thus we have in South America, Alpine humming-birds, Alpine rodents, Alpine plants, etc., all strictly belonging to American forms; and it is obvious that a mountain, as it became slowly upheaved, would be colonised from the surrounding lowlands.
Horrela, Hego Amerikan euli-txori alpetarrak, karraskari alpetarrak, landare alpetarrak... ditugu, amerikar formei hertsiki dagozkienak; eta begi-bistakoa da, mendiek, astiro-astiro jalgitzean, inguruko beterrietako biztanleak hartuko zituztela.