46 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June S, 



ignorant), and that rocks with peculiar fossils should be pointed 

 out in lower positions than any of those charged with Lower Silurian 

 forms, and reposing on still lower strata — or lastly, if Sir Henry De 

 la Beche and his coadjutors, who are now subjecting North Wales 

 to a rigorous survey, shall assure me that there is a distinct fossili- 

 ferous system beneath that which they have honoured me by term- 

 ing "Lower Silurian," then I hope I have sufficient candour to 

 modify my views according to such evidence and render them sub* 

 servient to the advancement of Geological science. But supported 

 by the fossil proofs and the order of superposition derived from in- 

 vestigations in Europe and America, and by the opinions of all those 

 paleeontologists with whom I have acted (including Mr. James 

 Sowerby and M. de Verneuil), I adhere at present firmly to my 

 classification, founded on original researches in Siluria. 



The additional matter supplied in this memoir will, I trust, at all 

 events be taken as affording the clearest evidence, that in Scandina^ 

 via the Lower and Upper groups are well-defined by the same divi- 

 sional lines as those originally proposed by me for the classification 

 of these deposits ; for he who would attempt to rob the Wenlock 

 formation of Gothland of one of its members, in order to include it 

 in the Lower Silurian group of those countries, would most certainly 

 be opposed by every geologist who had ever seen either the country 

 or the fossils. 



Again referring my readers to the first three chapters in the work on 

 Russia and to my former Memoir on Scandinavia, as well as to the 

 comparative tables then and now published, I leave this subject to 

 the consideration and decision of geologists, merely expressing my 

 hope, that the classification of Lower and Upper Silurian may not 

 be put aside or obscured, so long as the order of succession and 

 zoological evidence sustain it. My aim during the last few years 

 has been, not to dwell upon the peculiar development and details of 

 the sections in North Wales ; for that ground is in the course of survey 

 by several Government geologists, who will accurately determine the 

 dimensions of such strata and all their physical and zoological fea- 

 tures. My chief objects, on the contrary, have been, to ascertain on 

 a great scale, whether the lowest stage containing vestiges of life in 

 other parts of Europe v/as or was not zoologically the same as the 

 Lower Silurian of myovi^n country, and whether it was there, as in En- 

 gland, succeeded in ascending order by another member of the same 

 natural system of deposits which 1 had termed Upper Silurian. The 

 Silurian system, so defined, has been shown to be successively sur- 

 mounted, over wide tracts, by the Devonian, Carboniferous and 

 Permian systems, thus completing the history of palaeozoic succession 

 in Northern Europe. 



