Note 109 — Chapter XXXII · PERMIAN VOLCANOES OF ENGLAND
Reading edition
Geol. Mag. 1892, p. 250. The rocks have been more recently described by Mr. B. Hobson, Quart. Jour. Geol. Soc. vol. xlviii. (1892), p. 502. The rock of Kellerton Park is called by Mr. Hobson "mica-augite-andesite," and he gives a chemical analysis of it by Mr. E. Haworth, op. cit. p. 507. Mr. Watts has lately found one of the orthoclase rocks to be rich in olivine.
[110] See De la Beche, Report, pp. 203, 204. My colleague, Mr. Ussher, found close to the Thurlestone outlier of conglomerate near Kingsbridge, Devonshire, a small boss of quartz-porphyry which rises through and alters the Devonian rocks. The actual junction of this mass with the conglomerate is not seen, nor have any fragments of the porphyry been noticed among the pebbles.
Mr. Ussher informs me that in the quarry the visible exposure of the acid rock is surrounded an covered by mica-porphyrite, probably andesite.