- A
- B
- C
- D
- E
- F
- G
- H
- I
- J
- K
- L
- M
- N
- O
- P
- R
- S
- T
- V
- W
- X
- Z
- References
This list of the Mesozoic life of Colorado contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of Colorado and are between 252.17 and 66 million years of age. A{{Compact ToC}}- †Acanthichnus – tentative report
- Acila
- Acmaea
- †Acmaea genettae – type locality for species
- †Adocus
- †Albanerpeton
- †Albertosaurus – tentative report
- †Aletridelphys
- †Allantodiopsis
- †Allantodiopsis erosa
- †Allantodiopsis JC018 – informal
- †Allosaurus – type locality for genus
- †Allosaurus fragilis – type locality for species
- †Allosaurus lucasi – type locality for species
- †Amblotherium – type locality for genus
- Amia
- †Amphicoelias – type locality for genus
- †Amphicoelias altus – type locality for species
- †Amphicotylus
- †Amphicotylus lucasii – type locality for species
- †Amplovalvata
- †Anaklinoceras
- †Anaklinoceras minutum – type locality for species
- †Anaklinoceras reflexum
- †Anisoceras
- †Anisomyon
- †Anomia
- †Anomia subquadrata
- †Anomia tellinoides
- †Anomoepus – tentative report
- †Apateodus
- †Apatopus
- †Apatosaurus – type locality for genus
- †Apatosaurus ajax – type locality for species
- †Apatosaurus louisae – type locality for species
- †Arcellites
- †Archaeolamna
- †Archaeolamna kopingensis
- †Arenicolites
- Aspideretes
- †Aspideretes vagans – type locality for species
- †Aspideretoides
- Astarte
- †Atlantosaurus
- †Atlantosaurus immanis – type locality for species
- †Axonoceras
B{{Compact ToC}}- †Baculites
- †Baculites aquilaensis
- †Baculites asper
- †Baculites clinolobatus – type locality for species
- †Baculites codyensis
- †Baculites compressus
- †Baculites cuneatus
- †Baculites grandis
- †Baculites haresi
- †Baculites mclearni
- †Baculites meeki – type locality for species
- †Baculites reesidei
- †Barosaurus
- †Basilemys
- †Basilemys sinuosa – or unidentified comparable form
- †Behuninia
- †Bellifusus
- †Bison
- †Bison alticornis – type locality for species
- †Borealosuchus
- †Borealosuchus sternbergii
- {{multiple image
| total_width = 330 | image1 = Brachauchenius lucasi2DB.jpg | alt1 = | image2 = Brachiosaurus scale.png | alt2 = | image3 = Brontosaurus NT small.jpg | alt3 = | footer = Left: Life restoration of the Late Cretaceous plesiosaur Brachauchenius hunting a hesperornithiform bird. Middle: Diagram illustrating the Late Jurassic sauropod dinosaur Brachiosaurus with an anachronistic human to scale. Right: Life restoration of a herd of the Late Jurassic sauropod dinosaur Brontosaurus.}} †Brachauchenius – or unidentified comparable form - †Brachiosaurus – type locality for genus
- †Brachiosaurus altithorax – type locality for species
- †Brachychampsa
- †Brachychirotherium
- †Brachyphyllum
- †Brachyphyllum rechtenii – type locality for species
- †Brontosaurus
- †Brontosaurus excelsus
- †Brontosaurus yahnahpin
C{{Compact ToC}}- †Calycoceras
- †Calycoceras canitaurinum
- †Calycoceras naviculare
- {{multiple image
| total_width = 248 | image1 = Camarasaurs1.jpg | alt1 = | image2 = Camptosaurus.jpg | alt2 = | footer = Left: Life restoration of a herd of the Late Jurassic sauropod dinosaur Camarasaurus. Right: Life restoration of the Late Jurassic ornithopod dinosaur Camptosaurus.}} †Camarasaurus – type locality for genus - †Camarasaurus agilis – type locality for species
- †Camarasaurus grandis
- †Camarasaurus lewisi
- †Camarasaurus supremus – type locality for species
- †Camptosaurus – type locality for genus
- †Camptosaurus dispar – type locality for species
- Carcharias
- †Carcharias amonensis
