Castro, on each side of the creek and rivulet of the Gamboa, three distinct
terraces are seen: the lowest was estimated at about one hundred and fifty
feet in height, and the highest at about five hundred feet, with the
country irregularly rising behind it; obscure traces, also, of these same
terraces could be seen along other parts of the coast. There can be no
doubt that their three escarpments record pauses in the elevation of the
island. I may remark that several promontories have the word Huapi, which
signifies in the Indian tongue, island, appended to them, such as
Huapilinao, Huapilacuy, Caucahuapi, etc.; and these, according to Indian
traditions, once existed as islands. In the same manner the term Pulo in
Sumatra is appended to the names of promontories, traditionally said to
have been islands (Marsden's "Sumatra" page 31.); in Sumatra, as in Chiloe,
there are upraised recent shells. The Bay of Carelmapu, on the mainland
north of Chiloe, according to Aguerros, was in 1643 a good harbour
("Descripcion Hist. de la Provincia de Chiloe" page 78. From the account
given by the old Spanish writers, it would appear that several other
harbours, between this point and Concepcion, were formerly much deeper than
they now are.); it is now quite useless, except for boats.

VALDIVIA.

I did not observe here any distinct proofs of recent elevation; but in a
bed of very soft sandstone, forming a fringe-like plain, about sixty feet
in height, round the hills of mica-slate, there are shells of Mytilus,
Crepidula, Solen, Novaculina, and Cytheraea, too imperfect to be
specifically recognised. At Imperial, seventy miles north of Valdivia,
Aguerros states that there are large beds of shells, at a considerable
distance from the coast, which are burnt for lime. (Ibid page 25.) The
island of Mocha, lying a little north of Imperial, was uplifted two feet,
during the earthquake of 1835. ("Voyages of 'Adventure' and 'Beagle'"