List of the Paleozoic life of Iowa

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

A

 * †Abatocrinus
 * †Acidaspis
 * †Aclisina
 * Monobathrida - Actinocrinites.JPG †[[Actinocrinites]]
 * †Actinocrinites gibsoni
 * †Actinocrinites jugosus
 * †Actinocrinites lowei
 * †Actinocrinites pernodosus
 * †Actinocrinites probolos
 * †Actinopteria – tentative report
 * †Actinostroma
 * †Actinostroma clathratum
 * †Acutatheca
 * †Acutatheca propira
 * †Adocetocystis
 * †Adolfia
 * †Aechmina
 * †Aechmina cuspidata
 * †Aechmina ionensis
 * †Aechmina maquiketensis
 * †Aechmina taurea
 * †Agassizodus
 * †Agassizodus variabilis
 * †Agelacrinites
 * †Aglaocrinus
 * †Aglaocrinus compactus
 * †Allanella
 * †Allanella allani
 * †Allanella annae
 * †Allanella cardinalis
 * †Allenella
 * †Allenella allani
 * †Allenella annae
 * †Allocrinus
 * †Allocrinus ornatus
 * †Allocrinus subglobosus
 * †Allorhynchus
 * †Allorhynchus currei – or unidentified comparable form
 * †Allozygocrinus
 * †Allozygocrinus dubuquensis
 * †Alveolites
 * †Ambocoelia
 * †Ambocoelia louisianaensis
 * †Ambocoelia minuta
 * †Ambonychia
 * †Americoncha
 * †Americoncha marginata
 * †Amphicoelia
 * †Amphicyrtoceras
 * †Amphipora
 * †Amphipora pervesiculata
 * †Amplexus
 * †Anartiocystis
 * †Anastrophia
 * †Anataphrus
 * †Anematina
 * †Anematina conica
 * †Angyomphalus
 * †Angyomphalus lens
 * †Angyomphalus penelenticulata – type locality for species
 * †Anisotrypa
 * †Anomphalus
 * †Anthracospirifer
 * †Anthracospirifer pellaensis
 * †Antiquatonia
 * †Antirhynchonella
 * †Antirotella
 * †Antirotella kindlei – type locality for species
 * †Aorocrinus
 * †Aparchites
 * †Aparchites barbatus
 * †Aparchites carinatus
 * †Aparchites chatfieldensis
 * †Aparchites ellipticus
 * †Aparchites fimbriatus
 * †Aparchites macrus
 * †Aparchites paratumida
 * †Aphelecrinus
 * †Apycnodiscus
 * †Arabellites
 * †Arachnophyllum
 * †Archaeocalyptocrininus
 * †Archaeocalyptocrininus iowensis
 * †Archaeocalyptocrininus nodosus
 * †Archaeocalyptocrinus
 * †Archaeocalyptocrinus iowensis
 * †Archaeocalyptocrinus nodosus
 * †Archaeocrinus
 * †Archaeocrinus obconicus
 * †Archaeogastropod
 * †Archinacella
 * †Archinacella rotunda
 * Arctinurus boltoni.jpg †[[Arctinurus]]
 * †Arctomeristina
 * †Arisaigia
 * †Arrectocrinus
 * †Arrectocrinus iowensis
 * †Arthroxylon
 * †Asphaltinella
 * †Asterophyllites
 * †Asterophyllites multifolia
 * †Asthenophyllum
 * †Astraeospongium
 * †Astreptodictya
 * †Astrocystites
 * †Astrocystites ottawaensis – tentative report
 * †Atelodictyon
 * †Atelodictyon masoncityense – type locality for species
 * †Athyris
 * †Athyris cedarensis
 * †Athyris crassicardinalis
 * †Athyris fultonensis – or unidentified comparable form
 * †Athyris simplex
 * †Athyris spiriferiodes
 * †Athyris vitatta
 * †Athyris vittata
 * †Athyris zonulata
 * †Atribonium
 * †Atribonium nora
 * †Atribonium paupera
 * †Atribonium prolifica
 * †Atribonium subovata
 * †Atribonium swallovi
 * †Atrypa
 * Atrypa reticularis pedunculate Gondelsheim CRF.jpg †[[Atrypa reticularis]]
 * †Atrypa reticularus
 * †Atryparia
 * †Atryparia varicostata
 * †Atrypoidea
 * †Aulacella
 * †Aulocopella
 * †Aulocopella dactylos – type locality for species
 * †Aulocopella probolos – type locality for species
 * †Aulocopella scelidos – type locality for species
 * †Aviculopecten
 * †Aviculopecten marbuti – or unidentified comparable form

B

 * Bairdia
 * †Bairdiocypris
 * †Bairdiocypris granti
 * †Bairdocypris
 * †Bairdocypris granti
 * †Basseleratia
 * †Basseleratia typa
 * †Bassleratia
 * †Bassleratia typa
 * †Batostomella
 * †Baylea
 * †Baylea trifibra – type locality for species
 * †Beecheria
 * †Beecheria chouteauensis
 * †Belemnocrinus
 * Bellerophon umbilicalis.jpg †[[Bellerophon (genus)|Bellerophon]]
 * †Bellerophon blairi
 * †Bellerophon panneus
 * †Bellerophon patersoni
 * †Bellerophon vinculatus
 * †Bellornatia
 * †Bellornatia tricollis
 * †Belodina
 * †Belodina compressa
 * †Beloitoceras – tentative report
 * †Beloitoceras discrepana
 * †Bembexia
 * †Bembexia minima
 * †Bensbergia
 * †Bensbergia pulchra – type locality for species
 * †Beyrichia
 * †Beyrichia irregularis
 * †Bighornia
 * †Blothrocrinus
 * †Bobbodus
 * †Bobbodus schaefferi
 * †Bolicrinus
 * †Bolicrinus deflatus
 * †Bolicrinus globosus
 * †Bollia
 * †Bollia regularis
 * †Bollia ruthae
 * †Bollia subaequata
 * Britannica Echinoderma 5.jpg †[[Bothriocidaris]]
 * †Bothriocidaris maquoketensis
 * †Botryocrinus
 * †Botryocrinus thomasi – type locality for species
 * †Brachythyris
 * †Brachythyris burlingtonensis – or unidentified comparable form
 * †Brachythyris chouteauensis
 * †Brachythyris peculiaris
 * †Brachytomaria
 * †Brachytomaria semele
 * †Breviphillipsia
 * †Brockocystis
 * †Brockocystis nodosaria
 * †Bromidella
 * †Bromidella depressa
 * †Bromidella rhomboides
 * †Bryantodina
 * †Bryantodina typicalis
 * †Bucanella
 * †Bucanella conradi
 * †Bucanopsis
 * †Bucanopsis lirata
 * †Bullatekka
 * †Bullatekka granilabiatus
 * †Bullatella
 * †Bullatella granilabiatus
 * Trilobite - Bumastus reconstruction 3d.jpg †[[Bumastus]]
 * †Buranella
 * †Buxtonia – tentative report
 * †Byrsolopsina
 * †Byrsolopsina centipunctata
 * †Byrsolopsina normella
 * †Byrsolopsina ovata
 * †Byrsolopsina planilateralis
 * Bythocypris
 * †Bythocypris curta
 * †Bythocypris furnishi

C

 * †Caenanoplia
 * †Caenanoplia logani
 * †Calamocarpon
 * †Calamocarpon insignis
 * †Calceocrinus
 * †Calceocrinus levorsoni
 * †Calcisphaera
 * †Calcisphaera laevis
 * †Calliocrinus
 * †Calliocrinus longispinus
 * †Callocrinus
 * †Callocrinus longispinus
 * †Callocystites
 * †Calvinaria
 * †Calvinaria ambigua
 * †Calvinaria bransoni
 * †Calvustrigis – tentative report
 * Calymene clavicula dorsal.jpg †[[Calymene]]
 * †Camarophorella
 * †Camarophorella lenticularis
 * †Camarotoechia
 * †Camarotoechia chemungensis
 * †Camarotoechia chouteauensis
 * †Camarotoechia crassiplicata
 * †Camarotoechia perplexa
 * †Camarotoechia quadricostatum
 * †Camarotoechia saxatilis
 * †Camarotoechia saxatillis
 * †Camarotoechia tuta
 * †Camerella
 * †Carabocrinus
 * †Carabocrinus radiatus
 * †Carabocrinus slocomi
 * †Cardiola
 * †Cardiola lyoni
 * †Carinatrypa
 * †Carinatrypa dysmorphstrota
 * †Cariniferella
 * †Cariniferella iowensis
 * †Carpocrinus
 * †Carpocrinus bodei
 * †Caryocrinites
 * Museum Mensch und Natur - catenipora.jpg †[[Catenipora]]
 * †Ceratocephala
 * †Ceratopsis
 * †Ceratopsis humilinoda
 * †Ceratopsis quadrifida
 * †Ceratopsis trilobis
 * †Ceraurus
 * †Cerithioides
 * †Cerithioides judiae
 * †Characterophyllum
 * †Characterophyllum nanum
 * †Charactoceras
 * †Charactophyllum
 * †Charactophyllum nanum
 * †Charionella
 * †Charionella nortoni
 * Trilobite Ordovicien 8127.jpg †[[Cheirurus]]
 * †Chomatodus
 * †Chomatodus inconstans
 * †Chonetes
 * †Chonetes glenparkensis
 * †Chonetes illinoisensis
 * †Chonetes logani
 * †Chonetes multicosta
 * †Chonetes multicostata
 * †Chonetes ornatus
 * †Chonetina
 * †Chonetinella
 * †Chonetipustula
 * †Chonetipustula concentrica
 * †Chonopectus
 * †Chonopectus fischeri
 * †Chonophyllum
 * †Clathrocoilona
 * †Clathrocoilona involuta – type locality for species
 * †Clathrodictyon
 * †Cleiocrinus
 * †Cleiocrinus regius
 * †Cleiothyridina
 * †Cleiothyridina crassicardinalis – or unidentified related form
 * †Cleiothyridina glenparkensis – or unidentified comparable form
 * †Cleiothyridina incrassata – or unidentified comparable form
 * †Cleiothyridina sublamellosa
 * †Climacoconus
 * †Climacoconus pumilus
 * Climacograptus wilsoni Graptolite Fossils from Dob%27s Linn Scotland.jpg †[[Climacograptus]]
 * †Climacograptus pumilis
 * †Climacograptus typicalis
 * †Clinolithes
 * †Clinopistha
 * †Clintonella – tentative report
 * †Clorinda
 * †Cochliodus
 * †Cochliodus occidentalis
 * †Coelospira
 * †Coeloterorhynchus
 * †Coeloterorhynchus schucherti
 * †Coeloterorhynchus subacuminata
 * †Coeloterorhynchus subacuminatus
 * †Coenites
 * †Composita
 * †Composita humilis – tentative report
 * †Composita immatura – or unidentified comparable form
 * †Composita trinuclea
 * †Compsocrinus
 * †Concavicaris
 * †Concavicaris sinuata – or unidentified comparable form
 * †Conocardium
 * †Conotreta
 * †Conularia
 * †Coolinia
 * Cornulites cellulosus.jpg †[[Cornulites]]
 * †Costistricklandia
 * †Costistricklandia castellana
 * †Costistricklandia multilirata
 * †Cotylacrina
 * †Cotylacrina sandra
 * †Cranaena
 * †Cranaena amana
 * †Cranaena arcuosa
 * †Cranaena calvini
 * †Cranaena depressa
 * †Cranaena elia
 * †Cranaena famelica
 * †Cranaena inflata
 * †Cranaena infrequens
 * †Cranaena iowensis
 * †Cranaena jacunda
 * †Cranaena lata
 * †Cranaena littleonensis
 * †Cranaena littletonensis
 * †Cranaena maculata
 * †Cranaena marsii
 * †Cranaena micula
 * †Cranaena navicella
 * †Cranaena occidentalis
 * †Cranaena pachytesta
 * †Cranaena parvirostra
 * †Cranaena rhomboidialis
 * †Cranaena rockfordensis
 * †Cranaena romingeri
 * †Cranaena seminula
 * †Cranaena subcylindrica
 * †Cranaena subglobosa
 * †Cranaena subglossa
 * †Cranaena subgobulosa
 * †Cranaena subouata
 * †Cranaena subovata
 * †Cranaena thomasi
 * †Cranaenella
 * †Crania
 * †Crania famelica
 * †Crassiproetus
 * †Crassiproetus arietinus
 * †Crassiproetus bumastoides
 * †Crassiproetus occidens
 * †Crassiproetus searighti
 * †Cremacrinus
 * †Cremacrinus gerki
 * †Cremacrinus guttenbergensis
 * †Cremacrinus punctatus – or unidentified related form
 * †Cremacrinus type locality for species – informal
 * †Cribanocrinus
 * †Crotalocrinintes
 * Crinoidea - Crotalocrinites sp. .JPG †[[Crotalocrinites]]
 * †Crurithyris
 * †Cryptophyllus
 * †Cryptophyllus oboloides
 * †Cryptophyllus sulcatus
 * †Ctenobolbina
 * †Ctenobolbina emaciata
 * †Ctenobolbina maquoketensis
 * †Ctenodonta
 * †Ctenodonta anatina
 * †Ctenodonta calvini
 * †Cupularostrum
 * †Cupularostrum contracta
 * †Cupularostrum saxatilis
 * †Cupularostrum saxatillis
 * †Cupulocorona
 * †Cupulocrinus
 * †Cupulocrinus angustatus
 * †Cupulocrinus conjugans – or unidentified related form
 * †Cupulocrinus crossmani
 * †Cupulocrinus latibrachiatus – or unidentified related form
 * †Curtognathus
 * †Cusacrinus
 * †Cyathaxonia
 * †Cyathaxonia arcuatus
 * [[File:Cyathocrinites multibrachiatus fossil crinoid (Mississippian; Crawfordsville, Indiana, USA) 2 (17385978065).jpg|thumb|upright=0.3|Fossilized calyx and partial stem of the Silurian-Permian crinoid ("sea lily") Cyathocrinites]] †[[Cyathocrinites]]
 * †Cyathocrintes
 * †Cyathocrintes striatissimus – or unidentified comparable form
 * †Cyathophyllum
 * †Cyclocrinites
 * †Cyclocrinites dactilioides
 * †Cyclocrinites dactioloides
 * †Cyclocystoides
 * †Cyclonema
 * †Cyclonema bilix
 * †Cyclonema minuta
 * †Cyclora
 * †Cynopodius
 * †Cyphaspis
 * †Cypricardella
 * †Cypricardinia
 * †Cypricardinia sulcifera
 * †Cyrtia
 * †Cyrtia exporrecta
 * †Cyrtina
 * †Cyrtina inulta
 * †Cyrtina iowaensis
 * †Cyrtina triquetra
 * †Cyrtina umbonata
 * †Cyrtodonta
 * †Cyrtolites
 * †Cyrtospira
 * Cyrtospirifer verneuili duo.jpg †[[Cyrtospirifer]]
 * †Cyrtospirifer disjunctus
 * †Cyrtospirifer whitneyi
 * †Cystiphyllum
 * †Cystiphyllum mundulum
 * †Cystodictya
 * †Cytocrinus