- †Carcharias saskatchewanensis
- †Carcharias tenuiplicatus
- †Caririchnium
- †Caririchnium leonardii – type locality for species
- †Caririchnium leonaridii
- †Cataceramus
- †Cataceramus gladbeckensis
- †Cedrobaena
- †Ceratodus – type locality for genus
- †Ceratodus felchi – type locality for species
- †Ceratodus guentheri – type locality for species
- †Ceratosaurus – type locality for genus
- †Ceratosaurus nasicornis – type locality for species
- Cerithiopsis
- †Champsosaurus
- Chara
- †Chelonipus
- †Chinlea
- †Chinlestegophis – type locality for genus
- †Chinlestegophis jenkinsi – type locality for species
- †Chirotherium
- †Cimolichthys
- †Cimolodon – or unidentified comparable form
- †Cimolomys
- †Cionichthys
- †Cionodon – type locality for genus
- †Cionodon arctatus – type locality for species
- †Cirroceras
- †Cladoceramus
- †Cladoceramus undulatoplicatus
- †Clidastes
- †Clioscaphites
- †Clioscaphites choteauensis
- †Clioscaphites saxitonianus
- †Clioscaphites vermiformis
- †Coahuilites
- †Cochlichnus
- †Codellaster – type locality for genus
- †Codellaster keepersae – type locality for species
- †Coelophysis – tentative report
- †Coelurus
- †Compsemys
- †Coniasaurus
- Corbula
- †Corydalites – type locality for genus
- †Corydalites fecundum – type locality for species
- Crassatella
- †Cremnoceramus
- †Crenella
- †Creonella
- †Cretodus
- †Cretolamna
- †Cretolamna appendiculata
- †Cretomanta
- †Cretoxyrhina
- Cucullaea
- Cuspidaria
- †Czekanowskia
- †Czekanowskia turneri – tentative report
D{{Compact ToC}}- †Diablophis
- †Diablophis gilmorei – type locality for species
- †Didymoceras
- †Didymoceras aurarium – type locality for species
- †Didymoceras cheyennense
- †Didymoceras draconis
- †Didymoceras stevensoni
- †Dinehichnus
- †Dinochelys
- †Diplodocus – type locality for genus
- †Diplodocus lacustris – type locality for species
- †Diplodocus longus – type locality for species
- Diplodonta
- †Diplosaurus
- †Diplosaurus felix – type locality for species
- Discinisca
- †Discoscaphites
- †Docodon
- †Docodon apoxys – type locality for species
- †Dorsetisaurus
- †Dorsetochelys
- †Dorsetochelys buzzops – type locality for species
- †Drepanocheilus
- †Drepanocheilus evansi
- †Drepanocheilus nebrascensis
- †Drepanocheilus obesus
- †Dryophyllum
- †Dryophyllum tennesseensis
- †Dryosaurus
E{{Compact ToC}} | total_width = 248 | image1 = Edmontonia dinosaur.png | alt1 = | image2 = Edmontosaurus regalis.PNG | alt2 = | footer = Left: Life restoration of the Late Cretaceous armored dinosaur Edmontonia. Right: Skeletal reconstruction and restored soft tissue of the Late Cretaceous duck-billed dinosaur Edmontosaurus regalis with an anachronistic human to scale.}} †Edmontonia - †Edmontosaurus
- †Edmontosaurus regalis – type locality for species
- Eilenodon – type locality for genus
- †Eilenodon robustus – type locality for species
- †Elopopsis
- †Enchodus
- †Enchodus gladiolus – or unidentified comparable form
- †Enchodus shumardi – or unidentified comparable form
- †Entolium
- †Eoacteon
- †Eomunidopsis
- †Eomunidopsis cobbani – type locality for species
- †Eosauropus
- †Eosauropus cimarronensis
- †Eosauropus cimmaronensis
- †Equisetum
- †Equisetum burchardtii – or unidentified comparable form
- †Etea
- †Eubrontes
- †Eucalycoceras
- †Eucalycoceras pentagonum
- †Euomphaloceras
- †Euomphaloceras septemseriatum
- †Eutrephoceras
- †Eutretauranosuchus – type locality for genus
- †Eutretauranosuchus delfsi – type locality for species
- †Exiteloceras
- †Exogyra
- †Exogyra boveyensis – or unidentified related form
F{{Compact ToC}}- †Fagesia
- Ficus
- †Forresteria
