – tentative report
- †Pseudokainella armatus
†Pseudomera
- †Pseudomera arachnopyge
- †Pseudomera barrandei – or unidentified comparable form
- †Pseudomera insolita
†Pseudomonotis
- †Pseudomonotis equistriata
†Pseudomphalotrochus
- †Pseudomphalotrochus incrustatus
†Pseudoolenoides
- †Pseudoolenoides acicaudus
- †Pseudoolenoides aspinosus
- †Pseudoolenoides dilectus
†Pseudopermophorus
- †Pseudopermophorus annettae
†Pseudoperonopsis
†Pseudorthoceras
†Pseudosaratogia – tentative report
†Pseudoschwagerina
†Pterocephalia
†Pteronites
†Ptychagnostus
- †Ptychagnostus aculeatus
- Fossil of the Cambrian trilobite Ptychagnostus atavus
  †Ptychagnostus atavus
- †Ptychagnostus cassis
- †Ptychagnostus germanus
- †Ptychagnostus intermedius
- †Ptychagnostus occultatus
- †Ptychagnostus punctuosus
- †Ptychagnostus richmondensis
- †Ptychagnostus seminula
†Ptychomphalus
†Ptychoparella
†Ptylopora
- †Ptylopora condrai
- †Ptylopora eliasi
†Ptyocephalus
- †Ptyocephalus accliva
- †Ptyocephalus declevita – type locality for species
- †Ptyocephalus declivita
- †Ptyocephalus versini
- †Ptyocephalus vigilans
†Pugnax^{[clarification needed]}
- †Pugnax utah – type locality for species
†Pugnoides
†Punctospirifer
- †Punctospirifer campestris
- †Punctospirifer kentuckensis
†Punka^{[clarification needed]}
- †Punka nitida – or unidentified comparable form

Q

†Quadratia
†Quadrisonia – tentative report
- †Quadrisonia lavadamensis
†Quadrochonetes
- †Quadrochonetes type locality for species A – informal

R

†Ramiporalia
†Raphistoma – tentative report
†Raphistomina
†Ratcliffespongia – type locality for genus
- †Ratcliffespongia perforata – type locality for species
- †Ratcliffespongia sheeleri
- †Ratcliffespongia wheeleri – type locality for species
†Rayonnoceras
- †Rayonnoceras solidiorme
Fossil of the Early Ordovician-Permian benthic alga Receptaculites
†Receptaculites
- †Receptaculites elongatus
- †Receptaculites mammilaris
- †Receptaculites mammillaris
†Rectifenestella
- †Rectifenestella tenax
†Regispongia
- †Regispongia contorta
†Remopleuridiella
- †Remopleuridiella angularis – type locality for species
- †Remopleuridiella caudalimbata
†Reticulatia
- †Reticulatia americana
†Retispira
- †Retispira cincta – type locality for species
- †Retispira textilis – or unidentified comparable form
†Rhabdomeson
- †Rhabdomeson artum
†Rhipidomella
- †Rhipidomella missouriensis
Shell of a Rhodea land snail
†Rhodea
- †Rhodea vespertina
†Rhombopora
- †Rhombopora tenuirama
†Rhynchopora
†Ribeiria
- †Ribeiria lucan
†Rigbyocarpus – type locality for genus
- †Rigbyocarpus ebracteatus – type locality for species
†Rodea
- †Rodea vespertina – or unidentified comparable form
†Rossaspis
- †Rossaspis superciliosa
†Rossicurus
- †Rossicurus lepidus
†Rugatia
- †Rugatia occidentalis
†Rugosochonetes
- †Rugosochonetes loganensis
Fossil of the arthropod burrow ichnogenus Rusophycus
†Rusophycus
†Rylstonia – tentative report

