The Ancient Volcanoes of Great Britain, Volume 1 (of 2)Note 131 — Chapter XII · CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOESReading editionFor references to the older literature see ante, p. 142.◇Copy noteReturn to CHAPTER XII CHARACTERS OF THE SILURIAN SYSTEM IN BRITAIN. THE ARENIG VOLCANOES