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

April, 1836. coral formations. 567 offers of the peculiar configuration of each class) to deny a great probability to this theory. Its importance, if true, is evident ; because we get at one glance an insight into the system by which the surface of the land has been broken up, in a manner somewhat similar, but certainly far less perfect, to what a geologist would have done who had lived his ten thousand years, and kept a record of the passing changes. We see the law almost established, that linear areas of great extent undergo movements of an astonishing uniformity, and that the bands of elevation and subsidence alternate. Such phenomena at once impress the mind with the idea of a fluid most gradually propelled onwards, from beneath one part of the solid crust to another. I cannot at present do more than allude to some of the results which may be deduced from these views. If we examine the points of eruption over the Pacific and In- dian oceans, we shall find that all the active volcanoes occur within the areas of elevation. (The Asiatic band must be excepted ; inasmuch as we are entirely in want of information of all kinds respecting it.) On the other hand, in the great spaces supposed to be now subsiding, between the Radack and Dangerous Archipelagoes, in the CoraUian sea, and among the atolls which front the west coast of India, not one occurs. If we look at the changes of level as a consequence of the propulsion of fluid matter beneath the crust, as before sug- gested, then the area to which the force is directed might be expected to yield more readily than that whence it was gra- dually retiring. I am the more convinced that the above law is true, because, if we look to other parts of the world, proofs of recent elevation almost invariably occur, where there are active vents : I may instance the West Indies, the Cape de Verds, Canary Islands, southern Italy, Sicily, and other places. But in answer to this, those geologists, who, judging from the history of the isolated volcanic mounds of Europe, were inclined to believe that the level of the ground was con- stantly oscillating up and down, might maintain that on these same areas, the amount of subsidence had been equal to that