S

†Saffordotaxis
†Sanguinolites
- †Sanguinolites elongatus – type locality for species
†Saukia
Fossil of the Cambrian-Ordovician trilobite Saukiella
†Saukiella
†Scandodus
- †Scandodus furnishi
†Scaphellina – tentative report
†Scenella
- †Scenella radians
†Schizambon
- †Schizambon obtusus – type locality for species
†Schizodus
- †Schizodus bifidus
- †Schizodus subovatus – type locality for species
†Schizophoria
†Schmalenseeia
†Schuchertella
- †Schuchertella lens
†Schwagerina
†Scolicia
†Scolopodus
- †Scolopodus gracilis
- †Scolopodus pseudoquadratus
- †Scolopodus quadraplicatus
- †Scolopodus rex
†Seelyia
†Selenocoryphe – type locality for genus
- †Selenocoryphe platyura – type locality for species
Fossil of the Cambrian priapulid worm Selkirkia
†Selkirkia
- †Selkirkia columbia – or unidentified comparable form
- †Selkirkia spencei
- †Selkirkia willoughby
†Sentinelia – tentative report
- †Sentinelia draco – or unidentified comparable form
†Septimyalina
- †Septimyalina burmai – tentative report
†Septopora
- †Septopora ulrichi
†Shoshonorthis
- †Shoshonorthis michaelis
- †Shoshonorthis swanensis
†Shumardia
- †Shumardia exopthalmus
Restorative model of the Cambrian arthropod Sidneyia
†Sidneyia
†Sigillaria
- †Sigillaria brardii
†Sinuella – tentative report
†Siphonobolus – tentative report
†Spathognathus
- †Spathognathus cristulus
- †Spathognathus scitulus
†Spencella
- †Spencella utahensa – type locality for species
- †Spencella utahensis
Life restoration of the Carboniferous-Permian synapsid (mammal precursor) Sphenacodon
Sphenacodon
- †Sphenacodon ferocior – or unidentified comparable form
†Sphenophyllostachys – tentative report
†Sphenophyllum
- †Sphenophyllum angustifolium
- †Sphenophyllum verticillatum
†Sphenopteridium
- †Sphenopteridium dissectum
- †Sphenopteridium zaitzeffii – type locality for species
†Sphenopteris
- †Sphenopteris diphlebia – type locality for species
†Sphenosteges
- †Sphenosteges hispidus
†Spinilingula
- †Spinilingula prisca – type locality for species
†Spinofacia – type locality for genus
- †Spinofacia pectinatus – type locality for species
Fossilized shell of the Late Ordovician-Late Triassic brachiopod Spirifer
†Spirifer
- †Spirifer centronatus
- †Spirifer opimus
- †Spirifer rockymountanus
†Spiriferina
†Spirinella
- †Spirinella pauciplicata
Spirorbis
†Squamaria
†Squamularia – report made of unidentified related form or using admittedly obsolete nomenclature
†Stenolobulites
- †Stenolobulites simulator
- †Stenolobulites sinuosus
†Stenopora
- †Stenopora confusionensis
†Stenoporella
- †Stenoporella mineriensis
†Stenorhachis – tentative report
- †Stenorhachis genalticurvatus
†Stibaraster – type locality for genus
- †Stibaraster ratcliffei – type locality for species
Fossil preserved in situ of a Carboniferous tree-like club moss relative with attached Stigmaria rhizome system
†Stigmaria
- †Stigmaria ficoides
†Stigmariopsis
- †Stigmariopsis anglica
†Stolodus – or unidentified related form
- †Stolodus stola
†Straparollus
†Streblochondria
†Strebloplax
- †Strebloplax pertusa
†Streblopteria
- †Streblopteria montpelierensis
†Streblotrypa
- †Streblotrypa angulatum
†Streptelasma
†Striatifera
- †Striatifera brazeriana
†Strigambitus
- †Strigambitus utahensis
†Strobeus – or unidentified related form
†Sulcoretepora
†Supaia
- †Supaia rigida
†Symphysurina
- †Symphysurina cleora – or unidentified comparable form
- †Symphysurina globocapitella
- †Symphysurina illaenoides
- †Symphysurina spicata – or unidentified comparable form
- †Symphysurina uncaspicata
- †Symphysurina walcotti
†Symphysurus – tentative report
†Synarmocrinus
- †Synarmocrinus depressus – type locality for species
†Syntrophina
- †Syntrophina campbelli – or unidentified comparable form
- †Syntrophina carinifera
†Syntrophopsis
- †Syntrophopsis polita
- †Syntrophopsis transversa
Fossil of the Devonian tabulate coral Syringopora
†Syringopora
- †Syringopora aculeata
- †Syringopora surcularia
†Syringothyris
- †Syringothyris textus

