VARIOUS DIRECTIONS OF THE CHAINS. 



267 



striking deviations from parallelism, even in those cases in which the strata affected are 

 of the same age, and on the other hand, coincidences of parallelism between rocks formed 

 at different epochs. For example, in Haughmond and Lyth Hills, where the sedimentary- 

 deposits affected are the Upper Cambrian or oldest treated of in this work, the strike 

 is from north-east to south-west, or parallel to the axis of the Silurian Rocks, whilst 

 near Pontesford Hill, where the strata are mere continuations of those of Lyth and 

 Haughmond and throughout theLongmynd and Linley Hills 1 , the strike is N.N.E. and 

 S.S.W.; being a variation of 25° in the direction of the same beds in a distance of a few 

 miles. A similar direction to the N.N.E. is observed in the Lower Silurian rocks of the 

 mining region of Shelve and Corndon, whilst in the Breidden Hills, the strata being of 

 the same age, the strike is E.N.E. and W.S.W., making a diversity of 50° between two 

 contiguous lines of eruption. (See the Map.) In all these cases the strata belong to the 

 Cambrian and Silurian Systems, and some of the youngest members of the latter are by 

 reversed dips and renewed anticlinal lines repeatedly brought to day far to the westward 

 of their principal line of bearing in Salop, Hereford, Radnor, Brecknock, and Caermar- 

 then, as will be explained in the following chapters. 



The stratified rocks described in this chapter (Longmynd, &c.) are lithologically 

 similar to, and probably of the same geological age as the so-called greywacke of the 

 Lammermuir and other hills in the south of Scotland. They may also be placed in 

 parallel with much of the greywacke of the north of Ireland, and with that of large 

 tracts in Somerset and Devon. 



1 The strike of the Longmynd (N.N.E. and S.S.W.) is parallel to that of the Cambrian Rocks of North 

 Wales. 



