Note 86 — Chapter X · THE CAMBRIAN VOLCANOES OF SOUTH WALES
Reading edition
Quart. Journ. Geol. Soc. vol. xxxix. (1883), p. 294 et seq. While the essential parts of the investigation are given in the following pages, I would refer the reader to this paper for details not transferred to the present volume.
[87] Op. cit. vol. xlvi. (1890), p. 241.