John Allen Howe

“ The group is poor in fossils with the exception of graptolites; of these Cyrtograptus grayae and Monograptus exiguus are zonal forms. The Tarannon group is represented by the Rhyader Pale Shales in Radnorshire; by the Browgill beds, with Monograptus crispus and M. turriculatus, in the Lake district; in the Moffat Silurian belt in south Scotland by a thick development, including the Hawick rocks and Ardwell beds, and the Queensberry group or Gala (Grieston shales, Buckholm grits and Abbotsford flags) ”

“ In south Scotland in the central and southern belt of Silurian rocks, which extends across the country from Luce Bay to St Abb’s Head, the Birkhill shales, a highly crumpled series of graptolitic beds, represent the Llandovery horizon. In the Girvan area to the north their place is taken by the Camregan, Shaugh Hill and Mullock Hill groups. In Ireland the Llandovery rocks are represented by the Anascaul slates of the Dingle promontory, by the Owenduff and Gowlaun grits, Co. ”