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

668 A FEW KEMARKS are at least five grand alternations of such rocks, and aqueous sedimentary deposits, amounting in thickness to several thou- sand feet."* These wonderful alternations of the consequences of fire and flood, are, to me, indubitable proofs of that tremen- dous catastrophe which alone could have caused them; — of that awful combination of water and volcanic agency which is shadowed forth to our minds by the expression " the fountains of the great deep were broken up, and the windows of heaven were opened." The upheaval of the island of Santa Maria has been quoted by geologists, from my statement'; and it will be interesting to learn whether that island has remained at its new elevation, or whether, like the shore at Talcahuano,-f- it has sunk down again. If the coast in that neighbourhood has been gradually rising, it is strange that old Penco Castle should still stand so low (p. 421). In Mr. Lyell's Elements of Geology, } he mentions Mr. Darwin having found, near Callao, " at the altitude of eighty- five feet above the sea, pieces of cotton thread, plaited rush, and the head of a stalk of Indian corn, all of which had evidently been imbedded with the shells" (marine). "At the same height on the neighbouring mainland, he found other signs corroborating the opinion that the ancient bed of the sea had there also been uplifted eighty-five feet, since the region was first peopled by the Peruvian race." The neighbourhood of Lima has suffered from immense waves caused by earthquakes, and the relics found among the shells may have been scattered by one of those waves. The bed of shells may have been disturbed by the earthquake and its consequences, the ground may have been rent, and afterwards closed again, or the opening may have been filled up by loose earth and anything lying on it, as has taken place at Concepcion. That the country near Callao, or Lima, has not been upheaved, to any sensible amount, since the last great earthquake, which was accompanied by a wave that * Mr. Darwin's letters to Pjofessor Henslow : printed for the Cam- bridge Philosophical Society — 1835. t See pages 420-1. | 1838, pp. 295-6.