190 MESSRS. KIEKBY AND DUFF ON THE 



complete instance of want of conformity between two formations. 



" The facts on which this conclusion rests are indicated in all 

 the quarries of the district, and in sections formed in various 

 coal- works which have been opened in the line of the limestone. 

 At Brussleton coal- works the average dip is about north by east. 

 In the Shildon works the dip is about N. by W. At the village 

 of Eldon the dip is nearly the same. At Coundon the Coal 

 Measures rise towards the limestone, and probably pass under 

 it. The dip of all the neighbouring coal strata is about N.N.W. 

 Lastly, at Ferry Hill, both the ancient and modern works are 

 sunk through the plateau of Magnesian Limestone, which has a 

 slight inclination to the S.E. After passing through about eight 

 fathoms of limestone they reach the Coal Measures, which dip 

 about N. by E. at a considerable angle. Beyond Ferry Hill the 

 coal strata decline more and more to the east, and gradually 

 acquire a dip which nearly conforms to that of the overlying 

 formation." 



Some obscurity exists as to the range of the coal-field beneath 

 the Permian and Triassic rocks in the south-west of the county. 

 Those collieries whose workings have extended the furthest 

 southward in that region, have found the strata rising sharply 

 to the south, and they have followed the coal-seams upward 

 until they ran against the unconformable Permian beds which 

 there overlie them. This has been observed at South Wingate, 

 Cornforth, and Thrislington. Various bores of greater or less 

 depth have been put down in the country beyond without prov- 

 ing the presence of Coal Measures ; though these bores cannot 

 in all cases be deemed satisfactory evidence of their absence. 

 When we consider what has already been described as to the 

 manner in which the coal-field ends in its south-west part, — 

 that is, by an outcrop to the south amid a series of large east 

 and west faults — we are disposed to think that all that is known 

 of the extreme south of the field to the eastward indicates a 

 continuation of the same manner of ending. 



That the change in the inclination of the Carboniferous strata, 

 noticed in the preceding remarks, is more than local is evident 

 from the persistence of a northerly dip on the Yorkshire side of 



