108 The Cambrian and 



elusion. Had the author (when he found that his fundamental 

 sections were wrong) contracted his system, and based it on the 

 Caradoc group, which seems to he a natural connecting link be- 

 tween the true Silurian and the true Cambrian groups, he might 

 have continued his nomenclature, and maintained it in its true 

 integrity. For the several groups of his system would then have 

 been well defined " by the order of superposition and imbedded 

 organic remains" seen in a series of true typical sections ; and the 

 collective groups of his system might have been very properly 

 called Silurian, " to mark thereby (using his own words) the 

 territory in which the best types and clearest relations were ex- 

 hibited." 



But in 1843 my friend applied a new principle of nomen- 

 clature to a great series of Cambrian rocks which he had never 

 examined, and of which I had first determined the true general 

 relations. They were to be called and coloured as Silurian, be- 

 cause they contained certain fossils common to the beds he had 

 called Lower Silurian, yet of which he had, in his fundamental 

 sections, misrepresented the relations. This principle I have a 

 right to call new, for it was in direct antagonism with his con- 

 clusions in 1834, when we were together in the field. It was not 

 enunciated in the " Silurian System ;" it was not acknowledged, 

 but rather contradicted, by what I had myself written, and it was 

 never communicated to myself. I was no consenting party to the 

 colours placed by my friend on a geological map of England in 

 1843 ; nor did I even know of its existence till two or three years 

 afterwards. We may apply this principle with safety, if it be 

 derived from an old system which has been perfectly defined, and 

 of which the several subordinate parts have been already named ; 

 but as applied to a new and unknown system, such as that of 

 Wales, it virtually destroyed the sense and meaning of the whole 

 Silurian nomenclature, for it deserted the principles the author 

 himself enunciated for his own guidance and the vindication of 

 his adopted names. Palaeontology is not the mistress but the 

 handmaid of geology ; and any new system, drawn from an 

 unexplored country, is utterly worthless if it rest not funda- 

 mentally on the evidence of natural sections and natural groups. 

 Fossil evidence may then follow, but it tells us nothing in a new 

 system while the groups are undefined. 



Out of all comparison the greatest boon, within my memory, 

 conferred on palaeozoic geology was the establishment of the Upper 

 Silurian groups. The honour derived from this great boon is my 

 friend's undisputed right. The establishment of the Devonian 

 series soon followed by an almost inevitable necessity. We had 

 long known, through many published works, the general aspect 

 of Hie older palaeozoic fauna ; and when the Devonian and Upper 



