New materials of Ordovician nautiloids from Xainza,Tibet

Eastern Taerma bridge-Zhakang was found in recent years to be the second spot of Ordovician outcrop based on reliable fossils. The nautiloids described here include one new genus, two new species and one indeterminate species,which represent only a small fraction of the nautiloids collected from this area. They are new materials of Ordovician nautiloids that have been determined up to now, which enrich Ordovician nautiloid faunal assemblages as well as provide new data to both classification and correlation of the Ordovician for this area and geographical distribution of nautiloid fauna.