[13]

Sillimans Journ. v. 20. p 378 Péron & Lesueur in Annales du Museum Tom. XV. p. 287 describe variation of shells in proceeding from certain centres. Author (in Bib. Universal. Dec 1830) remarks it is interesting to observe change in horizontal direction on earth's surface as in times past.

["Some interesting observations, formerly made by Peron and Lesuem-, stated in the Annales du Museum, T. XV, p. 287, and which Mr. Lyell has not cited, confirm his opinion that the greater size of individual shells of the same species, is an indication of a change of climate. These naturalists have remarked that every species of marine animals has received a distinct location, confined to certain parts of the ocean, and that in those positions they are found to be larger, and more beautiful. In proportion as they are removed from this locality, they degenerate, and are at length extinct."]