It contains vertebrate fossils that date it to early to middle Miocene in age.

[4] The formation is interpreted as eolian deposits derived from volcaniclastics of the Jemez volcanic field.

[5] The Piera Parada Member contains fossils mostly of camels (Stenomylus, Oxydactylus, and Michenia) and rhinos (Diceratherium.)

These are characteristic of the late Arikareean faunal stage, 22 to 19 million years ago.

These include specimens of Menoceras, Protolabis, Aepycamelus, Subparacosoryx, Promartes, Tomarctus, Cynarctoides,[1] and Blickomylus.