INTRODUCTION. Ixiii 
above the Bala group. But a system his groups were called. Here was the first mistake. 
A yerbal mistake may, and often does, become the foundation of an unconscious sophism. 
Following in this train, the oldest fossil-bearing rocks of Russia were called Silurian. 
They were identified with the “Silurian System*.” But the author afterwards found among 
the Cambrian mountains (of the Bala group) the rocks he had called Silurian in Russia. There- 
fore the Cambrian mountains (all the groups, in short, of the Cambrian series in the Tabular 
View) were to be Silurian! And as such he mapped them (in 1843) without a syllable of 
communication to myself. If we admit the Silurian syllogism advanced in the concluding 
words of a preceding page (supra, p.56), we must accept the consequence of this new syllogism. 
It is irresistible. Yet from the very starting-point of the author’s reasoning there lurks both 
a mistake on a point of fact, and a virtual sophism. The Silurian sections were not true; 
and had the groups (down to the Llandeilo Flag) been truly placed, they did not form a 
System, as he interpreted their relations when he illogically grouped them into “a System.” 
I think it evident that the author of “the Silurian System” suspected that his lower 
sections were erroneous before he altered the colours of his map in 1843. He may also 
have suspected that my upper Cambrian sections were in principle erroneous; and if so, he 
was mistaken. But on no conceivable supposition could he have a right to mask his own 
mistake by a spoliation on the scientific property of his fellow-labourer. Had he been 
playing a solitary game he might have shifted the cards as he pleased: but the game was not 
solitary. I had done the hard work in Cambria. Of Cambria he had only touched the out- 
skirts, which he certainly had misinterpreted at the time he published his System and defined 
its base. Small reason, therefore, had he (except the despot’s plea) to readjust his boundary 
at my cost, to extrude me from the country over which I had the right of conquest, and to 
claim it as his own. Had his lower groups been right they would have sanctioned no 
claim beyond a share in the Bala (or Upper Cambrian) group: but that claim is now 
at an end by the establishment of the true Silurian base—the May Hill Sandstone. Had the 
extended Silurian nomenclature been more symmetrical, and geographically more true than 
mine, it might have had some claim in point of taste: but geographically it is incongruous 
to the last degree. The rocks of Cambria are no longer to be called Cambrian, but they 
are to be called Silurian, to give a stability to the so-called “Silurian System,” which 
without their help is baseless! 
But it may well be asked, if such were the facts of the case, how came geologists 
so generally to accept the Silurian nomenclature in its widest and most illogical extension ? 
* Let no one say that my objections to the extended use of the words “Silurian System” were an afterthought. 
When the magnificent work done by my friend and his fellow-labourers in Russia was first expounded to the Geological 
Society, I took an objection to the name “Silurian System” as applied, without qualification, to the older rocks of 
Russia. My objection was ill-received by those who knew nothing of its true meaning. The author of the 
Silurian System saw, I cannot doubt, the direction in which his scheme of nomenclature was drifting. I at least 
saw yery plainly that it involved, as its logical consequence, the incorporation of nearly all North Wales into the 
Silurian System. My objection was not therefore captious and frivolous, as was supposed and asserted by some 
who knew little of the true development of the older Palozoic rocks of Britain. It was only a vindication of first 
principles which ought never to have been abandoned. 
