Note 123 — Chapter XI · THE CAMBRIAN VOLCANOES OF NORTH WALES, THE MALVERN HILLS AND WARWICKSHIRE
Reading edition
Mem. Geol. Survey, vol. ii. part i. pp. 52, 55; also Horizontal Sections of the Geol. Survey, Sheet 13, No. 8, and Sheet 15. Reference to the igneous rocks of this area will be found in the remarkable essay by De la Beche in vol. i. of the Mem. Geol. Surv. pp. 34, 38.