An Account of the Great Derby sidre Denudation. 3 1 



the east side, under the gravel, Sec. from near Nottingham 

 to near Welherbv in Yorkshire. From Lenton E. of Not- 

 tingham, to Alleslry N. ot Derby, the upper parts of the 

 coal-me.^sures in the first raised tract, abut onAhe red n)ar! ; 

 here another great f'auh, called the zig-zag fault, intersects 

 the boundary fault: from AUestry.to the S.E. corner of the 

 Weaver Hills near Wooion in SlafTordshire, the second 

 inner irjct, with a vastly greater rise than the first, abuts on 

 this southern fault, so as to bring the great limetone- shale 

 (which underlays all the coal-measures) against the red 

 marl on the surface; at this S.E. corner of the Weaver 

 Hills, another great fault (called the great limestone fault) 

 intersects the southern boundary (or great Derbyshire) fault 

 of the raised tract ; and from this place to the S.W. corner 

 of the Weaver Hills near Ranisor, a third inner tract, with 

 four hundred yards or n)ore of perpendicular rise, in addi- 

 tion to the last, occasions the fourth, or lowest limestone 

 rock, to abut against, and even make a high hill above the 

 red marl at the foot of it, on the other side of the great 

 Derbyshire fault ; which here occasions a sudden derange- 

 ment of the strata (and a correspondins denudation of the 

 large tract of country to the northward has taken place), 

 far exceeding any thing which has hitherto been mentioned 

 bv authors, or conceived probably bv any one. 



At the S.W. corner of the Weaver Hills above men- 

 tioned, the great limestone fault again leaves the south 

 boundary, or great Derbyshire fault, and proceeds north- 

 ward, after which a corner of the second interior raised tract 

 aeain presents itself, and the limestone-shale a2;ain abuts 

 on the marl, as we pursue the great Derbyshire fault to the 

 v/estvvard, owing to the rise beine less here by four or five 

 hundred yards, than it was in the third interior tract ; hut 

 as we proceed southwestaard, owing to the dip of the 

 measures on the N. side of the great Derbyshire fault to- 

 wards the west, the first grit, the first coal-sliale, and the 

 second grit rock successively abut against the marl, before 

 the gravel covering commences, east and south of Cheadle, 

 which prevented my tracing this fault any further, within 

 the limits of my Survey. 



It seems probable, however, that somewhere S.W. of 

 Cheadle in Staffordshire, a braiich sets off" from the great 

 Derbyshire fault, or souihern boundary of the lifted tracts, 

 and proceeds northward, near to Endon and Bosley in 

 Cheshire ; the triangular tract beyond which, to the west- 

 ward, shown in the map, forming the pottery coal-field, is 



niucli 



