Mantell, Gideon Algernon; Jones (1857). The Wonders of Geology. Vol. I. Thomas Rupert (7th ed.). London: Henry G. Bohn. p. 371. Archived from the original on 21 April 2021. Retrieved 27 October 2013.
Mantell, Gideon Algernon; Jones (1857). The Wonders of Geology. Vol. I. Thomas Rupert (7th ed.). London: Henry G. Bohn. p. 371. Archived from the original on 21 April 2021. Retrieved 27 October 2013.