The Ancient Volcanoes of Great Britain, Volume 1 (of 2)Note 171 — Chapter XII · CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOESReading editionQuart. Journ. Geol. Soc. vol. xxxiv. (1878), p. 769.◇Copy noteReturn to CHAPTER XII CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOES