Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.3)

380 CONCEPCION. Marchj 1835. spaces, and strange subterranean noises likewise heard over nearly equal areas, yet few cases are on record of volcanoes, very far distant from each other, bursting out at the same moment of time. In this instance, however, at the same hour when the whole country around Concepcion was permanently elevated, a train of volcanoes situated in the Andes, in front of Chiloe, instantaneously spouted out a dark column of smoke, and during the subsequent year continued in uncommon activity. It is, moreover, a very interesting circumstance, that, in the immediate neighbour- hood, these eruptions entirely relieved the trembling ground, although at a little distance, and in sight of the volcanoes, the island of Chiloe was strongly affected. To the north- ward, a volcano burst out at the bottom of the sea adjoining the island of Juan Fernandez, and several of the great chim- neys in the Cordillera of central Chile commenced a fresh period of activity. We thus see a permanent elevation of the land, renewed activity through habitual vents, and a submarine outburst, forming parts of one great phenomenon. The extent of country throughout which the subterranean forces were thus unequivocally displayed, measures 700 by 400 geographical miles. From several considerations, which I have not space here to enter on, and especially from the number of intermediate points whence liquefied matter was ejected, we can scarcely avoid the conclusion, however fearful it may be, that a vast lake of melted matter, of an area nearly doubUng in extent that of the Black Sea, is spread out beneath a mere crust of solid land. The elevation of the land to the amount of some feet during these earthquakes, appears to be a paroxysmal move- ment, in a series of lesser and even insensible steps, by which the whole west coast of South America has been raised above the level of the sea. In the same manner, the most violent explosion from any volcano is merely one in a series of lesser eruptions : and we have seen that both these phonomena, which are in so many ways related, are parts of one common action, only modified by local circum-