122 Mr. Hopkins's Remarks on Farey's Account of the 



I have now so fully satisfied myself of the entire erroneousness 

 of Farey's views of its stratification, I will, with your permis- 

 sion, enter with some detail into a refutation of them. 



Before I notice those points on which Farey and myself 

 differ so widely, I will mention one in which we are entirely 

 agreed, viz. the regular interstratification of the toadstone 

 with the limestone. The direct evidence of this is afforded 

 by those cliffs in which the fact is matter of observation ; and 

 the indirect evidence of it must be sought in the circumstance 

 of our being able to found on this hypothesis a generalization 

 which shall clearly and distinctly embrace all the particular 

 phenomena which the stratification of the district presents to 

 us. The validity of this latter evidence must, of course, de- 

 pend on that which can be offered in proof of the generaliza- 

 tion contended for; but as the examination of this evidence 

 would necessarily involve the complete discussion of the sub- 

 ject, into which it is far from my intention to enter at present, 

 I must content myself with stating my conviction of the fact 

 of this interstratification of the toadstone. Any opinion of its 

 unconformability with the limestone beds, professing to rely 

 upon observation, can only, I think, be founded on a superficial 

 examination or on an imperfect conception of the subject. I 

 mention my conviction on this point more particularly in conse- 

 quence of Mr. Conybeare's having suggested, in the paper 

 above alluded to, the possible unconformability of the toad- 

 stone, from its having, perhaps, been thrust up among the 

 limestone beds at a period posterior to their formation. In 

 addition, however, to the reasons above mentioned, I conceive 

 that any such idea must be completely negatived by the total 

 absence of all indications of that mechanical violence which 

 must necessarily attend the forcible intrusion of a mass of ig- 

 neous rock among masses previously deposited. 



1 will proceed, however, to the exposition of what I con- 

 ceive to be erroneous in Farey's account of the district. 



He has asserted (and it should be recollected that on this 

 subject he has made many assertions, but has given no 

 proofs,) that there exist in the limestone district of Derbyshire 

 three distinct beds of toadstone. The limestone occupying the 

 surface, and lying above the first or highest toadstone — that 

 between the first and second toadstones — that between the 

 second and third — and that beneath the third — he has termed 

 respectively theirs/, second, third, and fourth limestones. He 

 states that these beds of toadstone have continuous bassets, 

 that of the third or lowest bed commencing on the north near 

 Castleton, and ranging by Wormhill, Chalmerton, Pike Hall, 

 and the Grange to Bonsai Dale ; and those of the two other 



