Opinions from E. D. Cope 1875
- 'Adocus lineolatus belongs to Adocus'
- 'Agathaumas milo is a subjective synonym of Hadrosaurus occidentalis'
- 'Agathaumas sylvestris belongs to Agathaumas'
- 'Aublysodon mirandus is a subjective synonym of Aublysodon horridus'
- 'Bryactinus belongs to Holocephali'
- 'Bryactinus amorphus belongs to Bryactinus'
- 'Cinodon arctatus is recombined as Cionodon arctatus'
- 'Cionodon stenopsis belongs to Cionodon'
- 'Clidastes cineriarum belongs to Clidastes'
- 'Clidastes planifrons belongs to Clidastes'
- 'Coelosaurus antiquus belongs to Coelosaurus'
- 'Deinodon horridus is recombined as Aublysodon horridus'
- 'Diphrissa belongs to Holocephali'
- 'Diphrissa latidens belongs to Diphrissa'
- 'Dipristis meirsii is recombined as Ischyodus miersii'
- 'Edestosaurus dispar is recombined as Clidastes dispar'
- 'Edestosaurus stenops is recombined as Clidastes stenops'
- 'Edestosaurus tortor is recombined as Clidastes tortor'
- 'Edestosaurus velox is recombined as Clidastes velox'
- 'Enchodus oxytomus belongs to Enchodus'
- 'Enchodus tetraecus belongs to Enchodus'
- 'Geosaurus mitchilli is recombined as Liodon mitchillii'
- 'Hadrosaurus agilis belongs to Hadrosaurus'
- 'Hadrosaurus cavatus belongs to Hadrosaurus'
- 'Hadrosaurus minor belongs to Hadrosaurus'
- 'Hadrosaurus tripos belongs to Hadrosaurus'
- 'Holcodus acutidens is recombined as Mosasaurus acutidens'
- 'Holcodus coryphaeus is recombined as Platecarpus coryphaeus'
- 'Holcodus tectulus is recombined as Platecarpus tectulus'
- 'Holops pneumaticus belongs to Holops'
- 'Hypsibema crassicauda belongs to Hypsibema'
- 'Ischyodus solidulus belongs to Ischyodus' according to Cope 1869
- 'Ischyodus solidulus is recombined as Diphrissa solidula'
- 'Isotaenia belongs to Holocephali'
- 'Isotaenia neocaesariensis belongs to Isotaenia'
- 'Laelaps aquilunguis belongs to Laelaps'
- 'Laelaps macropus belongs to Laelaps'
- 'Lamna macrorhiza belongs to Lamna'
- 'Lamna mudgei belongs to Lamna'
- 'Leptomylus forfex belongs to Leptomylus'
- 'Lestosaurus felix is recombined as Platecarpus felix'
- 'Lestosaurus gracilis is recombined as Platecarpus gracilis'
- 'Lestosaurus latifrons is recombined as Platecarpus latifrons'
- 'Lestosaurus simus is recombined as Platecarpus simus'
- 'Liodon crassartus is recombined as Platecarpus crassartus'
- 'Liodon curtirostris is recombined as Platecarpus curtirostris'
- 'Liodon dyspelor belongs to Liodon'
- 'Liodon glandiferus is recombined as Platecarpus glandiferus'
- 'Liodon ictericus is recombined as Platecarpus ictericus'
- 'Liodon latispinus is recombined as Platecarpus latispinis'
- 'Liodon mudgei is recombined as Platecarpus mudgei'
- 'Liodon nepaeolicus belongs to Liodon'
- 'Macrosaurus laevis is recombined as Liodon laevis'
- 'Macrosaurus proriger is recombined as Liodon proriger'
- 'Mosasaurus minor is a subjective synonym of Mosasaurus acutidens'
- 'Nectoportheus validus is recombined as Liodon validus'
- 'Ornithotarsus immanis belongs to Ornithotarsus'
- 'Osteopygis erosus belongs to Osteopygis'
- 'Palaeoscincus costatus belongs to Palaeoscincus'
- 'Pelecorapis varius belongs to Pelecorapis'
- 'Plastomenus insignis belongs to Plastomenus'
- 'Plesiosaurus brevifemur belongs to Plesiosaurus'
- 'Polyonax mortuarius belongs to Polyonax'
- 'Rhinosaurus micromus is recombined as Liodon micromus'
- 'Sironectes anguliferus belongs to Sironectes'
- 'Thespesius is a subjective synonym of Hadrosaurus'
- 'Thespesius occidentalis is recombined as Hadrosaurus occidentalis'
- 'Toxochelys serrifer belongs to Toxochelys'
- 'Trachodon mirabilis is recombined as Hadrosaurus mirabilis'
- 'Troodon formosus belongs to Troodon'