T

†Tabulipora
- †Tabulipora atacta
- †Tabulipora carbonaria
- †Tabulipora ricta
- †Tabulipora sarcinula
- †Tabulipora stragula
†Taeniopteris
†Talpaspongia
- †Talpaspongia clavata
Fossil of the feeding trace ichnogenus Teichichnus
†Teichichnus – tentative report
†Telangium
- †Telangium affine
†Terranovella
†Tesselacauda
- †Tesselacauda depressa – or unidentified comparable form
†Testiispongia – type locality for genus
- †Testiispongia venula – type locality for species
†Testispongia
- †Testispongia venula
†Tetragraptus
- †Tetragraptus quadribrachiatus – or unidentified comparable form
Fossils of the burrow ichnogenus Thalassinoides
†Thalassinoides – tentative report
†Thamniscus
- †Thamniscus raribifurcatus
†Thamnosia – or unidentified comparable form
- †Thamnosia arctica – tentative report
†Timania
†Timaniella
- †Timaniella pseudocamerata
†Tingia
- †Tingia placida – type locality for species
†Tomagnostella
- †Tomagnostella exsculpta
†Tonkinella
- †Tonkinella breviceps
- †Tonkinella valida
†Torynifer
†Totiglobus – tentative report
- †Totiglobus lloydi
†Trace
- †Trace fossil
†Trachycheilus
- †Trachycheilus granulosus
- †Trachycheilus whirlwindensis
†Trematorthis – tentative report
†Tricitictes
†Tricrepicephalus
- †Tricrepicephalus teres
†Trigonocarpus
- †Trigonocarpus noeggerathii
†Trigonocerca
- †Trigonocerca typica
†Trigonocercella
- †Trigonocercella acuta
Illustration of a fossil of the Cambrian trilobite Trinodus
†Trinodus
†Triplagnostus
- †Triplagnostus gibbus
†Triplophylites
- †Triplophylites compressus
- †Triplophylites ellipticus
- †Triplophylites subcrassus
†Triticites
†Tritoechia
- †Tritoechia loganensis
- †Tritoechia sinuata
†Trocholites
†Trochophyllum – tentative report
†Trymataspis
- †Trymataspis depressa
Restoration of the Permian reptile relative Tseajaia
†Tseajaia
- †Tseajaia campi – type locality for species
†Tulepyge
- †Tulepyge tulensis – type locality for species
†Tumicephalus
- †Tumicephalus depressus
†Tuzoia
- †Tuzoia argenta
- †Tuzoia guntheri
- †Tuzoia retifera
†Tympanuella
- †Tympanuella transversa

U

†Ufimia
†Ulrichodina – tentative report
†Uromystrum
- †Uromystrum validum – or unidentified comparable form
†Utagnostus
- †Utagnostus trispinulus
†Utahacanthus – type locality for genus
- †Utahacanthus guntheri – type locality for species
†Utahcaris
- †Utahcaris orion
Life restoration of the Carboniferous amphibian Utaherpeton
†Utaherpeton – type locality for genus
- †Utaherpeton franklini – type locality for species
†Utaspis
- †Utaspis marjumensis