MIDDLE TO LATE TELYCHAIN (SILURIAN, LLANDOVERY) GRAPTOLITE ASSEMBLAGES OF CENTRAL WALES

Graptolite faunas from the uppermost turriculatus, crispus, griestonie nsis, crenulata and spiralis Biozones of central Wales are described. Detailed collecting integrated with recent BGS mapping has demonstrate d a new subzone of Torquigraptus carnicus in the uppermost turriculatu s Biozone, a subdivision of the crispus Biozone into three successive subzones of, in ascending order: Monoclimacis? galaensis, Monograptus crispus, and Streptograptus sartorius; an informal subdivision of the griestoniensis Biozone into two successive assemblages, and the presen ce of faunas which can be assigned to the late Telychian crenulata and , probably, the spiralis Biozones. The compositions of these successiv e assemblages are outlined, and selected graptolites are figured and d escribed. These include two new species: Monograptus pseudocommunis an d Streptograptus whitei.