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Show 310 IMPERFECTION OF THE CHAP. IX. must have been heated under great pressure, have always seemed to me to require some special ~xplanation; and we may perhaps believe that we se~ In these large areas, the many formations long anterior to the silurian epoch in a- completely metamorphosed con-dition. The several difficulties here discussed, namely our not finding in the successive formations infini~ely n~merous transitional links between the many species which now exist or have existed ; the sudden manner in which whole groups of species appear in our European forma-tions ; the almost entire absence, as at present known, of fossiliferous formations beneath the Silurian strata, are all undoubtedly of the gravest nature. We see this in the plainest manner by the fact that all the most eminent palreontologists, namely Cuvier, Owen, Agassiz, Barrande, Falconer, E. Forbes, &c.; and all our greatest geologists, as Lyell, Murchison, Sedgwick, &c., hav~ unanimously, often vehemently, maintained the immutability of species. But I have reason to believe that one great authority, Sir Charles Lyell, from further reflexion entertains grave doubts on this subject. I feel how rash it is to differ from these great authorities, to whom, with others, we owe all our knowledge. Those who think the natural geological record in any degree perfect, and who do not attach much weight to the facts and arguments of other kinds given in this volume, will undoubtedly at once re· ject my theory. For my part, following out Lyell's metaphor, I look at the natural geological record, as a history of the world imperfectly kept, and written in a changing dialect ; of this history we possess the I.ast volume alone, relating only to two or three countnes. Of this volume, only here and there a short chapter has CHAP. IX. GEOLOGICAL RECORD. 311 been preserved; and of each page, only here and there a few lines. Each word of the slowly-changing language, in which the history is supposed to be written, being more or less different in the interrupted succession of chapters, may represent the apparently abruptly changed forms of life, entombed in our consecutive, but widely separated, formations. On this view, the difficulties above discussed are greatly diminished, or even disappear. |