- †Forresteria hobsoni – type locality for species
- †Fruitachampsa – type locality for genus
- †Fruitachampsa callisoni – type locality for species
- †Fruitadens – type locality for genus
- †Fruitadens haagarorum – type locality for species
- †Fruitafossor – type locality for genus
- †Fruitafossor windscheffeli – type locality for species
G{{Compact ToC}}- †Galeamopus
- †Glirodon
- †Glyptops
- †Glyptops plicatulus – type locality for species
- †Goniopholis
- †Goniopholis felchi – type locality for species
- †Grallator
- †Grallator cursorius
- †Grallator tenuis
- †Gryphaeostrea
- †Gwyneddichnium
- †Gypsonictops
- †Gyroides
H{{Compact ToC}} | total_width = 248 | image1 = Hallopus NT.jpg | alt1 = | image2 = Haplocanthosaurus.jpg | alt2 = | footer = Left: Life restoration of the Late Jurassic crocodile relative Hallopus. Right: Life restoration of the Late Jurassic sauropod dinosaur Haplocanthosaurus.}} †Hallopus - †Hallopus victor – type locality for species
- †Haplocanthosaurus – type locality for genus
- †Haplocanthosaurus delfsi – type locality for species
- †Haplocanthosaurus priscus – type locality for species
- †Harduinia
- †Harduinia stantoni
- †Harduinia taylori
- †Haresiceras
- †Haresiceras placentiforme
- †Helopanoplia
- †Helopanoplia distincta – or unidentified comparable form
- †Hemicalypterus
- †Hermanophyton
- †Herrickiceras
- †Holaster
- †Holaster feralis – type locality for species
- †Homolopsis
- †Hoploscaphites
- †Hoploscaphites birkelundae
- †Hoploscaphites landesi
- †Hoploscaphites nicolletii
- †Hulettia – report made of unidentified related form or using admittedly obsolete nomenclature
- †Hulettia hawesi – type locality for species
- †Hypsirophus – type locality for genus
- †Hypsirophus discurus – type locality for species
I{{Compact ToC}}- †Ichthyodectes
- †Ignotornis – type locality for genus
- †Ignotornis mcconnelli – type locality for species
- †Inoceramus
- †Inoceramus altus
- †Inoceramus altusiformis
- †Inoceramus anomalus
- †Inoceramus arnoldi
- †Inoceramus balticus
- †Inoceramus brancoiformis
- †Inoceramus bueltenensis
- †Inoceramus cordiformis
- †Inoceramus crippsi – or unidentified related form
- †Inoceramus deformis
- †Inoceramus erectus
- †Inoceramus flavus
- †Inoceramus grandis
- †Inoceramus longealatus
- †Inoceramus muelleri - or unidentified loosely related form
- †Inoceramus oblongus
- †Inoceramus pictus
- †Inoceramus prefragilis
- †Inoceramus rutherfordi – or unidentified comparable form
- †Inoceramus tenuistriatus – tentative report
- †Inoceramus tenuistriatus() – tentative report
- †Ischyrhiza
- †Ischyrhiza avonicola – or unidentified comparable form
J{{Compact ToC}}- †Jeletzkytes
- †Jeletzkytes brevis
- †Jeletzkytes dorfi
- †Jeletzkytes nodosus
- †Jensensispermum
- †Jensensispermum redmondii
- Jupiteria
K{{Compact ToC}}- †Kepodactylus – type locality for genus
- †Kepodactylus insperatus – type locality for species
L{{Compact ToC}}- †Laosaurus – report made of unidentified related form or using admittedly obsolete nomenclature
- Laternula
- Lepisosteus – tentative report
- †Lepisosteus occidentalis
- †Leptalestes – tentative report
- †Leptolepis – or unidentified comparable form
- †Lewyites
- Lima
- †Lima janetae – type locality for species
- †Lingula
- †Lioestheria
- †Lioestheria tendagurensis – or unidentified comparable form
- †Lisserpeton
- †Lonchidion
- †Lucina
- †Lyropecten
M{{Compact ToC}}- †Macelognathus
- †Magadiceramus
- †Magadiceramus complicatus
- †Magadiceramus crenelatus
- †Magadiceramus soukupi - or unidentified loosely related form
- †Magadiceramus subquadratus
- †Magnoavipes
- †Magnoavipes caneeri – type locality for species
- †Marmarthia – or unidentified comparable form
- {{multiple image
| total_width = 248 | image1 = Marshosaurus restoration.jpg | alt1 = | image2 = Meniscoessus skull.jpg | alt2 = | footer = Left: Life restoration of the Late Jurassic megalosaur Marshosaurus. Right: Fossilized skull of the Late Cretaceous multituberculate mammal Meniscoessus.}} †Marshosaurus – or unidentified comparable form - †Meniscoessus
- †Meniscoessus collomensis – type locality for species
- †Meniscoessus conquistus
- †Meniscoessus robustus – or unidentified comparable form
- †Mesadactylus – type locality for genus
- †Mesadactylus ornithosphyos – type locality for species
- †Mesembrioxylon
- †Mesembrioxylon carterii – type locality for species
- †Mesodma
- †Mesodma formosa – or unidentified comparable form
- †Mesojassoides – type locality for genus
- †Mesojassoides gigantea – type locality for species
- †Mesolanistes
- †Metengonoceras
- †Metoicoceras
- †Metoicoceras geslinianum
- †Micrabacia
- †Micropycnodon
- †Micropycnodon kansasensis
- †Modiolus
- †Modiolus kremmlingensis – type locality for species
- †Modiolus meeki
- †Moremanoceras
- †Morosaurus
- †Morosaurus laticollis – type locality for species
- †Morrolepis
- †Morrolepis schaefferi – type locality for species
- †Myledaphus
- †Mymoorapelta – type locality for genus
- †Mymoorapelta maysi – type locality for species
- Myrica
- †Mytiloides
- †Mytiloides duplicostatus – or unidentified related form
- †Mytiloides latus – or unidentified comparable form
- †Mytiloides mytiloides
- †Mytiloides opalensis
- †Mytiloides stantoni – or unidentified comparable form
- †Mytiloides submytiloides – or unidentified related form
N{{Compact ToC}}- †Nanosaurus – type locality for genus
- †Nanosaurus agilis – type locality for species
- †Nanosaurus rex
- Natica
- †Nemodon
- †Nemodon adkinsi
- †Nemodon harriesi – type locality for species
- †Neocardioceras
- †Neocardioceras densicostatum – type locality for species
- †Neocardioceras juddii
- †Neocardioceras laevigatum
- †Neocardioceras minutum
- †Neocardioceras uptonense
- †Neocrioceras
- †Neoptychites
- †Neurankylus
- †Nigericeras
- †Nigericeras scotti – type locality for species
- †Nonactaeonina
- †Nonactaeonina deflexa
- †Nonactaeonina triticea
- †Nortedelphys
- †Nostoceras
- †Nostoceras approximans – or unidentified comparable form
- †Nostoceras larimerense – type locality for species
- †Nostoceras monotuberculatum
- †Nostoceras obtusum – or unidentified comparable form
- †Nostoceras splendidum – or unidentified comparable form
- Nucula
- Nuculana
- †Nymphalucina
- †Nymphalucina bourni – type locality for species
- †Nymphalucina cleburni
O{{Compact ToC}}- †Octopodichnus
- †Odaxosaurus
- †Oligoptycha
- †Opertochasma
- †Opisthias
- †Opisthotriton
- †Ornitholestes – tentative report
- †Ornithomimipus
- †Ornithomimipus angustus – or unidentified comparable form
- {{multiple image
| total_width = 248 | image1 = Ornithomimus edmontonicus.jpg | alt1 = | image2 = Othnielosaurus.jpg | alt2 = | footer = Left: Fossilized skeleton of the Late Cretaceouos ostrich dinosaur Ornithomimus. Right: Life restoration of the Late Jurassic ornithischian dinosaur Othnielosaurus.}} †Ornithomimus – type locality for genus - †Ornithomimus velox – type locality for species
- Ostrea
- †Ostrea beloiti
- †Ostrea subradiata
- †Othnielia – tentative report
- †Othnielosaurus
- †Oxybeloceras
- †Oxytoma
