Note 146 — Chapter XII · CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOES
Reading edition
Quart. Journ. Geol. Soc., vol. xlv. (1889), p. 424; Geol. Mag. (1890), p. 447.
[147] Op. cit. p. 429. A tuff lying below the ironstone near Cross Foxes, east of Dolgelly, likewise contains fragments of trachytic lavas.