Volume 1

The collected papers of Charles Darwin / edited by Paul H. Barrett ; with a foreword by Theodosius Dobzhansky.

  • Charles Darwin
Date:
1977
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The collected papers of Charles Darwin / edited by Paul H. Barrett ; with a foreword by Theodosius Dobzhansky. Source: Wellcome Collection.

    65/304 (page 43)
    Darwin infers that the action of the sea determined the minor inequalities of the land. Similar deposits, more or less abounding in shells, were noticed by him near Guachen, and in the valley of Quilimap. Close to Conchali, on the south side of the bay, are two very distinct terrace-like plains, the lower being about sixty feet high. Mr. Darwin then gave a very brief notice respecting the marine origin of the terraces at Coquimbo, described by Capt. Basil Hall 1 2 3 and discussed by Mr. Lyell. The proofs of the origin assigned to them rest on the occurrence of recent shells in a friable calcareous rock elevated 250 feet above the sea. This calcareous stratum passes downwards into a shelly mass chiefly composed of fragments of Balanideae, and this again overlies a sandstone abounding with silicified bones of gigantic sharks mingled with extinct species of oysters and Pernae 4 of a great size. The intermediate bed contains some shells in common with the upper, in which all are recent, and with the lowest in which the greater number are extinct. The phenomena of the parallel terraces and the elevated shells occur in a strongly marked manner in the villages of Guasco and Copiapo, the latter being 350 miles to the north of Valparaiso: recent shells also occur at different elevations at an equal distance to the south of it at Concepcion and Imperial. Mr. Darwin believes that the land on the coast of Chili has risen, though insensibly, since 1822. In the Island of Chiloe he is fully convinced, from oral testimony and the state of the coast, that a change effected imperceptibly is now in progress. In support of this gradual rise, independent of earthquakes, he states, that the eastern coast of South America, bordering the Atlantic from the Rio Plata to the Strait of Magellan, presents terraces containing recent shells; yet in the provinces near the mouth of the Plata, earthquakes are never experienced; and it is impossible to suppose that the most violent of the Chilian earthquakes could produce these effects, as the shocks are scarcely transmitted to the plains at the western foot of the Cordilleras. Hence, he concludes, that the earthquakes, volcanic eruptions, and sudden elevations on the coast line of the Pacific, ought to be considered as irregularities of action in some more widely extended phenomenon. 1. [Presented at the meeting of 4 January 1837.] Proceedings of the Geological Society of London 2(1838):446-49.| 2. ... a part of the fort previously invisible is stated to have become visible; but this apparent discrepancy arises from the observations alluded to by Mr. Caldcleugh having been made from the shipping, and those by Mr. Darwin from a point on the land. 3. Basil Hall, author of Extracts from a Journal Written on the Coasts of Chili, Peru, and Mexico, in the Years 1820, 1821, 1822, 3d ed., 2 vols. (Edinburgh: Constable, 1824). T 4. Oysterlike clam.T