Note 221 — Chapter XXXVI · THE PLATEAUX
Reading edition
Quart. Journ. Geol. Soc. vol. xlvi. (1890), p. 356. Professor Judd has there described under the name of "propylites" various members of the volcanic series which he believes to have undergone alteration from solfataric action. I have not been able to discover any trace of such action, but I have found that the lavas of the plateaux assume a peculiar condition where they have been affected by large intrusive masses of granophyre or gabbro. (See postea, Chapter xlvi.)