D

 * †Dalejina
 * †Dalmanella
 * †Dalmanella edgewoodensis – or unidentified comparable form
 * SilurianTrilobite.jpg †[[Dalmanites]]
 * †Dapsilodus
 * †Dapsilodus mutatus
 * †Dawsonoceras
 * †Decadocrinus
 * †Decadocrinus crassidactylus – type locality for species
 * †Decadocrinus pachydactylus – type locality for species
 * †Decadocrinus spinulifer – type locality for species
 * †Decaschisma
 * †Dechenella
 * †Dechenella haldemani – or unidentified comparable form
 * †Dechenella nortoni
 * †Dechenella prouti
 * †Dechenella rowi – or unidentified comparable form
 * Deiphon forbesi cropped.png †[[Deiphon]]
 * †Delocrinus
 * †Delocrinus vulgatus
 * †Deltaherpeton – type locality for genus
 * †Deltaherpeton hiemstrae – type locality for species
 * †Delthyris – tentative report
 * †Deltodus
 * †Deltodus spatulatus
 * †Dendrocrinus
 * †Dendrocrinus casei
 * †Dendrocrinus curvijunctus – or unidentified related form
 * †Dendrocrinus oswegoensis
 * Dentalium octangulatum 01.JPG †[[Dentalium (genus)|Dentalium]]
 * †Dentalium grandaevum
 * †Derbyia
 * †Desquamatia
 * †Desquamatia brandonensis
 * †Desquamatia independensis
 * †Desquamatia randalia
 * †Desquamatia rotunda
 * †Desquamatia rusica
 * †Desquamatia scutiformis
 * †Desquamatia waterlooensis
 * †Devonatrypa
 * †Devonatrypa brandonensis
 * †Devonatrypa pronis
 * †Devonatrypa trowbridgei
 * †Devonatrypa waterlooensis
 * †Devonochonetes
 * †Devonochonetes calivini
 * †Devonoproductus
 * †Devonoproductus reticulocostus
 * †Devonoproductus vulgaris
 * †Devonoproductus walcotti
 * †Diamphidiocystis
 * †Diceromyonia
 * †Dichacaenia
 * †Dichacaenia harberti
 * †Dichocrinus
 * †Dicoelosia
 * †Dicranella
 * †Dicranella bicornis
 * †Dicranella marginata
 * †Dicranella simplex
 * †Dicranella spinosa
 * †Dicranella typa
 * †Dicranopeltis
 * †Dictyoclostus
 * †Dictyotomaria
 * †Dictyotomaria quasicapillaria – type locality for species
 * †Dielasma
 * †Dielasma burlingtonensis
 * †Dielasma chouteauensis
 * †Dielasma formosum
 * †Dimerocrinites
 * †Dimerocrinites hopkintonensis
 * †Dimerocrinites pentangularis
 * †Dimerocrinites sculptus
 * †Dinobolus
 * †Dinolobus
 * †Dinorthis
 * †Diopatraites
 * †Diphyphyllum
 * †Diploblastus
 * †Diploblastus glaber
 * Diplograptus simplex.png †[[Diplograptus]]
 * †Diplograptus modestus – or unidentified comparable form
 * †Diplophyllum
 * †Diplosphaerina
 * †Diplosphaerina inaequalis
 * †Discosorus
 * †Disphyllum
 * †Disphyllum conjugans – type locality for species
 * †Disphyllum dispassum
 * †Disphyllum floydense
 * †Disphyllum iowensis – type locality for species
 * †Disphyllum tubiforme
 * †Dolerorthis
 * †Donaldina – tentative report
 * †Dorycrinus
 * †Dorycrinus gouldi
 * †Dorycrinus mississippiensis
 * †Douvillina
 * †Douvillina arcuata
 * †Douvillina cayuta
 * †Douvillina delicata
 * †Douvillina distans
 * †Douvillina maxima
 * †Douvillina navicula
 * †Douvillina oxycostratum
 * †Douvillina variabilis
 * †Douvillinaria
 * †Douvillinaria delicata
 * †Douvillinaria perversa
 * †Douvillinaria variabilis
 * †Douvillinaria variablis
 * †Drepanoistodus
 * †Drepanoistodus suberectus
 * †Dudleyaspis
 * †Dvorakia
 * †Dvorakia chattertoni – type locality for species

E

 * †Earlandia
 * †Ecclimadictyon
 * †Ecclimadictyon fastigiatum
 * †Echinocoelia
 * †Echinocoelia halli
 * †Echinoconchus
 * †Ectenocrinus
 * †Ectenocrinus raymondi
 * †Ectenocrinus simplex
 * †Ectodemites
 * †Ectodemites primus
 * †Ectogrammysia
 * †Ectogrammysia hannibalensis
 * Edestus protopirata1DB.jpg †[[Edestus]]
 * †Edestus crenulata
 * †Edestus mirus – type locality for species
 * †Edmondia
 * †Edmondia jejunus
 * †Eldredgeops
 * †Eldredgeops rana
 * †Eleutherokomma
 * †Eleutherokomma jasperensis
 * †Elita
 * †Elita diversa
 * †Elita inconsueta
 * †Elita johnsonensis
 * †Elita minor
 * †Elita subundifera
 * †Elita urbana
 * †Ellesmeria
 * †Ellesmeria scobeyi
 * †Ellesmeroceras
 * †Ellesmeroceras luthei
 * †Ellesmeroceras thomasi
 * †Emanuella
 * †Emanuella ii – report made of unidentified related form or using admittedly obsolete nomenclature
 * †Emanuella meristoides
 * †Emanuella sublineata
 * †Emphereaster
 * †Emphereaster missouriensis
 * †Encrinurus
 * Endoceras.JPG †[[Endoceras]]
 * †Endostaffella
 * †Endostaffella discoidea
 * †Endothyra
 * †Endothyra obsoleta – tentative report
 * †Endothyranella
 * †Enoploura
 * †Enoploura wetherbyi
 * †Enteletes
 * †Entelophyllum
 * Eocaudina
 * †Eocaudina septaforaminalis – type locality for species
 * †Eochonetes
 * †Eochonetes aspera
 * †Eochonetes dignata – type locality for species
 * †Eochonetes recedens
 * †Eodictyonella
 * †Eolissochonetes
 * †Eomartiniopsis
 * †Eomartiniopsis rostrata
 * †Eoparisocrinus
 * †Eoparisocrinus crossmani
 * †Eophacops
 * †Eoplectodonta
 * †Eoschmidtella
 * †Eoschmidtella umbonata
 * †Eospirifer
 * †Eospirifer radiatus
 * †Eospirigerina
 * †Eospirigerina putilla – or unidentified comparable form
 * †Eostrophalosia
 * †Eostrophalosia independensis
 * †Eostrophalosia inexpectans
 * †Eostrophalosia rockfordensis
 * †Eosyringothyris
 * †Eosyringothyris aspera
 * †Eosyringothyris occidentalis
 * †Eosyringothyris thomasi
 * †Eosyringothyris triangularis
 * †Ephippiorthoceras
 * †Eridoconcha
 * †Eridoconcha gibbera
 * †Eridoconcha punctata
 * †Eridotrypa
 * †Erismacanthus
 * †Erismacanthus barbatus
 * †Erismodus
 * †Erismodus radicans
 * †Escharopora
 * EucalyptocrinitesCalyx.jpg †[[Eucalyptocrinites]]
 * †Eucalyptocrinites depressus
 * †Eucalyptocrinites inornatus
 * †Eucalyptocrinites ornatus – or unidentified comparable form
 * †Eucalyptocrinites proboscidalis
 * †Eukloedenella
 * †Eukloedenella richmondensis
 * †Eumetria
 * †Eumetria iowensis
 * †Eumetria osagensis
 * †Eumorphocystis
 * †Eunema
 * †Eunema quadrisulcata
 * Euomphalus fossil cropped.png †[[Euomphalus]]
 * †Euomphalus angularis
 * †Euomphalus obtusus
 * †Euphemites
 * †Euphemites lentiformis
 * †Euphemites urei
 * †Euprimitia
 * †Euprimitia celata
 * †Euprimitia flores
 * †Euprimitia labiosa
 * †Euprimitia linepunctata
 * †Euprimitia minuta
 * †Euprimitia sanctipauli
 * †Euptychocrinus
 * †Euptychocrinus skopaios
 * †Eurychilina
 * †Eurychilina incurva
 * †Eurychilina minutifoveata
 * †Eurychilina partifimbriata
 * †Eurychilina reticulata
 * †Eurychilina subradiata
 * †Eurychilina ventrosa
 * †Eutaxocrinus
 * †Eutaxocrinus gracilis
 * †Exocrinus
 * †Exocrinus multirami

