^{page 71 note 1} These gravels have provided the Southern Railway with much ballast for many years, and they form a cliff or mound about 50 ft. high in the Axe Valley. The cliff rests upon clay and the implements occur at a depth of about 40 ft. below the surface. Among the references to this subject are: Memoir on the Geology of Sidmouth and Lyme Regis, 1911; Salter, A. E., Proc. Geol. Assoc, xv, 282Google Scholar; D'Urban, , Geol. Mag., 1878, p. 37CrossRefGoogle Scholar; SirEvans, John, Report Brit. Assoc., 1877, p. 116Google Scholar; Parfitt, E., Trans. Devon Assoc, xvi, 501–4Google Scholar.