The Biblián Formation is an Early Miocene (Colhuehuapian in the SALMA classification) geologic formation of the Cuenca Basin in Ecuador. Fossils of the endemic species Xenastrapotherium aequatorialis have been found in the formation. X.aequatorialis It is the oldest species of its genus Point 354989 Anzogues Topographic Sheet Ecuador at Fossilworks.org
See also List of fossiliferous stratigraphic units in Ecuador
References
Further reading S. E. Johnson and R. H. Madden. 1997. Uruguaytheriine Astrapotheres of Tropical South America. In R. F. Kay, R. H. Madden, R. L. Cifelli, J. J. Flynn (eds.), Vertebrate Paleontology in the Neotropics. The Miocene fauna of La Venta, Colombia 355-382