"Life and Letters," I., page 82.

Some account of the origin of his evolutionary views is given in a letter to Jenyns (Blomefield), "Life and Letters," II.

page 34.) a passage in which the writer describes the deep impression made on his mind by certain groups of facts observed in South America.

Mr.Huxley goes on: "The facts to which reference is here made were, without doubt, eminently fitted to attract the attention of a philosophical thinker; but, until the relations of the existing with the extinct species, and of the species of the different geographical areas with one another, were determined with some exactness, they afforded but an unsafe foundation for speculation.
It was not possible that this determination should have been effected before the return of the "Beagle" to England; and thus the date (Chapter II./4.

The date in question is July 1837, when he "opened first note-book on Transmutation of Species.') which Darwin (writing in 1837) assigns to the dawn of the new light which was rising in his mind, becomes intelligible." This seems to us inconsistent with Darwin's own statement that it was especially the character of the "species on Galapagos Archipelago" which had impressed him.