P{{Compact ToC}} | total_width = 330 | image1 = Pachycephalosaurus skull.JPG | alt1 = | image2 = Pycnodontidae - Palaeobalistum goedeli.JPG | alt2 = | image3 = Dinosaur tracks in Courtedoux, Switzerland 04.jpg | alt3 = | footer = Left: Fossilized skull of the Late Cretaceous dome-headed dinosaur Pachycephalosaurus. Middle: Fossilized skeleton of the Early Cretaceous-Eocene bony fish Palaeobalistum. Right: Fossils of the sauropod dinosaur ichnogenus Parabrontopodus.}} †Pachycephalosaurus - †Pachyrhizodus
- †Palaeobalistum
- †Palaeopteryx – type locality for genus
- †Paleonelumbo
- †Parabrontopodus – type locality for genus
- †Parabrontopodus mcintoshi – type locality for species
- †Parallelodon
- †Paramacellodus
- †Parapleurites
- †Parapleurites morrisonensis – type locality for species
- †Paressonodon – type locality for genus
- †Paressonodon nelsoni – type locality for species
- †Parikimys – type locality for genus
- †Parikimys carpenteri – type locality for species
- †Parviraptor
- †Pentaceratops
- †Pentaceratops sternbergii
- †Pentasauropus
- †Petropteron – type locality for genus
- †Petropteron mirandum – type locality for species
- †Phelopteria
- †Phelopteria linguaeformis
- †Phelopteria ruppii – type locality for species
- †Phlycticrioceras
- †Phlycticrioceras trinodosus
- †Pinna
- †Placenticeras
- †Placenticeras meeki
- †Placenticeras placentum
- †Placenticeras syrtale
- †Plastomenus – tentative report
- †Plastomenus insignis – type locality for species
- †Plastomenus punctulatus – type locality for species
- †Platanites
- †Platyceramus
- †Platyceramus ahsenensis
- †Platyceramus cycloides
- †Platyceramus mantelli - or unidentified loosely related form
- †Platyceramus platinus
- †Platyognathus
- †Plesiobaena
- †Plesiobaena antiqua – or unidentified comparable form
- †Polyonax – type locality for genus
- †Polyonax mortuarius – type locality for species
- †Preprismatoolithus
- †Preprismatoolithus coloradensis
- †Priacodon
- †Priacodon fruitaensis – type locality for species
- †Prionocyclus
- †Probaena
- †Probaena sculpta – type locality for species
- †Prognathodon
- †Prognathodon overtoni
- †Prognathodon stadtmani – type locality for species
- Propeamussium
- †Protalphadon
- †Protexanites
- †Protexanites shoshonensis
- †Protocardia
- †Protocardia barneyi – type locality for species
- †Protocupressinoxylon
- †Protocupressinoxylon medlynii – type locality for species
- †Protosphyraena
- Prunus
- †Pseudaspidoceras
- †Pseudaspidoceras collignoni
- †Pseudobaculites
- †Pseudocalycoceras
- †Pseudocalycoceras angolaense
- †Pseudocalycoceras dentonense
- †Pseudoisurus
- †Pseudoisurus tomosus – or unidentified comparable form
- †Pseudoperna
- †Pseudoperna bentonensis
- †Pseudoperna congesta
- †Pseudoperna inflatum – type locality for species
- †Pseudotetrasauropus – tentative report
- †Pteraichnus
- †Ptychodus
- †Ptychodus anonymus
- †Ptychodus decurrens
- †Ptychodus occidentalis
- †Ptychodus whipplei
- †Puebloites
- Pycnodonte
R{{Compact ToC}}- †Rhaeboceras
- †Rhaeboceras coloradoense – type locality for species
- †Rhaeboceras halli
- †Rhaeboceras subglobosum
- Rhinobatos
- †Rhynchosauroides
- †Rosselia
- †Rotodactylus
S{{Compact ToC}}- †Sabalites
- †Sabalites JC016 – informal
- †Sabalites LA042 – informal
- †Saurillodon
- †Scapherpeton
- †Scaphites
- †Scaphites binneyi
- †Scaphites depressus
- †Scaphites hippocrepis – or unidentified comparable form
- †Scaphites nodosus
- †Schadipes – type locality for genus
- †Schadipes crypticus – type locality for species
- †Sciponoceras
- †Scoyenia
- †Selaginella
- †Selaginella JC023 – informal
- {{multiple image
| total_width = 248 | image1 = Semionotus bergeri.jpg | alt1 = | image2 = Squalicorax falcatusDB.jpg | alt2 = | footer = Left: Fossilized skeleton of the Late Triassic-Early Jurassic bony fish Semionotus. Right: Life restoration of the Late Cretaceous shark Squalicorax.}} †Semionotus - †Solenoceras
