and the Palaozoic System of England. 491 



elassificatioii, m^ consequently of nomenclature, given in the 

 Tabular View {supra, p. 362) is true for the whole Cambrian 

 series, — that it is the only approach to a good analysis of this 

 series which has yet been given — that it was worked out correctly 

 by my own labours among the older rocks of Wales, and has the 

 claim of priority — that it is geographically appropriate ; that 

 it is physically true, because it makes a break between the Cam- 

 brian and the overlying Silurian series where nature herself had 

 made it- — and lastly, that it is palseontologically true, inasmuch 

 as that break is followed by an immediate and great change of 

 the fossil species. It is true, exactly for the same reason that 

 Smith\s original classification and nomenclature (however un- 

 qouth and harsh sounding) of the Oolitic series was true — because 

 founded on true sections backed by lists of fossils. It is true, 

 for the same reason that Mr. Prestwich's analysis of the deposits 

 above our chalk is true. Lastly, it is true, for the same reason 

 that the classification and nomenclature of the '' Upper Silurian '^ 

 rocks is true. Nor is there, in the past history of British geology, 

 any example of a single group, or series of groups, which has 

 stood its ground and been established, except on principles like 

 those which I have, I believe, correctly followed, and by the test 

 of which I am willing that the scheme of classification and no- 

 menclature, above given in the Tabular View, should stand or fall. 

 That it will stand I have not the shadow of a doubt, so long as we 

 adhere to our geographical nomenclature. That it may be super- 

 seded, hereafter, by some more general and scientific classification 

 which may embrace the old and new world, and in which all 

 merely geographical and local names will disappear, is quite pos- 

 sible, and I trust probable : but such a speculation does not 

 come within the limited views of this paper. 



But now arises another question. Is there any other scheme of 

 classification and nomenclature which has a higher claim to our 

 acceptance ? The two, and only, " Lower Silurian " groups were 

 based on the evidence of a section above given {supra, fig. 5, 

 p. 313). When properly filled out and subdivided it becomes the 

 very section exhibited again and again before the Geological 

 Society of London during five or six years preceding the publica- 

 tion of the ^ Silurian System,' and in illustration of the Author's 

 scheme. It is virtually the same with the illustrative section 

 engraven on the original Silurian map. By myself it was accepted 

 for eight years (during which I never revisited the Silurian country) 

 with almost implicit faith and on the sole authority of the 

 Author : and I might almost say the same for all geologists who 

 had studied the palaeozoic rocks. 



But would geologists have accepted the "Lower Silurian ^^ 

 classification and nomenclature had they knowp that the phy- 



2K2 



