122 bulletin: museum of comparative zoology. 



"It is simply monstrous to suppose that the terraces on a dead level 

 for leagues along the coast, and miles in breadth, and covered with 

 beds of stratified gravels 10 to 30 feet in thickness, are due to sub- 

 aerial denudation." 



Darwin seems here to have forgotten what he wrote on the shells 

 embedded in a friable calcareous rock in the terraces of Coquimbo at 

 a height of 250 feet. "Although I examined so many hundreds of 

 miles of coast on the Pacific, as well as Atlantic side of the continent, 

 I found no regular strata containing sea-shells of recent species, 

 excepting at this place, and at a few points northward on the road to 

 Guasco. This fact appears to me highly remarkable; for the expla- 

 nation generally given by geologists, of the absence of stratified 

 fossiliferous deposits of a given period, namely, that the surface then 

 existed as dry land, is not here applicable; for we know from the 

 shells strewed on the surface and embedded in loose sand or mould, 

 that the land for thousands of miles along both coasts has been lately 

 submerged." (1845, p. 344.) 



The interpretation of the shells strewed on the surface and embedded 

 in the loose sand or mould constitutes the essential difference between 

 Darwin's hypothesis of their marine deposition and the theory that 

 such surficial deposits pertain to the group of kitchen-midden. 



M}^ own observations of the coast of Chile were made about Corral 

 and Valdi^da in latitude 40° S., at Talcahuano and Concepcion, in 

 latitude 35° 35' S., and with less scope about Valparaiso in latitude 

 33° S. 



The Coast at Corral and Valdivia. Of Valdivia, Darwin (1891, p. 

 236) states " I did not observe 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 recognized." 



The plain or rather terrace which Darwin mentions extends from the 

 open coast outside of Corral entrance (Plate 29), about the sides of 

 the harbor of Corral and up the Valdivia River to the city of that name. 

 It is well shown about the sides of Manzera Island in the harbor of 

 Corral (Plate 30), and is a distinct feature along the banks of the 

 Valdivia River (Plate 31). It is a terrace of denudation sometimes 

 cut in the soft Tertiary sandstones mentioned by Darwin, sometimes 

 in conglomerates as at Corral, and sometimes in the schists. About 

 Valdivia and Teja Island this terrace I estimated to be fifty-five feet 

 above the sea-level and the same along the Rio Cruces Channel. The 



