6 SKETCH OF THE GEOLOGY OF DERBYSHIRE. 
beyond it, giving evidence of a very great fault, which has suddenly 
depressed the whole of the first limestone and the lower part of the 
shale, and buried them out of sight to the S. of this fault. W. of 
this place, however, and over all the S.W. corner of the district, as 
well as in the limestone district of Staffordshire, no trace of the toad- 
stone has ever been detected. This circumstance is probably due to 
the absence of any considerable faults. All the S.W. portion of the 
limestone district has been so acted upon by the disturbing forces as 
rather to be bent and twisted into great ridges and hollows than ac- 
tually snapped asunder ; or where broken this, there has not been any 
great elevation or depression caused at the line of fault, so much as 
a change of dip or inclination of the beds. Even the Dove does not 
cut deeply into the limestone, as the beds dip, upon the whole, towards 
it on either hand ; and thus the first tendency to the formation of the 
valley was a downward curve of the limestone itself.* 
However great the apparent irregularity and confusion to which 
the faults give rise, it is found, on carefully tracing them out and lay- 
ing them down on a map, that they have themselves very great regu- 
larity, and evidently follow certain general laws. All the principal 
faults run for considerable distances, sometimes several miles, in di- 
rectly straight lines, and have others crossing them at right angles.t 
The one set in Derbyshire run N. and S. and the others, of course, 
E. and W. When a fault running from the S. in one direction is 
crossed by another at right angles, the angle of rock included between 
the two is frequently lifted up, with a steep face on either side; or 
when two faults running parallel to each other are crossed by another, 
the included piece is either elevated or depressed at the cross fault, 
and the other end affected in an opposite direction, and thus the piece 
made to sway, as it were, on a central axis. Priestcliff Lowe is an 
example of this latter case. A valley is frequently bounded by a 
fault on either hand, the two running parallel to each other; but it is 
very remarkable that these faults seldom coincide with the sides of 
the valley, but run at one or two hundred yards distance from it, the 
whole mass between them having been let down together, and thus, 
probably, a depression caused which gave the first tendency to the 
* The river frequently cuts through beds having the same dips on either 
side, but the position of the strata in the great mass of the hills I believe to 
be that mentioned in the text. 
+ For by far the greatest part of the information respecting the faults and 
veins of Derbyshire, I am indebted to Mr. Hopkins’s pamphlet before men- 
tioned. 
