102 Geological Society, 



of rock about fourteen feet above high water, and removing the dung 

 of sea fowls, discovered Balani adhering to the stone. 



With respect to the historical evidence of the earthquake of 1822, 

 Mr. Darwin says that he met with no intelligent person who doubted 

 the rise of the land, or with any of the lower order who doubted that 

 the sea had fallen. He mentions also the altered position of the 

 wreck and of the rock in the bay ; and from a part of the fort being 

 in visible from a point ontheland before the earthquake,butvisibleafter- 

 wards, he infers that the movement of the land was unequal*. A 

 further proof of change, obtained for the author by Mr. Alison, is 

 shown by the remains of a sea-wall built in 1680, and over which, 

 up to 1817, the sea broke during the northerly gales. Mr. John 

 Martin, a ship carpenter of Valparaiso, remembers walking in 1819 

 on the beach at the foot of this wall, and he has been frequently 

 obliged to climb up to the street to avoid the sea. This wall is now 

 separated from the bay by two rows of houses, but a portion of what 

 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 19 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 recks 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- 

 * See note * in page 100. 



