Isaii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



of opinion whicli I owe to yourselves, if I did not declare my entire 

 want of faith in the theory of the pentagonal resemi. 



European systems of M. de Beaumont, loith an Examination of 

 some parts of the Evidence on ivhich they are founded. — The theory 

 of the parallelism of contemporaneous lines of elevation, rests, as I 

 have just observed, on its own independent evidence. The amount 

 of evidence brought forward by M. de Beaumont is very great, and 

 is collected from such a variety of sources and depends on the geolo- 

 gical structure of so many regions, that it is extremely difficult to 

 ascertain the exact value of its different portions, and to separate 

 that which constitutes independent evidence from that which in- 

 volves, in a greater or less degree, the fundamental assumptions of 

 the theory itself. All that the individual geologist can do effectively 

 in such an inquiry is to take those regions of which the structure 

 has been most fully investigated, and with which he is best ac- 

 quainted, and to examine critically the evidence which they afford, 

 and the conclusions which have been drawn from it. This is what 

 I shall endeavour to do with respect to some of those parts of our 

 own country with the geological strui^ture of which we are best ac- 

 quainted. It is to these islands that M. de Beaumont has made his 

 most frequent and distinct appeals ; and it is to the evidence hence 

 derived that my criticisms will be almost entirely restricted. There 

 is, as I have intimated, a large mass of evidence derived from other 

 countries which I profess not to discuss. Such a discussion can only 

 be profitably undertaken by those who are more intimately acquainted 

 with the phsenomena appealed to, than any one geologist can gene- 

 rally be beyond a comparatively limited region. In the performance 

 of the restricted task which I thus propose to myself, it will be ab- 

 solutely necessary that I should first lay before you an outline of the 

 geological structure of those parts of our own country to which re- 

 ference will be more especially made. These are the Palaeozoic di- 

 stricts of Wales and the adjoining English counties, and of the North 

 of England, together with the more recent geological district of the 

 south-eastern part of this country. In this sketch my object will be 

 to direct your attention to those phsenomena only which bear directly 

 pn the questions before us. And here let me remark, that if, in dis- 

 cussing so comprehensive a theory as the one before us, I may appear 

 to found objections on phsenomena extending over areas of too limited 

 extent, the obvious answer will be that they are only the areas to 

 which M. de Beaumont has himself appealed for the establishment 

 of his theory. And further, Gentlemen, let it not be thought that 

 my objections are urged with any cavilling spirit of hostility to the 

 theory of this distinguished geologist, but with a sincere desire of 

 eliciting; truth, and of elevating; the noble science we cultivate into its 

 proper place among the more rigorous inductive sciences. This 

 theory is not brought before us in that vague and indeterminate form 

 which might render it little more than an appeal to our imagination, 

 but as one which, with an entire claim to the candour of criticism, 

 shuns not its severity. It is with this feeling that I have entered 

 upon the task which I have prescribed to myself in this address ; and 



