All Volcanic Valleys and Depressions

This group collects the Volcanic Formations subcategory's members whose own description identifies them as a valley, depression or basin of volcanic origin rather than a standing volcanic edifice: the Valley of Mexico's volcanic basin, the Piedras Encimadas valley system, the Tunkin Depression volcanic field and a Kenyan volcano's own rift-valley depression. These are grouped apart from the subcategory's cone, dome and plug groups because a valley or basin is a negative, low-lying landform rather than a positive, raised one.