New Silurian graptolite material from Nyalam, southern Xizang (Tibet), China
Silurian graptolite-bearing strata in Nyalam County are one of the few known sources of Silurian graptolites in southern Xizang (Tibet). Recent graptolite collections from the Shiqipo Formation at Yalai Village, Nyalam County, contain Normalograptus sp., Glyptograptus sp., Campograptus lobiferus, C. cf. lobiferus, C. cf. obtusus, C.? circularis, Lituigraptus cf. convolutus, Rastrites cf. perfectus, Stimulograptus sedgwickii, Streptograptus sp. and Torquigraptus decipiens. This assemblage indicates a late Aeronian (Llandovery) age (Lituigraptus convolutus to Stimu- lograptus sedgwickii biozones). This new finding provides the potential for the correlation of Silurian strata between Xizang (Tibet) and other parts of the world.