Summit of the Breidden, from a drawing by Mr. T. Webster, F. G.S. 



CHAPTER XXIII. 



The Breidden Hills, with other Trap and altered Rocks in Montgomeryshire. 



Line of Dislocation produced by the Eruption of the Breidden Hills shoivn to extend 

 through Shropshire into Staffordshire. (PI. 32. figs. 5, 6, 7 & 8.) 



The chief phenomena explained in this chapter are connected with the Breidden 

 Hills, so justly admired for their picturesque forms when viewed from the surrounding 

 region. As, however, the exposition of their relations will naturally lead to some im- 

 portant inferences with which this chapter must terminate, I first describe certain 

 minor detached trap rocks of the same neighbourhood. 



In the Vale of Montgomery, about two miles west of Chirbury and three miles from the western 

 nank of the Corndon Hills, described in the last chapter, trap rocks again rise up in three places, 

 on a line running from north-north- east to south-south- west. The most northern, called Nant- 

 Cribba, is a small boss, situated a little to the south of the point where the road from Bishop's 

 Castle and Chirbury unites with that from Montgomery to Welch Pool. Having been long used 

 for the roads, excavations have been formed in the rock about one hundred yards in breadth, and 



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