The Ancient Volcanoes of Great Britain, Volume 1 (of 2)Note 175 — Chapter XII · CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOESReading editionAnn. Mag. Nat. Hist. (1890), 6th ser. vi. p. 40.◇Copy noteReturn to CHAPTER XII CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOES