Ancient Geological Clianges in England. 305 



to the deposition of the strata which have been just described. 

 Decisive evidence of this description is to be found in the beds 

 below those of the Isle of Portland ; and, alx)ve the chalk, the 

 proofs of repeated submersion and disclosure are not less clear. 

 The fact, indeed, of great and frequent alteration in the rela- 

 tive level of the sea and land, is so well established, that the only 

 remaining question regards the mode iu which these alterations 

 have been effected, whether by elevation of the land itself, or 

 subsidence in the level of the sea ? and the nature of the force 

 which has produced them ? The discussions upon these points 

 have been some of the most interesting in geology ; but they 

 would lead us far beyond the limits of our present publication. 

 It will be sufficient to say, that the evidence in proof of great 

 and frequent movements of the land itself, both by protrusion 

 and subsidence, and of the connexion of these movements with 

 the operations of volcanoes, is so various and so strong, derived 

 from so many different quarters on the surface of the globe, and 

 every day so much extended by recent inquiry, as almost to 

 demonstrate that these have been the causes by which those 

 great revolutions were effected ; and that, although the actions 

 of the inward forces which protrude the land, has varied greatly 

 in different countries, and at different periods, they are now, and 

 ever have been, incessantly at work in operating present change, 

 and preparing the way for future alteration, in the exterior of 

 the globe. But for the detail of the proofs upon this great and 

 leading point in the theory of the earth, we must refer to vari- 

 ous publications of modern date, and most especially to the 

 writings of Dr Hutton and Mr Playfair, and the more recent 

 extension and beautiful illustration of their doctrines by Mr 

 Lyell. 



These, then, are some of the results to which we are con- 

 ducted by inquiries such as we have been engaged in. They 

 are not like the visions of the old cosmogonists, the creations of 

 fancy, but sound and legitimate consequences, flowing natural- 

 ly and inevitably from the plainest evidence, from facts obtained 

 with great labour, and scrupulously weighed. It is tTiis exer- 

 cise of the intellect to which geological researches so directly 



VOL. \IV. NO. XXVIII. APRIL 1833. U 



