[59] See Jukes, Manual of Geology, pp. 138-141; Lyell, Elements of Geology, p. 500.

[60] Jukes, Manual of Geology, p. 140.

[61] See Mantell, Wonders of Geology, pp. 680-2; also 760; Lyell, Elements of Geology, 464, 465.

[62] Elements of Geology, p. 488.

[63] Mantell, Wonders of Geology, p. 67.

[64] Mantell, Wonders of Geology, p. 66.

[65] Id. Ib.

[66] Chemical Technology, Ronalds and Richardson, vol. i., p. 32.

[67] See Lyell, Elements of Geology, 477-81; Jukes, Manual of Geology, 138, 149-53; The English Cyclopædia, Natural History Department, Article, Coal; Mantell, Fossils of the British Museum, Chapter i., Part I.

[68] Page, Advanced Text-Book of Geology, n. 7, pp. 20, 21.