F

 * †Fardenia – tentative report
 * †Favosites
 * †Fenestella
 * †Fenestrellina
 * †Ferganella
 * †Fistulipora
 * †Flabellitesia
 * †Flabellitesia flabellites
 * Flexicalymene-ouzregui-rolled.jpg †[[Flexicalymene]]
 * †Floweria
 * †Floweria altirostris
 * †Floweria orthoplicata
 * †Floweria prava
 * †Floyda
 * †Floyda concentrica
 * †Fourstonella

G

 * †Galateacrinus
 * †Galateacrinus gossameri
 * †Gilmocrinus
 * †Girtyella
 * †Girtyella indianse
 * †Glabrocingulum
 * †Glabrocingulum angulosa – type locality for species
 * †Glabrocingulum minutum – type locality for species
 * †Glaphyrites
 * †Glossites
 * †Glyptorthis
 * †Glyptorthis pulchra – type locality for species
 * †Glyptorthis subcircularis – type locality for species
 * †Gomphocystites
 * Goniatitidae - Goniatites species.JPG †[[Goniatites]]
 * †Goniocrinus
 * †Goniophyllum
 * †Goniophyllum pyramidale
 * †Gorgonophontes
 * †Gorgonophontes peleron
 * †Graffhamicrinus
 * †Graffhamicrinus magnijkus
 * †Graffhamicrinus subcoronatus
 * †Grammysia
 * †Grammysia amygdalinus
 * †Gravicalymene
 * †Greenops
 * †Greenops barrisi
 * †Greenops fitzpatricki
 * RugosaOrdovician.jpg †[[Grewingkia]]
 * †Gypidula
 * †Gypidula cornuta
 * †Gypidula munda
 * †Gypidula occidentalis
 * †Gypidula papyracea
 * †Gypidula parva
 * †Gypidulina
 * †Gyroceras

H
†Hyolithes
 * †Hadrorhynchia
 * †Hadrorhynchia solon
 * †Haeretocrinus
 * †Haeretocrinus missouriensis
 * †Hagnocrinus
 * †Hallatia
 * †Hallatia convexa
 * †Hallatia duplicata
 * †Hallatia particylincrica
 * †Hallatia particylindrica
 * †Hallicystis
 * †Halliella
 * †Halliella magnipunctata
 * Hallopora multitabulata fossil bryozoan (Ordovician; Frankfort IL.jpg †[[Hallopora]]
 * †Halysiocrinus
 * †Halysiocrinus barrisi
 * †Halysiocrinus elephantinus – type locality for species
 * †Halysites
 * †Hammatostroma
 * †Hammatostroma albertense
 * †Harpidella – tentative report
 * †Harpidella brandonensis
 * †Harpidium
 * †Harpidium luckeyensis – or unidentified related form
 * †Harpidium maquoketa
 * †Hedeina
 * †Heliolites
 * Heliophyllum halli Bethany Center Centerfield 2.jpg †[[Heliophyllum]]
 * †Heliophyllum solidum
 * †Helliella
 * †Helliella magnipunctata
 * †Hemicystites
 * †Hemiphragma
 * †Hemiplethorhynchus
 * †Hemiplethorhynchus subovatum
 * †Hermatostroma
 * †Hermatostroma polymorphum
 * †Hernodia
 * †Hesperidella
 * †Hesperidella initialis
 * Hexagonaria percarinata close view.JPG †[[Hexagonaria]]
 * †Hexagonaria bassleri
 * †Hexagonaria inequalis
 * †Hexagonaria oweni
 * †Hexagonaria whitfieldi
 * †Hibbardella
 * †Hibbardella subacoda
 * †Hindella
 * †Hindia
 * †Hindia parva – tentative report
 * †Hindia sphaeroidalis
 * †Holcocrinus
 * Holopeidae - Holopea praestans.JPG †[[Holopea]]
 * †Holopea iowaensis
 * †Homacanthus
 * †Homacanthus delicatulus
 * †Homoeospira
 * †Homotrypella
 * †Hormotoma
 * †Hormotoma gracilis
 * †Howellella
 * †Hudsonaster
 * †Huronia
 * †Hustedia
 * †Hyattidina
 * †Hybocrinus
 * †Hybocrinus conicus
 * †Hyolithes parviusculus
 * †Hypergonia
 * †Hypergonia percarinata
 * †Hypothyridina
 * †Hypothyridina emmonsi
 * †Hypothyridina intermedia
 * †Hypothyridina magister
 * †Hypselocrinus
 * †Hypsitycha
 * †Hypsitycha hybrida
 * †Hysitycha
 * †Hysitycha neenah
 * †Hystriculina

I

 * †Ianthinopsis
 * †Ianthinopsis pinguis – type locality for species
 * †Icriodus
 * †Icriodus calvini – type locality for species
 * †Icriodus latericrescens
 * †Icriodus nodosus
 * †Icriodus orri – type locality for species
 * †Icriodus subterminus
 * †Icthyocrinus
 * †Idiognathodus
 * †Idiognathodus attenuatus – type locality for species
 * †Idiognathodus claviformis
 * †Idiognathodus iowaensis – type locality for species
 * †Ignoceras
 * †Ignoceras undata
 * †Indospirifer
 * †Indospirifer orestes
 * Iniopteryxrushlaui.JPG †[[Iniopteryx]]
 * †Iniopteryx rushlaui
 * †Iniopteryx tedwhitei
 * †Iocrinus
 * †Iowacystis
 * †Iowacystis sagittaria
 * †Iowaphyllum
 * †Iowaphyllum johanni
 * †Iowatrypa
 * †Iowatrypa americana
 * †Iowatrypa owenensis
 * †Ischadites
 * †Isorthis
 * †Isorthoceras
 * †Isorthoceras sociale
 * Isotelus brachycephalus.JPG †[[Isotelus]]

J

 * †Juresania

K

 * †Kaskia
 * †Kayoceras
 * †Kiesowia
 * †Kiesowia binoda
 * †Kiesowia insolens
 * †Kinocrinus
 * †Kinocrinus inflatus
 * Kionoceras doricum.JPG †[[Kionoceras]]
 * †Kionoceras decorahense – type locality for species
 * †Kirkidium
 * †Kitikamispira – tentative report
 * †Kitikamispira perstrialis – type locality for species
 * †Knightella
 * †Knightella shumardiana – type locality for species
 * †Kosovopeltis
 * †Kosovopeltis acamas
 * †Krausella
 * †Krausella arcuata
 * †Krausella curtispina
 * †Krausella inaequalis
 * †Krinocrinus
 * †Krinocrinus inflatus

