110 © Mr. Silverwood’s Section of Derlyshire Strata. 
doing, by an actual Jevelling over the surface, and ascertain- 
ment of the top and bottom of each Rock or visible stra-- 
tum, and its dip, to be applied to the thicknesses previously ’ 
ascertained by sinkings; a Map of the surface of the strata, 
on the same scale as the lengths and depths, will also I hope 
be annexed to it, as is mentioned of my Ashover great 
Section of 7 miles in length, in my Ist Letter. Such a 
Section continued from the top of the lower yellow Lime 
to the 4th Lime would be about 16 Miles long, if it com- 
menced on the S of Annesley and terminated in Bonsal- 
dale, S of Slaley; through 10 Miles of which distance, a 
Jevel pound of the Cromford Canal being at hand, might 
greaily shorten the labour of, as well as give great accuracy 
to the levelling, and the very curious denudation at Golden 
Valley (Rep. 1. 164 and xlvi.) and the southern skirt of 
that at Crich, would be intersected and shown thereby. 
T sincerely hope that this important work may soon be 
completed by Mr. Silverwood ; and as soon as I hear that 
the eastern part of it is finished, 1 certainly will, at the 
first opportunity of travelling that way, avail myself of the 
kind invitation I have had from the resident proprietor’ 
Nathaniel Edwards, Esq. to see Mr. S’s Sinking account 
and Section ; and if possible, I will trace the zigzag fault’ 
across it. At the present time, it appears to me, that Mr. 
B. has rather expressed his wishes than his knowledge, as 
to Mr. S’s decision on my Fault, in his Note from whence 
I have extracted as above. 
At the time that I entered on my Survey of the neigh- 
bourhood of Greasley in Nottinghamshire, the extended 
fracture of the strata which I have since denominated the 
zigzag fault, was unknown to every one, as I have men- 
tioned, Rep. i. 162; I was neither surprised or displeased 
therefore, that the practical Men seemed then averse to 
admit it, some perhaps because it was their interest not to 
admit, that their Coal had a different place in the series, 
as to identity with those of other works in more repute with 
the buyers, than that which prevailing opinions had pre- 
viously assigned it. 
On the 13th of October 1808, I had the honour to be 
invited to dine at a Meeting of the Coal-masters held at 
Eastwood, at which 12 or 14 Coal- masters, or their Agents, 
from a! the principal works around were present; after the 
business of the meeting was concluded, and dinner was 
over, two or three hours were spent, principally in dis- 
cussing this novel explanation of the facts of their Coal 
strata, and in which I certainly found myself quite alone in 
; opinion. 
