If island formed continent, some species would emerge and immigrate. Everyone admits continents. We can see why Galapagos and C. Verde differ <see _Origin_, Ed. i. p. 398>], depressed and raised. We can see from this repeated action and the time required for a continent, why many more forms than in New Zealand <see _Origin_, Ed. i. p. 389 for a comparison between New Zealand and the Cape> no mammals or other classes <see however, _Origin_, Ed. i. p. 393 for the case of the frog>. We can at once see how it comes when there has been an old channel of migration,--Cordilleras; we can see why Indian Asiatic Flora,--[why species] having a wide range gives better chance of some arriving at new points and being selected, and adapted to new ends. I need hardly remark no necessity for change. Finally, as continent (most extinction <?> during formation of continent) is formed after repeated elevation and depression, and interchange of species we might foretell much extinction, and that the survivor would belong to same type, as the extinct, in same manner as different part of same continent, which were once separated by space as they are by time <see _Origin_, Ed. i. pp. 339 and 349>. As all mammals have descended from one stock, we ought to expect that every continent has been at some time connected, hence obliteration of present ranges. I do not mean that the fossil mammifers found in S. America are the lineal successors <ancestors> of the present forms of S. America: for it is highly improbable that more than one or two cases (who will say how many races after Plata bones) should be found. I believe this from numbers, who have lived,--mere <?> chance of fewness. Moreover in every case from very existence of genera and species only few at one time will leave progeny, under form of new species, to distant ages; and the more distant the ages the fewer the progenitors. An observation may be here appended, bad chance of preservation on rising island, the nurseries of new species, appeal to experience <see _Origin_, Ed. i. p. 292>. This observation may be extended, that in all cases, subsiding land must be, in early stages, less favourable to formation of new species; but it will isolate them, and then if land recommences rising how favourable. As preoccupation is bar to diffusion to species, so would it be to a selected variety. But it would not be if that variety was better fitted to some not fully occupied station; so during elevation or the formation of new stations, is scene for new species. But during elevation not favourable to preservation of fossil (except in caverns <?>); when subsidence highly favourable in early stages to preservation of fossils; when subsidence, less sediment. So that our strata, as