1804 in paleontology
Mammals
- Georges Cuvier describes fossil from the Paris Basin. He determines that two particular taxa based on their fossils were similar to modern mammals such as tapirs, camels, or ruminants but otherwise were not close analogues. He names the perissodactyl Palaeotherium and the artiodactyl Anoplotherium.
New taxa
| Taxon | Novelty | Status | Author | Age | Unit | Location | Notes | Images |
| Palaeotherium | Gen. nov. | Valid | Cuvier | Late Eocene | Paris Basin |  France |