| Hypisodus(noun, fauna, extinction, chattian) |
| Hyposaurus(noun, extinction, paleocene, genus) |
| Hypsamasia(noun, fauna, eocene, extinction) |
| Hyracotherium(noun, fauna, extinction, lutetian) |
| Idrissia(noun, fauna, eocene, extinction) |
| Ilariidae(noun, fauna, extinction, chattian) |
| Isocrania(noun, extinction, paleocene, genus) |
| Isotemnidae(noun, fauna, extinction, chattian) |
| Jiangxia(noun, extinction, paleocene, genus) |
| Kankatodus(noun, extinction, paleocene, genus) |
| Kimbetohia(noun, extinction, paleocene, genus) |
| Kingena(noun, extinction, paleocene, genus) |
| Krauseia(noun, extinction, paleocene, genus) |
| Lambdopsalis(noun, extinction, paleocene, genus) |
| Lammidhania(noun, fauna, eocene, extinction) |
| Leptaucheniinae(noun, fauna, extinction, chattian) |
| Leptictidium(noun, fauna, extinction, priabonian) |
| Leptomeryx(noun, fauna, extinction, chattian) |
| Leptoreodon(noun, fauna, extinction, priabonian) |
| Leptotragulus(noun, fauna, extinction, priabonian) |