The Ancient Volcanoes of Great Britain, Volume 1 (of 2)Note 168 — Chapter XII · CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOESReading editionOp. cit. p. 339.◇Copy noteReturn to CHAPTER XII CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOES