Lyell, C., Thom, A., & Thom, S. (1850). Principles of geology: Or, The modern changes of the earth and its inhabitants considered as illustrative of geology. (8th and entirely rev. ed.). J. Murray.

Lyell, Charles, et al. Principles of Geology: Or, The Modern Changes of the Earth and Its Inhabitants Considered as Illustrative of Geology. 8th and entirely rev. ed. J. Murray, 1850.