INTRODUCTION. Ixvii 
of the facts before the establishment of the May Hill group as the true Silurian base) 
—when it was adopted, almost to the letter, by the Government Survey—and when it was 
affirmed that the only workman, who had any claim against it, had abandoned his own 
work and thereby acknowledged himself wrong—the act of usurpation seemed for a time 
to be complete and triumphant. Any opposition to it was a philosophic heresy, and any 
word raised against it was received by the Geological Society of London with absolute 
mockery and misplaced scorn. 
A conquest made in war, whether just or unjust, may be long upheld by the same 
brute force which gained it. But it is far otherwise in the more honest and peaceful 
conflicts of natural science. Science is a republic which admits of no dictation but from 
truth and reason; and from them there is no appeal. 
If in the progress of a rapidly advancing science a great and good workman make a 
great mistake; and if that mistake be largely adopted under the sanction of his name; so much 
the worse for himself. Physical truth is not a thing mutable and dependent on popular 
voice. The truths of nature are eternal. Physical mistakes (whether of classification and 
nomenclature, or of a false induction from facts imperfectly observed,) may last their day : 
but that day cannot be long, while the spirit of enquiry is alive among mankind, and they 
are awake to the power and sanctity of philosophic truth. Magna est veritas et prevalebit, 
is a trite old saying; but it will be true so long as there is constancy in nature. 
There never ought to have been any controversy between the author of the “Silurian 
System” and myself. Our work was sufficiently distinct to allow each of us his own pro- 
vince, even while a large border country remained in doubt, and was open to a double 
claim. But he contrived from the first (casting the consequences of his own mistakes upon 
myself) to make it a very ungenerous controversy; by excluding my hard and long-con- 
tinued work, which was substantially right, from all name and notice; and claiming by 
despotic title a country over which he had gained no rightful conquest, many parts of 
which he had never touched; with which, when his scheme of absorption was first pub- 
lished, he was very imperfectly acquainted; and which, even now, he only knows well at 
second ‘hand. Since the establishment of the May Hill Sandstone as the physical and 
paleontological base of the Silurian rocks, we have, at length, a well-defined separation 
between Cambria and Siluria; and there is no longer any equitable or reasonable ground 
of controversy on the score of classification and nomenclature. If it be continued now, it 
is nothing more or less than a useless struggle for the perpetuation of a positive wrong. 
It might seem incredible that a scheme of classification which involved the gross geo- 
graphical absurdity of absorbing Cambria into Siluria, and the palpable geological absurdity 
of making the Cambrian Series of the Tabular View the equivalent of the Llandeilo Flag, 
could set up its claims for our permanent acceptance. But moral arguments have been 
advanced I think unfairly, which if true would put me greatly in the wrong: and I believe 
that such arguments have had more weight with some English geologists than those which 
were physical. 
42 