L

 * †Laccoprimitia
 * †Laccoprimitia elegantula
 * †Laccoprimitia fillmorensis
 * †Lacertasterias – type locality for genus
 * †Lacertasterias elegans – type locality for species
 * †Laddella
 * †Laddella insueta
 * †Ladogioides
 * †Ladogioides solon
 * Laevidentalium
 * †Lamottia
 * †Lamottia heroensis
 * †Lampterocrinus
 * †Lanecrinus – tentative report
 * †Leangella
 * †Lecanocrinus
 * †Lecathylus
 * †Lecathylus gregarius
 * †Lechritochoceras
 * †Leioclema
 * †Leioclema occidens
 * †Leiorhynchus
 * †Leiorhynchus argenteum
 * †Leiorhynchus gosseleti
 * †Leiorhynchus iris
 * †Leperditella
 * †Leperditella dorsicornis
 * †Leperditella fryei
 * †Leperditella macra
 * †Leperditella millepunctata
 * †Leperditella persimilis
 * †Leperditella sacceliformis
 * †Leperditia
 * †Lepidocyclus
 * †Lepidoleptaena – or unidentified related form
 * †Leptaena
 * †Leptaena rhomboidalis
 * †Leptagonia
 * †Leptagonia analoga
 * †Leptellina
 * †Leptobolus
 * †Leptobolus occidentalis
 * †Leptodesma
 * †Leptodesma acutilaris
 * †Leptodesma subovata
 * †Leptopora
 * †Leptopora typa
 * †Leptoptygma
 * †Leptoptygma oligospira – type locality for species
 * †Leptostrophia – tentative report
 * †Leptotrypella
 * †Lichenalia
 * †Lichenocrinus
 * Lingula anatina 7 .JPG †[[Lingula (genus)|Lingula]]
 * †Lingula changi
 * †Lingula cuneata
 * †Lingula fragila
 * †Lingula milwaukeensis – or unidentified comparable form
 * †Lingula milwaukiensis
 * †Lingulodiscina
 * †Lingulodiscina marginalis
 * †Linocrinus
 * †Linoporella
 * †Linoproductus
 * †Linoproductus ovatus
 * †Liospira
 * †Liospira micula
 * †Liospira spicula – or unidentified comparable form
 * †Litostrobus
 * †Litostrobus iowensis
 * †Litostrobus paulus
 * †Lonchodus – tentative report
 * †Lophophyllidium
 * †Lophospira
 * †Lophospira depauperata
 * †Lorangerella
 * †Lorangerella gregaria
 * †Loxonema
 * †Lumbriconereites
 * †Luxocrinus
 * †Luxocrinus simplex
 * †Lyonicrinus
 * †Lyriocrinus
 * †Lysocystites
 * †Lysocystites nodosus
 * †Lytospira

M

 * †Macgeea
 * †Macgeea camplanulata – type locality for species
 * †Macgeea concinnula – type locality for species
 * †Macgeea culmula
 * †Macgeea solitaria
 * †Macrocrinus
 * †Macrocrinus mundulus
 * Macrocypris
 * †Macrocypris kayi
 * †Macrocyproides
 * †Macrocyproides clermontensis
 * †Macronotella
 * †Macronotella arcta
 * †Macronotella scofeldi
 * †Macronotella scofieldi
 * †Macropotamorhynchus
 * †Macropotamorhynchus tuta
 * †Macrostylocrinus
 * †Macrostylocrinus compressus
 * †Macrostylocrinus obpyramidalis – or unidentified comparable form
 * †Macrostylocrinus vermiculatus
 * †Manicrinus
 * Gephuroceratidae - Manticoceras species.JPG †[[Manticoceras]]
 * †Manticoceras regulare
 * †Manticrinus
 * †Maquoketacrinus
 * †Maquoketacrinus ornatus
 * †Maratia
 * †Maratia mara
 * †Maratia micula
 * †Marsupiocrinus
 * †Marsupiocrinus primaevus
 * †Mediospirifer
 * †Megalomoidea
 * †Megamyonia
 * †Megamyonia unicostata
 * †Megastrophia
 * †Megastrophia profunda
 * †Megistocrinus
 * †Megistocrinus pernodosus
 * †Melocrinites
 * †Merista
 * Meristella two views.png †[[Meristella]]
 * †Meristella parva
 * †Meristina
 * †Merocrinus
 * †Mesoblastus – or unidentified comparable form
 * †Mesolobus
 * †Metaconularia
 * †Metalonchodina
 * †Metalonchodina deflecta – type locality for species
 * †Michelia
 * †Michelinoceras
 * †Microcardinalia
 * †Milleratia
 * †Milleratia cincinnatiensis
 * †Milleratia cincinnattiensis
 * †Mirifusella – type locality for genus
 * †Mirifusella fortunata – type locality for species
 * †Modiomorpha
 * †Monomerella
 * †Murchisonia
 * †Myalina
 * †Mycterops
 * †Mycterops whitei – type locality for species
 * †Myeinocystites
 * †Myelodactylus
 * †Mystrocephala
 * †Mystrocephala pulchra – or unidentified comparable form
 * †Mystrocephala raripustulosus
 * †Mytilarca

N

 * †Nactocrinus
 * †Nalivkinia – tentative report
 * †Nataliana – type locality for genus
 * †Nataliana sinuata – type locality for species
 * Neritopsidae - Naticopsis.JPG †[[Naticopsis]]
 * †Naticopsis depressa – type locality for species
 * †Neopanderodus
 * †Neospirifer
 * †Neozaphrentis
 * †Neozaphrentis pellaensis
 * †Nervostrophia
 * †Nervostrophia calvini
 * †Nervostrophia canace
 * †Nervostrophia contaderoensis
 * †Nervostrophia extensa
 * †Nervostrophia multinervosa
 * †Nervostrophia rockfordensis
 * †Nervostrophia solida
 * †Nervostrophia thomasi
 * †Newberria
 * †Newberria cordiforme
 * †Newberria johanni
 * †Ningulella
 * †Ningulella paucisulcata
 * †Nodambichilina
 * †Nodambichilina symmetrica
 * †Nucellangium
 * †Nucellangium glabrum
 * †Nucleospira
 * †Nucleospira barrisi
 * Nuculidae - Nucula piacentina.jpg [[Nucula]]
 * †Nucula glanparkensis
 * †Nucula iowensis
 * Nuculana
 * †Nuculana sacata
 * †Nuculites
 * †Nuculites neglectus
 * †Nuculopsis

O

 * †Odontopleura
 * †Oepikina
 * †Oistodus
 * †Oistodus venustus
 * †Onniella
 * †Onniella quadrata
 * OnychodusDB15.jpg  †[[Onychodus]]
 * †Opikatia
 * †Opikatia emaciata
 * †Opikatia rotunda
 * †Opoa
 * †Orbiculoidea
 * †Orbiculoidea telleri
 * †Orbiculoidea varsoviensis
 * †Orbiculoidea wardi
 * †Orecopia
 * †Orecopia circinatus – type locality for species
 * †Oriostoma
 * †Orthoceras
 * †Orthoceras indianense
 * †Orthodesma
 * †Orthograptus
 * †Orthograptus eucharis
 * †Orthograptus truncatus
 * †Orthonychia
 * †Orthonychia vomerium
 * †Orthospirifer
 * †Orthospirifer capax
 * †Orthospirifer euruteines
 * †Orthospirifer iowensis
 * †Orthospirifer parryanus
 * †Orthotetes
 * †Orthotetes kaskaskiensis
 * †Otarion – tentative report
 * †Oulodus
 * †Oulodus abbreviata – type locality for species
 * †Oulodus serratus
 * †Ovatia
 * †Ovatia laevicostata
 * †Ovatia ovata
 * †Ozarkodina
 * †Ozarkodina campbelli – type locality for species
 * †Ozarkodina delicatula
 * †Ozarkodina raaschi

