290 



THE BREIDDEN HILLS. 



these calcareous beds and the grey granular felspar rock. These impure limestones belong to the 

 Caradoc formation, and will be further described in the ensuing chapter. 



A very hard;, heavy, and much altered rock, has been recently laid open on the western side in 

 improving the road to Guilsfield, some portions of which are with difficulty distinguished from 

 the trap itself. The general aspect, however, and above all its possessing the character of a stratified 

 deposit, the joints diverging from the line of the dyke, enable us to decide that the mass is a part 

 of the Silurian system, though highly altered by the trap which traverses it. The principal joints 

 here range from north-west to south-east, are vertical, and completely distinct from any lines of 

 structure in the body of the trap rock. 



This dyke disappears to the north-north-east under hills of reddish Caradoc sand- 

 stone, the strata of which are much dislocated ; and to the south-south-east similar 

 effects are traceable in Powis Castle Park, at several parts near the Castle ; the highest 

 or calcareous beds of the Lower Silurian rocks being elevated into highly inclined 

 positions, throwing off the Upper Silurian or mudstone rocks. Strictly speaking, 

 the axis determined by the dyke of the Standard Quarries, whether measured on its 

 immediate flanks, or by reference to these lines of disturbance, is from N.N.E. to 

 S.S.W., but if viewed upon a larger scale, it will appear that the dislocation in the 

 higher ridge of the Upper Park changes its direction to E.N.E. and W.S.W., according 

 with that of the Breidden Hills, and it is therefore possible, that the dyke of Welch 

 Pool, and the lines of disturbance immediately proceeding from it, are only slight aber- 

 rations from a line of eruption of which the Breiddens was the chief focus : it is, however, 

 to be observed that the disturbed line of Welch Pool is parallel to the strike of the vol- 

 canic ridges of Corndon, whilst the Breidden Hills, next to be described, cut through 

 the stratified deposits in a direction which diverges 45° from those parallels. 



The Breidden Hills. 



These hills present two principal masses, the Breidden and the Moel-y-Golfa, which 

 extend from W.S.W. to E.N.E. in parallel ridges. Their summits consist exclusively 

 of trap, and they are separated by depressions in sandstone and shale. The Breidden, 

 which gives its name to the group, impends over the Severn in bluff faces, and its 

 rounded summit, 1199 feet above the sea, is surmounted by the pillar which comme- 

 morates the victories of Rodney, as expressed in the vignette at the head of this chapter. 

 The Moel-y-Golfa having a conical form, attains the height of 1 143 feet, and forms the 

 south-western end of the largest ridge, which extends four miles into Shropshire in the 

 hills of Middleton, Cefn-y-Castel, Builthey and Bauseley. The Criggan is a low central 

 elevation, which, when viewed from Welch Pool or the south-west, has the appearance 

 of a third parallel ridge, but it soon subsides. The Breidden is terminated on the north- 

 east by an expansion or contrefort called BrinfordWood. These picturesque hills present 

 themselves in very devious forms when viewed from different points of the surrounding 



