444 A Reply to Mr, Carr's Letter, 



these two points, nay all their operations have been founded 

 upon them, from the earliest periods in the practice of their 

 arts : but unfortunately, with some rare exceptions, such 

 have confined their researches to their own particular fields 

 or to very limited districts round them, and have loo often 

 satisfied themselves, with the most vague and unsatisfactory 

 guesses, at the identity of the particular strata worked By the 

 miners in other districts, even of those which adjoin, in nu- 

 merous instances : and I am sorry to add, that after visiting 

 more than .200 collieries between Nottingham and this place, 

 and conversing with the owners or workmen or both, upon 

 jnost of them, I have not been able yet to discover any two 

 whose ideas are perfectly consistent with each other, as to 

 the identity or otherwise, of the coal and ironstone working 

 in places distant from their own works : my confidence, 

 however, increases daily, of being able (should health and 

 prudential considerations admit of a sufficient application 

 of time to the subject) to reconcile all the facts 1 have col- 

 lected, to the satisfaction of this great body of practical men, 

 and to scientific inquirers in general. The zeal which X 

 feel, for stimulating others, better qualified than myself, to 

 enter on and pursue similar and even more minute inquiries 

 in this or other districts, than I have been able to accomplish 

 or attempt, has however here led me beyond what I in- 

 tended at present: and I return to page 385 of your last 

 Number, in order to notice the opinion advanced by Mr. 

 Carr, that ie solely from the superior durability of its ma- 

 terials, which have withstood the operation of those tre- 

 mendous agents that have swept away the surrounding 

 country/' are we to look for the cause of an isolated moun- 

 tain composed of successive piles of strata i in order, on a 

 point of so much moment to mention, that though a grit- 

 stone rock very often occupies the very summits of hills in 

 the coal districts, yet that such are generally , too soft and 

 their blocks adhere too slightly, to admit of our referring 

 the form of the \\\\\ solely to the resistance these rocks offered 

 either to a violent action of gravity from above, (as I have 

 supposed,) or to the sudden or even to the long-continued 

 action of " water/' moving oyer the surface according to 