P

 * †Pachyphyllum
 * †Pachyphyllum crassicostatum
 * †Pachyphyllum dumonti – type locality for species
 * †Pachyphyllum gregarium
 * †Pachyphyllum minutissimum
 * †Pachyphyllum websteri
 * †Pachyphyllum woodmani
 * †Paladin
 * †Paladin wilsoni
 * †Palaeocapulus
 * †Palaeocapulus equilateralis
 * †Palaeoconcha
 * †Palaeocyclus
 * †Palaeoneilo
 * †Palaeoneilo barrisi
 * †Palaeoneilo fecunda
 * †Palaeostachys
 * †Palaeostachys andrewsii
 * †Palaeozygopleura
 * †Palaeozygopleura difficile
 * †Palmatolepis
 * †Palmatolepis foliacea
 * †Palmatolepis semichatovae
 * †Panderous
 * †Panderous gracilis
 * †Panderous panderi
 * †Parabolbina
 * †Parabolbina antecedans
 * †Parabolbina carinifera
 * †Parabolbina staufferi
 * †Paracosmetocrinus
 * †Paracyclas
 * †Paracyclas dubia
 * †Paracyclas dubius
 * †Paracyclas elliptica
 * †Paracyclas parvula
 * †Paracyclas paucipleura
 * †Paracyclas proavia
 * †Paracyclas sabini
 * †Paracyclas validalinea
 * †Paracyclas validelinea
 * †Paraphorhynchus
 * †Paraphorhynchus elongatum
 * †Paraphorhynchus striatocostatum
 * †Paraschmidtella
 * †Paraschmidtella irregularis
 * †Paraschmidtella uphami
 * †Parenthatia
 * †Parenthatia camerata
 * †Parenthatia punctata
 * †Patellilabia
 * †Patellilabia scriptiferus
 * †Paucicrura
 * †Paucicrura corpulenta
 * †Paupospira
 * Peachocaris strongi.jpg †[[Peachocaris]]
 * †Peachocaris acanthouraea – type locality for species
 * †Pedomphalella
 * †Pedomphalella intermedia
 * †Pedomphalella subovata
 * †Pentamerella
 * †Pentamerella dubia
 * †Pentamerella laeviscula
 * †Pentamerella laeviuscula
 * †Pentamerella magna
 * †Pentamerella multicostella
 * †Pentamerella obsolescens
 * †Pentamerella rugosa
 * †Pentamerella subarata
 * †Pentameroides
 * †Pentameroides corrugatus
 * †Pentameroides subrectus
 * PentamerusSilurian.jpg †[[Pentamerus]]
 * †Pentamerus oblongus
 * †Pentlandina
 * †Pentremites
 * †Pentremites pulchellus
 * †Perditocardinia
 * †Perditocardinia iowensis – type locality for species
 * †Periechocrinus
 * †Pernopecten
 * †Pernopecten cooperensis
 * †Petalocrinus
 * †Petalocrinus mirabilis
 * Petalodus ohioensis fossil.jpg †[[Petalodus]]
 * †Petalodus allegheniensis
 * †Petalotrypa
 * †Petalotrypa formosa
 * †Petrocrania
 * †Petrocrania famelica
 * †Petrocrania familica
 * †Petrodus
 * †Petrodus patelliformis
 * †Phacops
 * †Phacops iowensis
 * †Phanerotrema
 * †Philhedra
 * †Philhedra sheldoni
 * †Phillipsia
 * †Phoebodus
 * †Phoebodus densneptuni – type locality for species
 * †Pholidostrophia
 * †Pholidostrophia iowensis
 * †Phragmoceras
 * †Phragmodus
 * †Phragmodus cognitus
 * †Phragmodus undatus
 * †Phricodothyris
 * †Phymatopleura
 * †Physonemus
 * †Physonemus hamuspiscatorius
 * †Physonemus pandatus
 * †Piloricilla
 * †Piloricilla sedaliensis
 * †Pinnocaris
 * †Pinnocaris americana – type locality for species
 * †Pisocrinus
 * Plaesiomyiidae - Plesiomys subquadrata.JPG †[[Plaesiomys]]
 * †Plaesiomys subquadrata
 * †Plagioglypta
 * †Plagioglypta iowaensis
 * †Planalvus – type locality for genus
 * †Planalvus gibberosa – type locality for species
 * †Plasmopora
 * †Platyceras
 * †Platyceras antiquum
 * †Platyceras insolitum
 * †Platyceras irrasum
 * †Platyceras latum – tentative report
 * †Platyceras nasutum
 * †Platyceras paralium
 * Platycrinitidae - Platycrinites hemisphaericus cropped.jpg †[[Platycrinites]]
 * †Platycrinus
 * †Platylichas
 * †Platyrachella
 * †Platyrachella ballardi
 * †Platyrachella macbridei
 * †Platyschisma
 * †Platyschisma barrisi
 * †Platyschisma depressa
 * †Platyschisma laudoni – type locality for species
 * †Platystrophia
 * †Platystrophia biforata
 * †Plectatrypa
 * †Plectodina
 * †Plectodina aculeata
 * †Plectodonta
 * †Plectodonta produla
 * Pleurocystites squamosus.jpg †[[Pleurocystites]]
 * †Pleurocystites beckeri
 * †Pleurocystites filitextus – tentative report
 * †Pleurocystites strimplei
 * Pleurotomaria – tentative report
 * †Pleurotomaria verticillata
 * †Plicochonetes
 * †Plicostricklandia
 * †Podolithus
 * †Poleumita
 * †Polusocrinus
 * †Polusocrinus rosa
 * Polygnathus Pa elements.png †[[Polygnathus]]
 * †Polygnathus decorosus
 * †Polygnathus intermedius
 * †Polygnathus parawebbi
 * †Polygnathus xylus
 * †Polyplacognathus
 * †Polyplacognathus ramosus
 * †Polytryphocycloides
 * †Polytylites
 * †Polytylites wilsoni
 * †Porcellia
 * †Porcellia crassinoda
 * †Porcellia obliquinoda
 * †Porcellia rectinoda – type locality for species
 * †Porocrinus
 * †Porocrinus crassus
 * †Porocrinus fayettensis
 * †Porocrinus pentagonius
 * †Porpites
 * †Posidonia
 * †Praecupulocrinus
 * †Praecupulocrinus conjugans
 * †Praenucula – tentative report
 * †Praewaagenoconcha
 * †Praewaagenoconcha speciosa
 * †Prasopora
 * †Prasoporina
 * †Pregazacrinus
 * †Pregazacrinus hemisphericus
 * †Primitia
 * †Primitia gibbera
 * †Primitia spinata
 * †Primitiella
 * †Primitiella bellevuensis
 * †Primitiella carlei
 * †Primitiella constricta
 * †Primitiella milleri
 * †Primitiella plattevillensis
 * †Primitiopsis – tentative report
 * †Primitiopsis bella
 * †Primitopsis – tentative report
 * †Primitopsis bella
 * †Priscella
 * †Probillingsites
 * †Productella
 * †Productella belanskii
 * †Productella camerata
 * †Productella fragilis
 * †Productella iowa
 * †Productella linnensis
 * †Productella perplana
 * †Productella rugatula
 * †Productella sericea
 * †Productella subaculeata
 * †Productella subalata
 * †Productella thomasi
 * †Productus
 * †Productus arcuatus
 * †Productus ovatus
 * †Productus sedaliensis
 * †Proetides
 * †Proetides insignis
 * Proetus concinnus reconstruction cropped.png †[[Proetus (trilobite)|Proetus]]
 * †Proetus channahonensis – or unidentified comparable form
 * †Promexyele
 * †Promexyele peyeri
 * †Prospira
 * †Prospira greenockensis – or unidentified related form
 * †Prospira legrandensis
 * †Protacrocrinus
 * †Protatrypa
 * †Protaxocrinus
 * †Protoleptostrophia
 * †Protoleptostrophia fragilis
 * †Protomegastrophia
 * †Protometgastrophia
 * †Protoniella
 * †Protoniella parva
 * †Protoscolex
 * †Pseudoammodiscus
 * †Pseudoatrypa
 * †Pseudoatrypa bentonensis
 * †Pseudoatrypa blackhawkensis
 * †Pseudoatrypa boyeri – or unidentified comparable form
 * †Pseudoatrypa bremerensis
 * †Pseudoatrypa devoniana
 * †Pseudoatrypa minor
 * †Pseudoatrypa percrassa
 * †Pseudoatrypa rotunda
 * †Pseudoatrypa rugatula
 * †Pseudobelodina – tentative report
 * †Pseudoconocardium
 * †Pseudoglomospira
 * †Pseudopalmula
 * †Pseudopalmula palmuloides
 * †Pseudoplagiothyra
 * †Pseudoplagiothyra praecursor
 * †Pseudozygopleura
 * †Pseudulrichia
 * †Pseudulrichia simplex
 * †Pterinea
 * †Ptychophyllum
 * †Ptychopleurella
 * †Ptychopleurella bouchardi – or unidentified comparable form
 * †Ptychopteria
 * †Ptychopteria chemungensis
 * †Ptyctodopsis – type locality for genus
 * †Ptyctodopsis menzeli – type locality for species
 * Ptyctodus compressus cropped.jpg †[[Ptyctodus]]
 * †Pugnoides
 * †Pugnoides calvini
 * †Pugnoides ottumwa
 * †Punctaparchites
 * †Punctaparchites rugosus
 * †Punctaparchites splendens
 * †Punctospirifer
 * †Punctospirifer solidirostris
 * †Pycnostylus
 * †Pyramiblastus
 * †Pyramiblastus fusiformis – type locality for species
 * †Pyrgocystis

