Cordillera in relation to the absence of the sea on this side. Yet I must own I have long felt a little sceptical on the proximity of water being the exciting cause. The one volcano in the interior of Asia is said, I think, to be near great lakes; but if lakes are so important, why are there not many other volcanoes within other continents? I have always felt rather inclined to look at the position of volcanoes on the borders of continents, as resulting from coast lines being the lines of separation between areas of elevation and subsidence. But it is useless in me troubling you with my old speculations. LETTER 494. TO A.R. WALLACE. March 22nd [1869]. (494/1. The following extract from a letter to Mr. Wallace refers to his "Malay Archipelago," 1869.) I have only one criticism of a general nature, and I am not sure that other geologists would agree with me. You repeatedly speak as if the pouring out of lava, etc., from volcanoes actually caused the subsidence of an adjoining area. I quite agree that areas undergoing opposite movements are somehow connected; but volcanic outbursts must, I think, be looked at as mere accidents in the swelling up of a great dome or surface of plutonic rocks, and there seems no more reason to conclude that such swelling or elevation in mass is the cause of the subsidence, than that the subsidence is the cause of the elevation, which latter view is indeed held by some geologists. I have regretted to find so little about the habits of the many animals which you have seen. LETTER 495. TO C. LYELL. Down, May 20th, 1869.