INTRODUCTION. Ixxxv 
incapable of arguing with him. For in that case we must differ in those first principles 
of inductive reasoning, without an agreement in which all rational argument is impossible. 
To conclude the whole discussion:—the author of “Siluria” has not improved, but 
greatly weakened, his own position by his new Volume. While he argued from fossils only, 
he might keep out of sight the positive mistakes of his early sections; and he might contend, 
with some show of reason, that the fossiliferous Cambrian strata must be called Silurian 
because they contained the fossils he had described and called Silurian. But he was well aware 
that the argument thus stated implied a desertion of his first principles of nomenclature : and 
he has at length attempted to vindicate his scheme of nomenclature and classification by 
the help of sections—by physical as well as by fossil evidence. With something which 
appears to me like a blinking of the facts, and like a deception of the reader by a palpable 
sophism, he has put forth a section as a Cambrian prototype, though entitled to that 
name neither geologically nor historically. And because he had (by a palpable inconsistency 
of nomenclature) called some of its older groups Silurian; therefore—discarding his original 
Silurian types—the older Cambrian equivalents of such groups must also become Silurian! 
Thus, whether he argues on paleontological or physical grounds, he proceeds, at once and 
despotically, to turn his own mistakes to positive profit. But this can never last, while we 
have a true geographical nomenclature, honestly worked out by the help of true sections, and a 
real prototype, which deserves its name physically as well as chronologically. My classification 
and nomenclature are true, if there be truth and consistency in the principles of Geology. 
They have the right of historical priority, and ought never to have been tampered with; 
and when the controversy began they were tampered with in great ignorance of the real 
structure of the older Paleozoic rocks of Wales, and consequently of the real merits of 
the question in debate. There is, now, I repeat, no legitimate ground of contest between 
Cambria and Siluria; they are separated from one another by Nature’s own boundary line; 
and the attempt to confound them is only the vindication of a preposterous wrong by a 
pretended right of usurpation. The republic of Science refuses, and to write without a 
figure—which is far better—common sense and reason refuse, to sanction this usurpation. 
I subjoin the following note to introduce some references which ought to have been made 
in the preceding pages of the Introduction*. 
* The reader is requested to bear in mind that the original Silurian descending order was as follows: Ludlow, Wenlock, 
Caradoc, and Llandeilo; below which came the Cambrian rocks. On this scheme, all the typical Silurian Sections, the 
Silurian nomenclature, and the Silurian map, were constructed: and all my collective upper Cambrian groups (whether in 
Merionethshire, or, spread out in multitudinous undulations, in Radnorshire and Caermarthenshire) were placed by the 
author of the “ Silurian System” below the Llandeilo group. There was no doubt ever expressed by him as to the reality 
of this order. Nor was it supposed that there was any very great break of continuity in the descending sections: for he 
affirmed that in several places there was an ascending passage from the highest upper Cambrian strata into the beds at the 
base of the Llandeilo group (“Silurian System,” p. 357 to p. 363). Such was the scheme—adopted by its author, before I 
saw the typical Silurian sections in 1834, formally repeated in 1836, and more formally published and vindicated in 1839. 
In confirmation of what has been just stated, I will now appeal to some passages in the “Silurian System” which 
Thad not the means of quoting when the latter pages of the Introduction were sent to the press. At p. 356 are the 
following words. “The Griig quarries (about three-quarters of a mile north-west of Llandeilo) exbibit the oldest calea- 
