506 Prof. Sedgwick on the May Hill Sandstone, ^c. 



Murchison borrowed from me, or took on my authority, his 

 views respecting the relation of his Lower Silurian groups to the 

 Upper Cambrian system, is so directly contrary to fact, that I can 

 only oppose it by a direct denial. But I by no means accuse Mr. 

 Sharpe of intentionally misrepresenting me. I have often spoken 

 of the great Upper Cambrian groups of South Wales as inferior 

 to the Silurian system ; but on what authority ? On the sole 

 authority of the Lower Silurian sections, and of the author's many 

 times repeated explanations of them before they were published. 

 So great was my confidence in his work, that I received it 

 as a perfectly established truth that his order of superposition 

 was unassailable. Not one atom of blame, touching this ques- 

 tion, can rest upon me. I never gave advice about it, and I 

 never was consulted upon it. I accepted his order of superpo- 

 sition and clung to it, and never doubted of its truth, till in 

 1842 I had followed it into one of its remote consequences; 

 and then found that it could not be true, because it involved in 

 its consequences a palpable contradiction. 



I asserted again and again that the Bala limestone was near 

 the base of the so-called Upper Cambrian group. Sir R. L 

 Murchison asserted, and illustrated by sections, the unvarying 

 fact that his Llandeilo flag was superior to the same Upper 

 Cambrian group. There was no difference between us till his 

 Llandeilo sections were proved to be wrong. But I need not 

 dwell on a point that cannot, I trust, be disputed, as it would at 

 length involve a direct question of truth and falsehood. 



The author of the ' Silurian System ' cannot have overlooked 

 the passage last quoted, and he ought not to have allowed it to 

 pass unnoticed, in the comment on Mr. Sharpens paper, which 

 appeared in his next anniversary address. It is not always easy 

 to comprehend an author's meaning ; but there are some pass- 

 ages in the recent work ' Siluria,' which an ordinary reader 

 would, I think, misinterpret, and so construe as to infer that in 

 describing the Cambrian groups I had misled the author of the 

 ' Silurian System.' I did not mislead him, unless it were by im- 

 plicitly adopting his views and believing in his sections. The 

 " System " is before the world. Its groups are all his own ; and 

 if he mistook the relations of his lowest group, and thereby put 

 a drag (as assuredly he did for several years) upon the progress 

 of geology, he has honour and strength enough to bear this 

 blame ; and it would ill-become him to throw one particle of it 

 on the shoulders of his old friend and former fellow-labourer*. 



* There are some sentences which I greatly object to in the recent 

 work, "Siluria" (Chap. i. pp. 7-9). They do not state the whole truth; 

 and without some comment, they naturally lead to a conclusion which is 

 not historically true. They will, I trust, be set right in the next edition. 



