1. Arber, Quart. Journ. Geol. Soc, vol. lxv, p. 21, 1909.
2. Kidston, Trans. Roy. Soc. Edinb., vol. xxxv, pt. vi, p. 324, pl. i, fig. 9, 1891.
3. [For review of Geological Survey memoir on the Kent Coal Exploration, just issued, see infra, p. 131.—Edit.]