Juchipila Formation
The Juchipila Formation is a geologic formation in Mexico. It preserves fossils dating back to the Neogene period.<ref name="carranzacastanedaetal2013"/ Closely corresponding to the other Hemphillian faunal assemblages of North America, it is significant for understanding the palaeofauna of Miocene and Pliocene central Mexico. Paleoenvironment. The paleoenvironment of the Juchipila Formation was largely terrestrial in nature. The El Mixton locality consists of a shallow lacustrine succession, beginning near the bottom of an arroyo. Ostracods and gastropods are abundant in these deposits. A thin bed of unconsolidated white ash-fall material, consisting of felsic glass shards and small, overlies the  shallow lacustrine succession of the El Mixton locality. In this part of the succession, camelid and proboscidian footprints are known. The loose paleosols of the El Mixton contain mammal fossils, including the canid "Borophagus" and the equid "Dinohippus". The terrestrial Puente de Cofradía locality bears fossils of "Calippus" and "Cosoryx". The volcaniclastic sandstone of the El Resbalón bears indeterminate megalonychids and antilocaprids. Paleobiota. The Juchipila Formation has yielded a rich variety of extinct mammals.