INTRODUCTION. lix 
the assumed integrity of the sections, to persevere in it (when the sections were proved 
untrue), out of deference to the author of the System, and out of regard to his great 
services? Any one who can give a positive reply to such questions is out of the reach of 
argument; and has but a low conception of the true dignity of physical science, and the 
sanctity of philosophic truth. 
When the author (in 1842) examined—I believe for the first time—the Cambrian 
Series of North Wales along with his Russian fellow-labourer Count Keyserling, he found, 
among the Cambrian groups, the fossils he had called Lower Silurian; and the very rocks 
he had taught his Russian friends to designate by that name. But, so far as regarded the 
fossils, was this a new discovery? It was no such thing. It was but the lesson I had put 
before him, and which he had read correctly, when we visited the Bala rocks together in 
1834. There was no shade of difference in the fossil evidence. But in 1854 the Bala group 
was to be called Cambrian; because it was deep-seated in a group which he (by mistake) 
had placed below his Llandeilo flag:—while in 1842 the same Bala group and other 
Cambrian rocks were to be called Silurian; because he had called the Russian rocks of the 
same age Silurian! This proves, I think, to demonstration, that the author had no right 
whatever to the nomenclature he gave to the rocks of Russia; and that a deep injury may 
be inflicted on the cause of scientific truth by a precocious classification and nomenclature. 
That the author (in 1839) doubted about his base line, is evident from a single 
paragraph near the end of his great work—* The Silurian System.” But if there were any 
paleontological, or other grounds of doubt, the nomenclature and the classification were, so 
far, in abeyance; and as there were two labourers in the field, the natural question (if any 
doubts arose) seemed to be, who was in the right, or who was in the wrong? Yet this very 
natural question never seems to have crossed the mind of the author of Siluria, except 
in an erroneous and one-sided form. His only doubt was whether he might not enclose, at 
some future day, a part of Cambria within his boundary. But surely there was another doubt, 
whether (if his Lower Silurian sections proved wrong) he might not have to contract his 
Silurian base to some position that was more compatible with physical and fossil evidence. 
While these doubts remained, it seemed but reasonable to establish a middle group, with a 
name that should recognize the joint labours of the author of “Siluria” and of myself. Had 
this concession been made the author would have gained by it more than was his due ; for 
his true Silurian base is the May Hill sandstone, and nature has given him no other. 
But concession was far from his thoughts. He had given (without any true claim based 
on his own sections or on his knowledge of the older rocks of England) the name “ Lower 
Silurian” to the oldest Palaeozoic rocks of Russia. When he afterwards examined the Cam- 
brian rocks of England he must have known, or at least suspected, that his typical Lower 
Silurian sections were wrong. Did he then attempt to qualify his Russian nomenclature / 
No such thing. Dazzled, it seems, by the well-earned honours he had gained in Russia, he 
could not see the false position in which he stood among the older rocks of England: 
nor had he ever the magnanimity to acknowledge himself wrong on one single point. 
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