Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

1835. PENCO CASTLK ' ULLOA.' 421 In a ride along the beach of Concepcion Bay, with Mr. Rouse, we examined the solid wall of old Penco Castle, and found on one side the date 1686 and on another 1687. This castle and the adjoining foundations of houses, are so near the level of the sea, that I am surprised the inhabitants should not have feared being frequently inundated, even by tides oiJy a few feet higher than usual. If all this coast has been more or less upheaved during compai-atively modern times, how is it that the foundations of Penco still stand at the water's edge, very little above the level of a high spring tide .? Ulloa remarks, that " the country round the bay, particularly tliat between Talca- huano and Concepcion, within four or five leagues from the shore, is noted for a very singular curiosity, namely, that at the depth of one-half or three-quarters of a yard beneath the surface of the ground, is a stratum of shells of different kinds, two or three toises in thickness, and in some places even more, without any intermixture of earth, one large shell being joined together by smaller, and which also fill the cavities of the larger. From these shells all the lime used in building is made, and large pits are dug in the earth for taking out those shells, and calcining them. Were these strata of shells found only in low and level places, the phenomenon would be more easily accounted for by a supposition no ways improbable, namely, that these parts were formerly covered by the sea, agreeable to an observation we made in our description of Lima. But what renders it surprising is, that the like quar- ries of the same^kind of shells are found on the tops of moun- tains in this country, fifty toises above the level of the sea. I did not indeed personally examine the quarries on the highest of those mountains, but was assured of their existence by persons who had lime-kilns there ; but I saw them myself on the summits of others, at the height of twenty toises above the surface of the sea, and was the more pleased with the sight, as it appeared to me a convincing proof of the universality of the deluge. I am not ignorant that some have attributed tl)is to other causes; but an unanswerable confutation of their