Graptolites from the Qilang and Yingan formations (Caradoc, Ordovician) ofKalpin, western Tarim, Xinjiang, China

Late Ordovician rocks of the Qilang and Yingan formations from the Kalpin a rea in the Tarim region of western Xinjiang, China (Tarim palaeoplate) cont ain a moderately diverse graptolite Fauna. The fauna from the Qilang Format ion contains Corynoides calicularis Nicholson, 1867; Dicranograptus clingan i resicis Williams and Bruton, 1983; Lasiograptus costatus Lapworth, 1873: Pseudoclimacograptus scharenbergi (Lapworth, 1876); and Glossograptus sp, a mong other species. This assemblage most likely corresponds to the upper Cl imacograptus (Climacograptus) bicornis Zone? to lower C. (Diplacanthograptu s) lanceolatus Zone of Australia. The Qilang Formation also yields the new taxon, Amplexograptus maxwelli spinousus new subspecies. The overlying Ying an Formation yields a more diverse assemblage that includes Climacograptus (Diplacanthograptus) spiniferus Ruedemann,1912; C. (D.) lanceolatus VandenB erg, 1990; Orthograptus quadrimucronatus (Hall. 1865); Amplexograptus praet ypicalis Riva,1987; Dicellograptus pumilus Lapworth,1876; and D. morrisi Ho pkinson, 1871. This assemblage most likely corresponds to the Corynoides am ericanus Zone through the C. (D.) spiniferus Zone of eastern Laurentia, or to the D. clingani Zone of Scotland and central Newfoundland. The presence of a C. (D.) lanceolatus and C. (D.) spiniferus succession in the Yingan Fo rmation also suggests correlation with the Eastonian I and 2 of Australasia . The Yingan Formation faunas represent an offshore Pacific Province assemb lage dominated by cosmopolitan epipelagic species. The Fauna is most simila r, both in terms of species composition and relative abundance patterns, to those of the Appalachian Basin. The Yingan faunas differ from the latter i n the absence of Laurentian endemic species (except for Amplexograptus prae typicalis), and in the common occurrence of dicellograptids.