Q

 * †Quasibollia
 * †Quasibollia ridicula
 * †Quienquecaudex
 * †Quienquecaudex springeri

R



 * †Raphistomina
 * †Raymondatia
 * †Raymondatia goniglypta
 * †Raymondatia gonigplyta
 * †Raymondiata
 * †Raymondiata goniglypta
 * †Resserella
 * †Retichonetes
 * †Retichonetes brandonensis
 * †Reticularia
 * †Reticularia cooperensis
 * †Retispira
 * †Retispira bilabiatus
 * †Retispira deflectus
 * †Retispira exilis
 * †Retispira perelegans
 * †Retispira type locality for species Kues & Batten 2001 – informal
 * †Rhaphanocrinus
 * †Rhaphistomina
 * †Rhineoderma
 * †Rhineoderma dinglensis
 * †Rhipidium
 * †Rhipidomella
 * †Rhipidomella cuneata
 * †Rhipidomella dalyana – or unidentified comparable form
 * †Rhipidomella tenuicostata
 * †Rhipidomella thiemei
 * †Rhodocrinites
 * †Rhombopora
 * †Rhynchodus
 * †Rhynchopora
 * †Rhynchopora pustulosa
 * †Rhynchopora rowleyi
 * †Rhynchotrema
 * †Rhynchotreta
 * †Rhyssochonetes
 * †Rhyssochonetes bellarugosis
 * †Rigidella
 * †Ripidiorhynchus
 * †Ripidiorhynchus cedarensis
 * †Rugosochonetes
 * †Rugosochonetes multicastatus

S

 * †Saccelatia
 * †Saccelatia angularis
 * †Saccelatia arcuamuralis
 * †Saccelatia arrecta
 * †Saccelatia bullata
 * †Saccelatia cletifera
 * †Sanguinolites
 * †Scaphelasma
 * †Schellwienella
 * †Schellwienella crenulicostata
 * †Schellwienella inaequalis
 * †Schellwienella inflata
 * †Schellwienella planumbona
 * †Schizoblastus
 * †Schizoblastus roemeri
 * †Schizodus
 * †Schizodus sedaliensis
 * †Schizodus trigonalis
 * †Schizophoria
 * †Schizophoria amanaensis
 * †Schizophoria athabaskensis – or unidentified related form
 * †Schizophoria athabaskiensis – or unidentified related form
 * †Schizophoria chouteauensis
 * †Schizophoria dorsata
 * †Schizophoria floydensis
 * †Schizophoria floydia
 * †Schizophoria impressa
 * †Schizophoria iowensis
 * †Schizophoria landoni
 * †Schizophoria lata
 * †Schizophoria laudoni
 * †Schizophoria macfarlanei
 * †Schizophoria macfarlanii
 * †Schizophoria minor
 * †Schizophoria multistriata
 * †Schizophoria subelliptica
 * †Schmidtella
 * †Schmidtella affinis
 * †Schmidtella brevis
 * †Schmidtella lacunosa
 * †Schmidtella latimarginata
 * †Schuchertella
 * †Schuchertella acutistriata
 * †Schuchertella altirostris
 * †Schuchertella humboldtensis
 * †Schuchertella iowensis
 * †Schuchertella nodocostata
 * †Schuchertella parva
 * †Schuchertella pectiniformis
 * †Scofielda
 * †Scofielda bilateralis
 * †Scofieldia
 * †Scofieldia bilateralis
 * †Scutellum
 * †Scutellum depressum
 * †Scutellum thomasi
 * Scytalocrinidae - Scytalocrinus.JPG †[[Scytalocrinus]]
 * †Selenella
 * †Selenella pediculus
 * †Semitextularia
 * †Semitextularia thomasi
 * †Septemchiton
 * †Septemchiton iowaensis
 * †Septemchiton iowensis
 * †Septopora
 * †Serpulospira
 * †Serpulospira paradoxus – type locality for species
 * †Setigerites
 * †Shumardella
 * †Sieberella – tentative report
 * †Sieberella insolita
 * †Sievertsia
 * †Sigournea – type locality for genus
 * †Sigournea multidentata – type locality for species
 * †Similodonta
 * †Similodonta obliqua
 * †Simulodonta
 * †Simulodonta obliqua
 * †Sinuites
 * †Sinuites subcompressa
 * †Siphonocrinus
 * †Siphonocrinus nobilis
 * †Skenidioides – tentative report
 * †Skenidium
 * †Skenidium independense
 * †Smithiphyllum
 * †Smithiphyllum belanskii
 * †Sowerbyella
 * †Spathella
 * †Sphaerirhynchia
 * SphenothallidHoldfastOrdovician.jpg †[[Sphenothallus]]
 * †Spinatrypa
 * †Spinatrypa aspera
 * †Spinatrypa augusticostata – or unidentified comparable form
 * †Spinatrypa bellula
 * †Spinatrypa borealis
 * †Spinatrypa hystrix
 * †Spinatrypa mascula
 * †Spinatrypa occidentalis
 * †Spinatrypa planosulcata
 * †Spinatrypa rockfordensis
 * †Spinatrypa trulla
 * †Spinatrypina
 * †Spinatrypina angusticostata – or unidentified comparable form
 * †Spinatrypina edmundsi
 * †Spinocarinifera
 * †Spinocarinifera arcuata
 * †Spinocarinifera arcuatus
 * †Spinocyrtia
 * †Spinocyrtia alta
 * †Spinocyrtia ballardi
 * †Spinocyrtia capax
 * †Spinocyrtia cedarensis
 * †Spinocyrtia corvirostra
 * †Spinocyrtia curvirostra
 * †Spinocyrtia cyrtiformis
 * †Spinocyrtia cyrtinaformis
 * †Spinocyrtia iowensis
 * †Spinocyrtia macbridei
 * †Spinocyrtia pulchra
 * †Spinocyrtia westerensis
 * †Spinulicosta
 * †Spinulicosta spinulicosta
 * Spirifer perlamosus pedunculate valve.jpg †[[Spirifer]]
 * †Spirifer biplicoides
 * †Spirifer forbesi
 * †Spirifer gregeri
 * †Spirifer legrandensis
 * †Spirifer louisianensis
 * †Spirifer marshallensis
 * †Spirifer missouriensis
 * †Spirifer orestes
 * †Spirifer platynotus
 * †Spirifer stratiformis
 * †Spiriferina
 * †Spiriferina solidirostris
 * †Spiriferina solidirostrus
 * †Spiriferina subtexta
 * †Spirinella
 * Spirorbis
 * †Spyroceras
 * †Stachyodes
 * †Stachyodes costulata
 * †Stainbrookia
 * †Stainbrookia infera
 * †Staufferella
 * †Staufferella falcata
 * †Stegocoelia
 * †Stegocoelia quadricincta – type locality for species
 * †Stenopareia
 * †Stenopareia slocomi – or unidentified comparable form
 * †Stenopareiea
 * †Stephanocrinus
 * †Stereostylus
 * †Stereostylus aages – type locality for species
 * Steth pair1 cropped.jpg †[[Stethacanthus]]
 * †Stethacanthus depressus
 * †Stethacanthus erectus
 * †Stictopora
 * †Stictostroma
 * †Stictostroma ordinarium
 * †Straparollus
 * †Straparollus ammon
 * †Straparollus argutus – type locality for species
 * †Straparollus cyclostomus
 * †Straparollus macromphalus
 * †Streptelasma
 * †Streptelasma trilobatum – or unidentified comparable form
 * †Streptis
 * †Streptognathodus
 * †Streptognathodus delicatulus – type locality for species
 * †Streptognathodus symmetricus – type locality for species
 * †Streptorhynchus
 * †Streptorhynchus tenuicostatum
 * †Striatochonetes
 * †Striatochonetes buchananensis
 * †Striatochonetes schucherti
 * †Striatopora
 * †Striatopora iowensis
 * †Stricklandia
 * †Stricklandia laevis
 * †Stricklandia lens
 * †Striispirifer
 * †Strimplecrinus
 * †Strobilocystites
 * †Stromatopora
 * †Strophalosia
 * †Strophodonta
 * †Strophodonta umbonata
 * †Stropholosia
 * †Stropholosia littletonensis
 * Strophomena costellata brachial.jpg †[[Strophomena]]
 * †Strophomena abnormalis
 * †Strophomena biplacata
 * †Strophomena cedarensis
 * †Strophomena cicatricosa
 * †Strophomena costata
 * †Strophomena dorsata
 * †Strophomena erratica
 * †Strophomena halli
 * †Strophomena iowensis
 * †Strophomena linderi
 * †Strophomena littleonensis
 * †Strophomena littletonensis
 * †Strophomena masonensis
 * †Strophomena mineolaensis
 * †Strophomena nortoni
 * †Strophomena parva
 * †Strophomena perarcuata
 * †Strophomena planodorsata
 * †Strophomena plicata
 * †Strophomena quadratella
 * †Strophomena randalia
 * †Strophomena reticulata
 * †Strophomena scottensis
 * †Strophomena solonensis
 * †Strophomena subdemissa
 * †Strophomena thomasi
 * †Strophomena trilobata – type locality for species
 * †Strophomena unbonata
 * †Strophomena vera
 * †Strophonella
 * †Strophonelloides
 * †Strophonelloides reversa
 * †Strophostylus
 * †Strophostylus bivolve
 * †Stylonema – tentative report
 * †Sublobalocrinus
 * †Sublobalocrinus kasseri
 * †Sulcatostrophia
 * †Sulcatostrophia camerata
 * †Sulcatostrophia euglyphea
 * †Sygcaulocrinus
 * †Sygcaulocrinus typus
 * Syringoporid.jpg †[[Syringopora]]
 * †Syringostroma – tentative report
 * †Syringostroma confertum
 * †Syringothyris
 * †Syringothyris halli
 * †Syringothyris hannibalensis
 * †Syringothyris newarkensis

