Note 232 — Chapter XIII
Reading edition
Geological Researches; by Sir Henry De la Beche, C.B. (Degradation of Mountains, p. 167.) Geological Manual, p. 184. Principles of Geology; by Sir Charles Lyell, 7th Edition, p. 150, 686. On the Denudation of South Wales, and the adjacent countries of England; by Professor Andrew Ramsay; Memoirs of the Geological Survey and Museum of Practical Geology, vol. i. p. 297.