. Bulletin of the British Museum (Natural History). LOWER ORDOVICIAN BRACHIOPODA 25 Sowerbvella Limestones exposed in old trackway SW end of Deer Park, Dynevor Park, Llandeilo (SN 609223); BB 92298-300 from the grey shelly sandstones ('Pebbly Felspar Ash' of the Main Tuff Group) 200 m SW of Cam peak, Cameddau Hills, 125 km ESE of Newmead Farm near Builth Wells (SO 065539); from the 'Llandeilo Limestone' {Nemagrapius gracilis Zone) of Harper's Quarry, Wellfield, 2 km north of Builth (SO 037534); SM from Llanvirn Didymograpius murchisoni shales exposed in Howey Brook (SO 090592
. Bulletin of the British Museum (Natural History). LOWER ORDOVICIAN BRACHIOPODA 25 Sowerbvella Limestones exposed in old trackway SW end of Deer Park, Dynevor Park, Llandeilo (SN 609223); BB 92298-300 from the grey shelly sandstones ('Pebbly Felspar Ash' of the Main Tuff Group) 200 m SW of Cam peak, Cameddau Hills, 125 km ESE of Newmead Farm near Builth Wells (SO 065539); from the 'Llandeilo Limestone' {Nemagrapius gracilis Zone) of Harper's Quarry, Wellfield, 2 km north of Builth (SO 037534); SM from Llanvirn Didymograpius murchisoni shales exposed in Howey Brook (SO 090592); SM A. 104418 from Glyptograptus teretiuscuhis shales exposed in the stream section east of Pen Cerrig (SO 948537). SM A. 104413 from G. teretiuscuhis io N. gracilis Zone shales exposed at Penddol Rocks, in the Wye river section 1 km NW of Builth (SO 031522); GSM 16762 from the 'Llandeilo flags of Builth', probably the same horizon, precise locality unknown. Discussion. The specimens, including GSM 16762, SM , and from localities in the Builth region, allow us to add information on the species' ventral morphology and the variability of its dorsal ornament to the existing description (Williams 1974:44). The small Llandeilo and the usually larger Builth specimens exhibit more variable dorsal capillae densities than apparently conspecific brachial valves from Shelve. Such pronounced variability in ornament may be indicative of specific variation in the Welsh stock. The stratigraphical range of Schizocrania cf salopiensis in the Builth region and in the Llandeilo area (Bassett el al. 1974 : 9; Wilcox 1979 : 42) falls within that of the Shelve stock which is known from Upper Llanvirn, Llandeilo and basal Caradoc Figs 60-65 Schizocrania cf. salopiensis Williams. Fig. 60, SM , internal mould of a pedicle valve X 6, from Llandeilo shales, Penddol, Builth. Fig. 61, SM latex cast of an external mould of a brachial valve x 8. from Llanvirn
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