Article: Ordovician trilobites from the Dawangou Formation, Kalpin, Xinjiang, north-west China
Sixteen trilobite taxa are described from the type section of the Dawangou Formation (late Arenig-early Llanvirn) at Dawangou, Kalpin, north-western Tarim, Xinjiang, north-west China. They include two new genera: the asaphine Mioptychopyge and the pterygometopine Yanhaoia. Evidence from the lithofacies and from the composition and taphonomy of the assemblages suggests that the fauna lived in a generally calm, upper slope environment. More than 80 per cent, of the species are common, or closely allied, to coeval forms in the Yangtze region, indicating a close palaeogeographical relationship between the Tarim and South China blocks during the late early Ordovician. Some genera, such as Birmanites, Eccoptochile, Ovalocephalus and Pseudocalymene, are typical of Gondwanan faunas, and it is likely that the Tarim Block formed part of peri-Gondwana in the Ordovician.