Dinosaurs are usually classified as reptiles, but some authors give them their own class, Dinosauria. Dinosaur fossils have not been found in Kentucky. Cretaceous (the last period in the Age of Dinosaurs) sediments that have the potential of containing dinosaur fossils occur in the Jackson Purchase Region in extreme western Kentucky . Rocks across the rest of the state are older than the dinosaurs, so do not contain their fossils. However, many amateur collectors claim to have found dinosaur bones. These inevitably end up being some other fossil or a pseudofossil. Pseudofossils are rocks that have shapes similar to fossils, but are not really fossils. Fossils thought to be dinosaur teeth generally are horn corals or some other type of horn-shaped invertebrate fossil. Presumed dinosaur bones are often cephalopod (a shelled squid), plant (root and stem) fossils, or mineral nodules, such as siderite. Dinosaur eggs that have been reported are generally mineral nodules , either limestone or siderite. Dinosaur skin imprints that have been brought to the geological survey are actually bark impressions of fossil trees called scale trees (so-called because their bark looks like scales). These are all easy mistakes to make. Hoaxes also turn up on occasion. Be wary of trading or buying material claimed to be of dinosaur origin if it was found in Kentucky .
- Amphibia (salamander-like)
- Aves (bird fossils)
- Pisces (fish and shark)
- Mammalia (mammoths, mastodons......)
- Reptilia (lizard-like)