T

 * †Tabulophyllum
 * †Tabulophyllum buccinum – type locality for species
 * †Tabulophyllum curtum – type locality for species
 * †Tabulophyllum ehlersi
 * †Tabulophyllum ellipticum
 * †Tabulophyllum expansum
 * †Tabulophyllum levorsoni – type locality for species
 * †Tabulophyllum longum
 * †Tabulophyllum magnum
 * †Tabulophyllum mutabile – type locality for species
 * †Tabulophyllum ponderosum
 * †Tabulophyllum rectum
 * †Tabulophyllum robustum
 * †Tabulophyllum rotundum
 * †Tabulophyllum solidum
 * †Tanaocystis
 * †Tanaocystis type locality for species – informal
 * †Tarphyphyllum
 * †Tarphyphyllum cylindricum – type locality for species
 * Taxocrinidae - Taxocrinus.JPG †[[Taxocrinus]]
 * †Tecnocyrtina
 * †Tecnocyrtina curvilineata
 * †Tecnocyrtina missouriensis
 * †Tenticospirifer
 * †Tenticospirifer cyrtinaeformis
 * †Tenticospirifer cyrtinaformis
 * †Tenticospirifer shellrockensis
 * †Tetradella
 * †Tetradella carinata
 * †Tetradella ellipsilira
 * †Tetradella septinoda
 * †Tetradella subquadrans
 * †Tetradella ulrichi
 * †Teutonophon
 * †Teutonophon tangentialis
 * †Thaerodonta
 * †Thaerodonta recedens
 * †Thalamocrinus
 * †Theleproktocrinus
 * †Theleproktocrinus davidsoni
 * †Theodissa
 * †Theodissa hungerfordi
 * †Theodossia
 * †Theodossia hungerfordi
 * †Thomasaria
 * †Thomasaria altumbona
 * †Thomasatia
 * †Thomasatia falcicosta
 * †Thomasocrinus
 * †Thomasocrinus cylindrica
 * †Timeischytes
 * †Torynifer
 * †Trachydomia
 * †Trachydomia variata
 * †Tranodis
 * †Trapezophyllum
 * †Tremanotus
 * †Trichinocrinus
 * †Trigeria
 * †Trimerella
 * †Triplesia
 * †Trochonema
 * †Tropidodiscus
 * †Trupetustroma
 * †Trupetustroma bassleri
 * †Trupetustroma hayense
 * †Tubisalebra
 * †Turbonopsis
 * †Turbonopsis hackberryensis
 * †Turbonopsis spiculatus – type locality for species
 * †Tylothyris
 * †Tylothyris bimesialis
 * †Tylothyris inultilis
 * †Tylothyris megista
 * †Tylothyris mesacostalis
 * †Tylothyris rockfordensis
 * †Tylothyris subattenuatta
 * †Tylothyris subvaricosa
 * †Tylothyris sulcocostata

U

 * †Ulocrinus
 * †Ulrichia
 * †Ulrichia saccula
 * †Unispirifer
 * †Unispirifer minnewankensis – or unidentified comparable form
 * †Unispirifer platynotus

V

 * †Variatrypa
 * †Variatrypa arctica
 * †Variatrypa lineata
 * †Variatrypa rugatula
 * †Verkhotomia – tentative report
 * †Verkhotomia calvini

W

 * †Waagenella
 * †Waagenella sowerbyi – tentative report
 * †Warrenella
 * †Warrenella extensa
 * †Warthia
 * †Wellerella
 * †Westerna
 * †Westerna gigantea
 * †Whatcheeria – type locality for genus
 * †Whatcheeria deltae – type locality for species
 * †Whidbornella
 * †Whidbornella lachrymosa
 * †Whitfieldella
 * †Winchellatia
 * †Winchellatia lansingensis
 * †Winchellatia longispina
 * †Winchellatia minnesotensis
 * †Worthenia

Y

 * †Youngia

Z

 * †Zaphrenthis
 * †Zaphrenthis calceola
 * †Zaphrenthis cliffordana
 * †Zygobolboides
 * †Zygobolboides calvini
 * †Zygobolboides grafensis
 * †Zygobolboides iowensis
 * †Zygobolboides thomasi
 * †Zygospira
 * †Zygospira resupinata