Mr. Farey's Account , &c. 243 
from off the Wealds of Kent, Sussex, and Surry, and had ex- 
plained to you, by a rough section across this great southern 
denudation in 1806, and such as the valley of Ashover then 
appeared to present, a more perfect instance of, around us : 
but that previously to such denudations of the Derbyshire 
strata, immense dislocations or vertical derangements of very 
large piles of strata, separated by the fissures, called faults by 
the miners, needed also to be taken into account, for explain- 
ing the appearances of the strata and surface of the district, 
which I was then about to explore : faults, exceeding im- 
mensely in their extent and quantity of lift on one side (or 
sink on the other) any which had occurred to Mr. Smith, in 
the tracing of the .south-eastern strata of England, where no 
faults had been discovered, so considerable as to cut off en- 
tirely the connection of the strata, or in other words, to bring 
strata in contact on the surface, whose places in the series 
were too distant to be known, and readily traced in their order, 
in the neighbourhood. And in consequence, I judged it ne- 
cessary, on my return to town, when the winter arrived, to 
set about the consideration of stratified masses, broken and 
dislocated, and then cut or denudated in all the variety of cases 
and degrees of each, the results of which investigation, will 
appear in my Report to the Board of Agriculture on Derby- 
shire, the first volume of which is now in the press. 
With ideas thus extended, I found, on resuming my Survey 
in the spring of 1808, that some conclusions that I had formed, 
and had unfortunately committed to paper, in a sketch of a 
section across the county, were erroneous, and that immense 
faults occurred, in places where their existence had not been 
proved by miners, or generally understood, which combined 
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