Geological Society of London. 175 



Elie de Beaumont respecting the parallelism of contemporaneous eleva- 

 tions, whether true or false, could not fail to give an additional interest 

 to geological researches, conducted on so large a scale as those of Prof. 

 Sedgwick. Mr Murchison's mode of investigation may be described thus : 

 that he has applied, for the first time, to the rocks below the old red 

 sandstone, the method of classification previously employed with so much 

 success for the oolites. It is truly remarkable, that Nature has placed 

 in this our corner of the world, series, probably the most complete which 

 exist, of both these groups of strata ; and as the oohtcs of England have 

 long been the type of that portion of European geology, the Silurians of 

 Wales may perhaps soon be recognised as the standard members of a still 

 more extensive range of deposits. As if Nature wished to imitate our 

 geological maps, she has placed in the corner of Europe our island, con- 

 taining an Index Series of European formations in full detail. 



" The Carboniferous, Old Red, Silurian, and Cambrian systems have, 

 by many writers, up to the present time, been all comprehended in the 

 term " transition rocks," so far as that term has been used with any de- 

 finite application at all. The analysis of this vague group into these dis- 

 tinct portions, removes the confusion and perplexity which have hitherto 

 prevailed in this province of geology. Prof. Sedgwick has further pro- 

 posed to apply the term Palceozoic ; and Mr Murchison that of Protozoic, 

 to the rocks which constitute the Cambrian and Silurian systems. 



" How far these appellations are useful, we shall see when we liave 

 had speculations presented to us in which they are familiarly used ; for 

 necessity is the best apology, and convenience the best rule, of innova- 

 tions in scientific language. In the names applied to the members of the 

 Silurian system, Mr Murchison, following those examples of geological 

 nomenclature which have been most clearly understood, and most gene- 

 rally adopted, has borrowed his terms from localities in which standard 

 types of each stratum occur. If the Silurian system be as exclusively dif- 

 fused as some indications seem to imply, we may find the Ludlow rocks 

 in Scandinavia, and the Caradoc sandstone even in Patagonia. Whether 

 a like identification of the more ancient rocks of the Cambrian series with 

 the lowest formations of other countries be possible, may perhaps be (for 

 the present) more doubtful. 



" I have spoken of Mr Murchison's work as if it had formed part of 

 our Proceedings, as, indeed, almost every part of it has done, although it 

 now appears in a separate form. And I will add, that it is impossible not 

 to look with pleasure upon the form in which the work appears, enriched 

 as it is in the most liberal manner, with every illustration, map^ and sec- 

 tion, picturesque view, and well-marked fossil, which can aid in bring- 

 ing vividly before the reader all the instructive and interesting features of 

 the formations there described. The book must be looked upon as an 

 admirable example of the sober and useful splendour which may grace a 

 geological monograph. 



" Having been tempted to dwell so long on this subject from my con- 



