Th^Silutinn System. 857 



Wheri we take leave of Wales, where the tombs of primeval life 

 are obscured by numerous sheets of porphyry and other igneous rocks, 

 how clearly do we read in the book of nature, opened out in the north of 

 continental Murope, that Silurian fossils constitute the earliest recog- 

 nisable creation. This fact I have explained in the first chapters 

 of *' Russia and the Ural Mountains." It is also proved in tho works 

 of Barrande on Bohemia, Hall and other geologists in tho United 

 States, and in Canada by Logan. In all these countries, as well as 

 in France and Spain, where they have been analysed by De Venieuil 

 and his countrymen, or in Portugal, where they have been recognised 

 by Daniel Sharpe, the lowest discoverable fossils have been invariably 

 identified as Silurian ; whilst Bronn, in Germany, and D'Orbigny, 

 in France, have so tabulated them. > uU o<u 



In conclusion, I may remark, that if my friend's suggestion wcjre 

 capable of adoption, a result must follow, which even in his zeal to 

 animate his Cambrian rocks, he could not wish to carry out — viz., 

 the erasure of the word Silurian from tho geological maps of the con- 

 tinent of Europe, and even from those of Scotland and Ireland ! In 

 most of these regions, wherever Silurian rocks exist, it is their lower 

 part only which prevails ; and hence all such strata may be claimed 

 as Cambrian, on the very same grounds as those which recently in- 

 duced Professor Sedgwick to term " Cambrian" a ridge of rocks in 

 South Cornwall, which, from its well-known imbedded fossils, was 

 pronounced by me to be Silurian, in 1846. On the same principle, 

 the tracts of the north of Ireland, described as Silurian by Portlock, 

 must now change to " Cambrian ;'* and even the very Irish fossils 

 collected by Griffith,* and named Silurian by that author and M'Coy, 

 must be rebaptized. These, and the great mass of the Scottish and 

 continental rocks of this age, offer scarcely any representatives of tlie 

 upper Silurian group ; and hence, if deprived of all lower Silurian 

 strata, the now wide-spread Silurian system would be almost restricted 

 to the borders of England and Wales, a part of Cumberland, and the 

 island of Gothland. 



As this must inevitably be the issue, if the proposed division of 

 the older British rocks were generally applied, I have been compelled 

 to state my objections plainly, and to point out the confusion and 

 vast changes which must ensue, if a nomenclature be disturbed, which, 

 founded on a natural arrangement, has been extended by my con- 

 temporaries to all quarters of the globe. 



Roderick. Impjjy Murchisox. 



P,S. — The following poetical squib from the pen of a nmtual 

 friend and a profound naturalist, who listened to tho recent discus- 

 sion on this subject, at the Geological Society, may prove more effec- 

 tive than my prose, in sustaining the rights of Sihiria and Cai-ac- 

 tacus : — 



* Author of the (ieologicnl Map of Ireland. 



