Page:Darwin Journal of Researches.djvu/13

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POSTSCRIPT.

I the opportunity of a new edition of my Journal to correct a few errors. At page 83 I have stated that the majority of the shells which were embedded with the extinct mammals at Punta Alta, in Bahia Blanca, were still living species. These shells have since been examined (see ‘Geological Observations in South America,’ p. 83) by M. Alcide d'Orbigny, and he pronounces them all to be recent. M. Aug. Bravard has lately described, in a Spanish work ‘Observaciones Geologicas,’ 1857), this district, and he believes that the bones of the extinct mammals were washed out of the underlying Pampean deposit, and subsequently became embedded with the still existing shells ; but I am not convinced by his remarks. M. Bravard believes that the whole enormous Pampean deposit is a sub-aërial formation, like sand-dunes : this seems to me to be an untenable doctrine.

At page 378 I give a list of the birds inhabiting the Galapagos Archipelago. The progress of research has shown that some of these birds, which were then thought to be confined to the islands, occur on the American continent. The eminent ornithologist, Mr. Sclater, informs me that this is the case with the Strix punctatissima and Pyrocephalus nanus ; and probably with the Otus galapagoensis and Zenaida galapagoensis : so that the number of endemic birds is reduced to twenty-three, or probably to twenty-one. Mr. Sclater thinks that one or two of these endemic forms should be ranked rather as varieties than species, which always seemed to me probable.

The snake mentioned at page 381, as being, on the authority of M. Bibron, the same with a Chilian species, is stated by Dr. Günter (Zoolog. Soc., Jan. 24th, 1859) to be a peculiar species, not known to inhabit any other country.

Feb. 1st, 1860.