Integrated Silurian chitinozoan and graptolite biostratigraphy of the Banwy River section, Wales

The succession of 38 upper Llandovery-lower Wenlock chitinozoan taxa from g raptolitic horizons in the Banwy River section (Powys, Wales) is described. Five new species are named: Bursachitina nestorae, Conochitina leviscapula e, Conochitina mathrafalensis, Belonechitina cavei and Belonechitina meifod ensis. A further ten taxa are described under open nomenclature. Seven chit inozoan biozones are recognized in the Banwy River section, three of which (Cingulochitina bouniensis, Conochitina acuminata and Salopochitina bella) are new. The base of each biozone is correlated with the graptolite biostra tigraphical scheme as follows: Angochitina longicollis Biozone - upper spir alis Biozone; Conochitina acuminata Biozone - lowermost lapworthi Biozone; Margachitina banwyensis Biozone upper lapworthi Biozone; Margachitina marga titana Biozone - lowermost insectus Biozone; Cingulochitina bouniensis Bioz one - upper murchisoni Biozone; Salopochitina bella Biozone - upper firmus Biozone. The succession of chitinozoan biozones in the Banwy River section is compared with that in other sections which have graptolite biostratigrap hical control. This has highlighted the following: (1) the correlation of t he base of the dolioliformis Biozone with the graptolite biozonation is imp recise; (2) E. doliolifonnis is recorded only from levels after the first A . longicollis in Sweden (although this may reflect previously unrecognized synonymies); (3) the longicollis Biozone may be diachronous, its base corre lating with levels low in the Telychian in Sweden, Norway and Estonia and w ith the upper Telychian spiralis Biozone in Wales and the Prague Basin; (4) data herein and from the Prague Basin indicate that the base of the margar itana Biozone correlates with a level low in the insectus Biozone.