Note 239 — Chapter XIII · THE ERUPTIONS OF LLANDEILO AND BALA AGE

Mr. Dakyns has expressed his belief that the volcanic group lies unconformably on the Skiddaw Slate (Geol. Mag. 1869, pp. 56, 116), and Professor Nicholson has formed the same opinion (op. cit. pp. 105, 167; Proc. Geol. Assoc. vol. iii. p. 106). Mr. Goodchild, however, has shown that in the Cross Fell inlier the oldest tuffs are interstratified with the Skiddaw Slates (Proc. Geol. Assoc. vol. xi. (1889), p. 261). Mr. Ward in mapping the district inserted a complex series of faults along the junction-line between the volcanic series and the Skiddaw Slates. When I went over the ground with him some years before his death I discussed this boundary-line with him and could not adopt his view that it was so dislocated. More recent re-examination has confirmed me in my dissent. A large number of the faults inserted on the Geological Survey map to separate the Skiddaw Slates from the Borrowdale volcanic series cannot be proved, and probably do not exist. Others may be of the nature of "thrust-planes." But see Mr. Ward's explanation of his views, op. cit. p. 48.