- †Solenoceras larimerense
- †Solenoceras reesidei – or unidentified comparable form
- †Solenoceras texanum
- †Sphenodiscus
- †Sphenodiscus pleurisepta
- †Spiroxybeloceras
- †Spiroxybeloceras meekanum
- Squalicorax
- †Squalicorax curvatus
- †Squalicorax falcatus
- †Squalicorax pristodontus
- †Squatirhina
- †Stegosaurus – type locality for genus
- †Stegosaurus armatus – type locality for species
- †Stegosaurus stenops – type locality for species
- †Stegosaurus ungulatus
- †Steinerocaulis
- †Stenomyti – type locality for genus
- †Stenomyti huangae – type locality for species
- †Stokesosaurus – or unidentified comparable form
- †Stramentum
- Sulcoretusa
- †Sulcoretusa dominici – type locality for species
- †Sumitomoceras
- †Sumitomoceras bentonianum
- †Sumitomoceras conlini
- †Supersaurus – type locality for genus
- †Supersaurus vivianae – type locality for species
- †Syncyclonema
- †Synorichthys – type locality for genus
- †Synorichthys stewarti – type locality for species
T{{Compact ToC}}- †Tanaocrossus – type locality for genus
- †Tanaocrossus kalliokoskii – type locality for species
- †Tanocrossus
- Tellina
- †Tenea
- Teredo
- †Texanites
- †Thalassomedon – type locality for genus
- †Thalassomedon hanningtoni – type locality for species
- †Theiophytalia – type locality for genus
- †Theiophytalia kerri – type locality for species
- †Therangospodus – or unidentified comparable form
- †Thescelosaurus
- †Tibiaporrhais
- †Tibiaporrhais cooperensis
- †Titanosaurus
- †Titanosaurus montanus – type locality for species
- †Torosaurus
- †Torvosaurus – type locality for genus
- †Torvosaurus tanneri – type locality for species
- †Trachybaculites
- †Trachybaculites columna – or unidentified comparable form
- †Treptichnus
- †Triceratops
- †Triceratops galeus – type locality for species
- †Triceratops horridus
- †Trinacromerum – or unidentified comparable form
- Trochocyathus
- †Turbinopsis
- Turritella
- †Turseodus
- †Turseodus dolorensis – type locality for species
- {{multiple image
| total_width = 248 | image1 = Tylosaurus-proriger.jpg | alt1 = | image2 = Tyrannosaurus Rex Holotype.jpg | alt2 = | footer = Left: Life restoration of the Late Cretaceous mosasaur Tylosaurus. Right: Mounted fossilized skeleton of the Late Cretaceous tyrannosaur Tyrannosaurus.}} †Tylosaurus V{{Compact ToC}}- †Vanikoropsis
- †Vanikoropsis nebrascensis
- †Vascoceras
- Viviparus
- †Volviceramus
- †Volviceramus grandis
- †Volviceramus involutus
- †Voysa
W{{Compact ToC}}- †Walteria – type locality for genus
- †Walteria jeffersonensis – type locality for species
- †Walteria jeffersoni – type locality for species
- †Watinoceras
- †Watinoceras coloradoense – type locality for species
- †Websteria
- †Worthoceras
X{{Compact ToC}}- †Xenoxylon
- †Xenoxylon moorei – type locality for species
- †Xiphactinus
Z{{Compact ToC}}- †Zyziphus
- †Zyziphus fibrillosus
- †Zyziphus LA007 – informal
- †Zyziphus LA032 – informal
References- {{cite web |title=Fossilworks: Gateway to the Paleobiology Database |author=Various Contributors to the Paleobiology Database |url=http://fossilworks.org/ |accessdate=7 August 2017}}
{{Era nav|title=Lists of the prehistoric life of Colorado|prefix=List of the |suffix= life of Colorado}}{{Lists of the Mesozoic life of the United States}}{{portalbar|Paleontology|Mesozoic|Colorado}} 6 : Geology of Colorado|Lists of prehistoric life in the United States|Natural history of Colorado|Paleontology in Colorado|Mesozoic Colorado|Mesozoic life of North America |