| Hypertragulus(noun, creature, geohistory, appearance, eocene) |
| Hyporhina(noun, creature, geohistory, appearance, eocene) |
| Hypsamasia(noun, fauna, eocene, extinction) |
| Hyracodontidae(noun, creature, geohistory, appearance, eocene) |
| Idrissia(noun, fauna, eocene, extinction) |
| Indricotheriinae(noun, creature, geohistory, appearance, eocene) |
| Ischnochiton(noun, creature, geohistory, appearance, eocene) |
| Lammidhania(noun, fauna, eocene, extinction) |
| Leontiniidae(noun, creature, geohistory, appearance, eocene) |
| Leptomerycinae(noun, creature, geohistory, appearance, eocene) |
| Leptomeryx(noun, creature, geohistory, appearance, eocene) |
| Limnocyon(noun, creature, geohistory, appearance, eocene) |
| Linthia(noun, fauna, eocene, extinction) |
| Lobocarcinus(noun, creature, geohistory, appearance, eocene) |
| Macginitiea(noun, creature, geohistory, appearance, eocene) |
| Macraucheniidae(noun, creature, geohistory, appearance, eocene) |
| Madtsoia(noun, fauna, eocene, extinction) |
| Merycoidodontoidea(noun, creature, geohistory, appearance, eocene) |
| Mesotheriidae(noun, creature, geohistory, appearance, eocene) |
| Metarhinus(noun, fauna, eocene, extinction) |