The Riochican age is a period of geologic time (57.0—54.0 Ma) within the Paleocene epoch of the Paleogene used more specifically with South American Land Mammal Ages. It follows the Itaboraian and precedes the Casamayoran age. Image:Geological time spiral.png This Geochronology-related article is a stub. You can help Fossil Wiki by [ expanding it].