Charles Lyell: Idézetek angolul
Forrás: The Geological Evidences of the Antiquity of Man (1863), Ch.21, p. 421
Forrás: The Geological Evidences of the Antiquity of Man (1863), Ch.21, p. 417-418
Forrás: The Geological Evidences of the Antiquity of Man (1863), Ch.20, p. 386
Forrás: The Geological Evidences of the Antiquity of Man (1863), Ch.21, p. 410