448 



appeared to be its base, carefully levelled by a resident engineer, was 

 found to be 11 feet 6 inches above high water mark. Mr, Darwin 

 does not ascribe the whole of this change to the earthquake of 1822, 

 and is of opinion that the alteration then produced was under three feet. 

 The church of San Augustin is believed to have been built in 1 634, 

 and the base of its walls is 1 9 feet 6 inches above high tide level ; 

 but there is a tradition that the sea formerly approached very close 

 to its foundations. Allowing, therefore, 4 feet 6 inches for its protec- 

 tion when built, the amount of change in 220 years is only 15 feet. 

 The granite rocks which form the coast are also water-worn and hol- 

 lowed at about the same height, namely, 14 feet above the present 

 sea level. These data, Mr. Darwin is of opinion, prove, that though 

 the changes in 220 years have been small, yet that they were pre- 

 ceded by a period of comparative rest, during which there was time 

 for any former marks on the rocks to become obliterated. 



The author then described the beds of recent shells between Con- 

 con and Quintero, about 100 feet above the sea level ; the deposits 

 near Plazilla and Catapilco ; and in the valley of Longotomo^ On 

 the hills to the north of the latter, about 200 feet above the sea, 

 immense quantities of recent shells coat the surface or the sides of the 

 ravines ; and hence Mr. Darwin infers that the action of the sea de- 

 termined 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 

 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 Bala- 

 nideas, and this again overlies a sandstone abounding with silicified 

 bones of gigantic sharks mingled with extinct species of oysters and 

 Pernae 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 j yet in the pro- 

 vinces near the mouth of the Plata, earthquakes are never e.xperienced ; 

 anditisimpossibleto suppose that the most violentofthe Chilian earth- 



