MURCHISON ON THE SILURIAN SYSTEM. 183 



names had been applied to that which is ascertained to be one natural 

 system, great disservice would have been done to geological science. 



I am now well pleased to find, that, with the exception of my 

 old friend, all my geological contemporaries in my own country 

 adhere to the unity of the Silurian System, and thus sustain its gene- 

 ral adoption. In fact, they know that the proposed application of the 

 word "Cambrian" must necessarily cause an alteration of a funda- 

 mental character in the nomenclature used in every memoir and work 

 on rocks of this age during the last ten or eleven years ; for the Lower 

 Silurian rocks of North Wales so described by Sharpe, Phillips, 

 Davis, and Ramsay, and, finally, so styled in all the Government 

 works by Sir H. De la Beche, — the Lower Silurian of Ireland so 

 named, mapped, and illustrated by Grifiith, Portlock, and M'Coy, — 

 and the Lower Silurian of Scotland so expounded and illustrated by 

 Moore, Nicol, Harkness, Salter, and myself — must, according to Pro- 

 fessor Sedgwick's project, be changed to Cambrian. Again, the British 

 writers on general geology, Lyell, De la Beche, Mantell, Ansted, as 

 well as E. Forbes and all palaeontologists, must alter the names and 

 arrangements they have adopted. 



Still more striking would be the revolution as respects foreign 

 countries ; for, as Russia, France, Spain, and other regions offer only 

 very slight traces of the Upper Silurian, the System must virtually be 

 there expunged, and the word Cambrian be substituted in all works 

 and maps. The elaborate and valuable monograph of Barrande, ' The 

 Silurian Basin of Bohemia,' must not only have a fresh name, but the 

 whole principle of classification of that able writer, who distinctly 

 afiirms that it is one great system of life as of rocks, must also be 

 changed ; whilst in America the " system " which Hall and others, 

 have so well paralleled with the "Silurian," and the writings and 

 maps of Logan on the Canadas, must all be re-cast and re-named. 



I may here say, that I was never so truly gratified as when my 

 contemporary brother workmen (my old friend Professor Sedgwick 

 being one of them) united in recommending me as worthy of the 

 highest British scientific honour ; and I specially recur to this point, 

 because the Copley Medal of the Royal Society was bestowed on 

 me in the year 1849, not merely for the publication of the Silurian 

 System of 1838, but also /or its subsequent and extended application 

 to other countries^ . 



No one more regrets than myself that Cambria should not have 

 proved what it was formerly supposed to be, more ancient than the 

 Silurian region, and thus have afforded distinct fossils and a separate 

 system ; but, as things which are synonymous cannot have separate 

 names, there is no doubt that, according to the laws of scientific 

 literature, the term " Silurian " must be sustained, as applied to all 

 the fossiliferous rocks of North Wales. 



Lastly, let me say to those who do not understand the nature of 

 the social union of the Members of the Geological Society, that the 



* The terras in which the Copley Medal was awarded in 1849 are — " For the 

 eminent services he has rendered to geological science, and for his works, ' The 

 Silurian System ' and ' The Geology of Russia and the Ural Mountains '." 



