358 The Rev. D. Williams on the Geology of Devonshire. 



If therefore,"as we now believe, (together with Mr.Lonsdale 

 and Mr. James Sowerby) that these peculiar fossils constitute 

 the links which connect the Carboniferous and Silurian Sy- 

 stems, we have only to produce clear evidences; and this 

 done, we venture to assert, that however indisposed a priori, 

 to admit the necessity of so great and sweeping a re- 

 form, there is no lover of truth (and all true geologists are 

 such) who will not participate in the conviction, that as a few 

 important pages in the early history of the earth have been 

 unfolded for the first time in Devonshire, we are entitled to 

 suggest that the " Devonian System" be henceforth a term 

 admitted into our geological nomenclature. 



P.S. In addition to what we have written in this Journal, 

 we have prepared for reading before the Geological Society, 

 a short expose of our present views concerning the structure 

 of Devon and Cornwall, accompanied by a geological map of 

 the West of England and Wales, which illustrates the amount 

 of change proposed in this new classification. It is also our 

 intention to visit in the course of this summer those districts 

 of France (Britany, &c.) in which the existence of transition 

 coal fields has been maintahied, as we deem it highly proba- 

 ble, that the application of the same principles which have 

 enabled us to classify the rocks of Devon and Cornwall, may 

 be successfully employed in that region of France which seems 

 to be physically connected with the country in question. 

 April 19, 1839, 



LVII. On the Classification of certain Geological Formations 

 in Devonshire. By the Rev. David Williams, F.G.S. 



To the Editors of the Philosophical Magazine and Jour?ial. 

 Gentlemen, 



FEELING assured that Prof. Sedgwick and Mr. Murchison 

 will do me justice with respect to as much of the article 

 in your last Number which implicates me more seriously 

 than any one else, I trouble you only with a few remarks on 

 the hypothesis of Mr. Lonsdale, which they have reanimated 

 and quickened by a new sanction and impulse. Much I ap- 

 prehend will depend on future observations before it can with 

 justice be received or rejected. I always believed the plant and 

 culm-bearing rocks to belong to the upper grauwacke ; and 

 if the carboniferous champions will only modify their views 

 a little, and include the "whole in their old red sandstone 

 group, I know of no difficulty at present to my adopting the 

 theory ; but I must unlearn a great deal before I admit the 



