310 IMPERFECTION OF THE Chap. IX. 



must have been heated under great pressure, have 

 always seemed to me to require some special explana- 

 tion ; and we may perhaps believe that we see in these 

 large areas, the many formations long anterior to the 

 silurian epoch in a completely metamorphosed con- 

 dition. 



The several difficulties hp^o discussed, namely our not 

 finding in the successive formations infinitely numerous 

 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 paleontologists, namely Cuvier, Owen, Agassiz, 

 Barrande, Falconer, E. Forbes, &c, and all our greatest 

 geologists, as Lyell, Murchison, Sedgwick, &c, have 

 unanimously, often vehemently, maintained the immuta- 

 bility of species. But I have reason to believe that one 

 great authority, Sir Charles Lyell, from further re- 

 flexion 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 last 

 volume alone, relating only to two or three countries. 

 Of this volume, only here and there a short chapter lias 



