A. 8irahan's Address to Section 0, Geology. 453 



known to be partly of Triassic but principally of Carboniferous age. 

 In the course of the investigation we shall find reason to conclude 

 that several at least of the movements followed old axes of 

 disturbance, lines of weakness dating from an early period in the 

 history of the habitable globe ; and, again, that some of the latest 

 disturbances of which, we have cognisance were but renewals of 

 movement along the same general lines. 



One of the most clearly proved examples of pre-Permian faulting 

 in the Carboniferous rocks occurs in the Whitehaven Coalfield. The 

 fault forms the south-eastern limit of the Coal-measures, and has 

 been precisely located for a distance of six miles. In its course 

 towards the south-west it passes under five outliers of Permian 

 rocks, and finally is lost to sight under the Permian and Trias 

 of St. Bees. The dislocation in the Carboniferous rooks amounts 

 to about 400 yards, but the Permian rocks have not been even 

 cracked ; though broken and displaced by numerous faults of 

 later date, they pass undisturbed over this great dislocation, the 

 movement along it obviously having ceased before they were 

 deposited. This fault forms part of the upheaval which brought 

 the older rocks of Cumberland and Westmoreland to the surface, 

 and in that sense it may be said to form the north-western frontier 

 of the Lake District. 



On the north-eastern side also of the Lake District the Permian 

 rooks rest upon uptilted Carboniferous strata, but the axis of up- 

 heaval runs in a north-north-westerly direction and defines what 

 we may regard as the north-eastern frontier. Along this frontier 

 much movement has taken place in post-Permian times, but the 

 unconformable relations of the Permian and Carboniferous rocks 

 enable us to distinguish that part of the tilting which intervened 

 between the two periods. On the south-eastern frontier also the 

 Carboniferous rocks had been upheaved and denuded before the 

 Permian sandstones were laid down. A huge fault, along which 

 Carboniferous rocks have been jammed from the east in a multitude 

 of plications against Silurian, runs from Kirkby Stephen by Dent 

 to Kirkby Lonsdale, and thence trends south-eastwards by Settle. 

 It is highly probable, though it has not been proved, that this 

 fault is of pre-Permian age. That the Pendle axis which upheaves 

 the Lower Carboniferous rocks between Settle and Burnley is 

 pre-Permian is placed beyond doubt by the fact that an outlier of 

 Permian rests upon the denuded crest of the anticline near Clitheroe. 



The south-western frontier is defined by a still more marked 

 unconformable overlap by the Permian strata, which here pass 

 over the edges of the lowest members of the Carboniferous series 

 and come to rest upon the Lake District rocks. 



We have thus defined the sides of an oblong tract which was 

 upheaved in the period we are considering. The older rocks 

 forming the northern part of that tract had already had imposed 

 upon them a dominant north-easterly strike by a pre-Carboniferous 

 movement of great energy. As a result also of that and other 

 movements they had been subjected to vast denudation, not only 



