[497-B] Ibid. p. 38.

[498-A] I am indebted to Sir H. De la Beche for this information. See also maps and sections of Irish Survey.

[498-B] Sir H. De la Beche, MS. notes on Irish Survey.

[499-A] Report on Geology of Cornwall, p. 310.

[501-A] See Principles of Geol., Book 3.

[501-B] See the author's Anniv. Address to the Geol. Soc. 1837. Proceedings of G. S. No. 49. p. 520.

Transcriber's Notes:

Illustrations have been moved from the middle of a paragraph to the closest paragraph break, the following illustrations have been moved to another page: