Opinions from E. D. Cope 1873
- 'Aceratherium megalodum is recombined as Aphelops megalodus'
- 'Aciprion formosum belongs to Aciprion'
- 'Aphelophis talpivorus belongs to Aphelophis'
- 'Bunaelurus lagophagus belongs to Bunaelurus'
- 'Calamagras angulatus belongs to Calamagras'
- 'Calamagras murivorus belongs to Calamagras'
- 'Calamagras truxalis belongs to Calamagras'
- 'Canis hartshornianus belongs to Canis'
- 'Canis lippincottianus belongs to Canis'
- 'Canis osorum belongs to Canis'
- 'Cremastosaurus carinicollis belongs to Cremastosaurus'
- 'Daptophilus squalidens belongs to Daptophilus'
- 'Diacium quinquepedalis belongs to Diacium'
- 'Diacium unipedalis belongs to Diacium'
- 'Embassis alternans belongs to Embassis'
- 'Exostinus serratus belongs to Exostinus'
- 'Gymnoptychus chrysodon is recombined as Ischyromys chrysodon'
- 'Heliscomys vetus belongs to Heliscomys'
- 'Herpetotherium fuzax is corrected as Herpetotherium fugax and belongs to Herpetotherium'
- 'Herpetotherium huntii belongs to Herpetotherium'
- 'Herpetotherium marginale belongs to Herpetotherium'
- 'Herpetotherium scalare belongs to Herpetotherium'
- 'Herpetotherium stevensonii belongs to Herpetotherium'
- 'Herpetotherium tricuspis belongs to Herpetotherium'
- 'Hypisodus ringens belongs to Hypisodus'
- 'Hyracodon arcidens belongs to Hyracodon'
- 'Isacis caniculus belongs to Isacis'
- 'Leptauchenia calcarata belongs to Leptauchenia'
- 'Leptauchenia minima is recombined as Hypisodus minimus'
- 'Machaerodus oreodontis belongs to Machaerodus'
- 'Mastodon proavus belongs to Mastodon'
- 'Megaceratops acer is recombined as Symborodon acer'
- 'Megaceratops helocerus is recombined as Symborodon heloceras'
- 'Miobasileus ophryas belongs to Miobasileus'
- 'Miothen crassigenis belongs to Miothen'
- 'Miothen gracile belongs to Miothen'
- 'Neurodromicus belongs to Ophidia'
- 'Neurodromicus dorsalis belongs to Neurodromicus'
- 'Palaeolagus agapetillus is recombined as Tricium agapetilla'
- 'Palaeotherium bairdii is recombined as Anchitherium bairdii'
- 'Paramys relictus belongs to Paramys'
- 'Peltosaurus granulosus belongs to Peltosaurus'
- 'Platyrhachis coloradoensis belongs to Platyrhachis'
- 'Rhinoceros nebraskensis is recombined as Hyracodon nebrascensis'
- 'Rhinoceros occidentalis is recombined as Aceratherium occidentale'
- 'Symborodon altirostris belongs to Symborodon'
- 'Symborodon bucco belongs to Symborodon'
- 'Symborodon torvus belongs to Symborodon'
- 'Symborodon trigonoceras belongs to Symborodon'
- 'Testudo amphithorax belongs to Testudo'
- 'Testudo culbratus [misspelled as Testudo cultratus] belongs to Testudo'
- 'Testudo laticuneus belongs to Testudo'
- 'Testudo ligonius belongs to Testudo'
- 'Tricium annae belongs to Tricium'