xvi 



CONTENTS. 



CHAPTER XXIII. 



THE BREIDDEN HILLS AND ADJACENT TRAP AND ALTERED ROCKS. 



Page 



Line of Dislocation produced by the eruption of the Breidden Hills, extends from Montgomeryshire 



through Shropshire into Staffordshire. (PL 32. figs. 5 — 8.) 287 



CHAPTER XXIV. 



SILURIAN ROCKS OF MONTGOMERYSHIRE. 



Range and Distribution of the Silurian Rocks in Montgomeryshire and the adjacent Districts of Shrop- 

 shire and Denbighshire. — Their passage into Cambrian Rocks. (PI. 32. figs. 1, 2 and 9. PI. 33. f. 1.) 300 



CHAPTER XXV. 



SILURIAN, CAMBRIAN, AND TRAP ROCKS IN RADNORSHIRE. 



Upper and Lower Silurian Rocks of Presteign, the Vale of Radnor, Radnor Forest, &c. — Cambrian Rocks 



in "West Radnor. — Volcanic Group and Altered Rocks of Old Radnor. (PL 33. figs. 1—4.) 311 



CHAPTER XXVI. 



TRAP AND ALTERED ROCKS OF RADNORSHIRE {continued). 



Group of Llandegley, Llandrindod, and Carneddau near Builth. Mineral Waters of these Tracts. — 

 (PL 33. figs. 3 — 7. See also Map and opposite sketch of the southern end of Carneddau, near 

 Builth) 324 



CHAPTER XXVII. 



SILURIAN, UPPER CAMBRIAN, AND TRAP ROCKS OF BRECKNOCKSHIRE. 



Silurian Rocks in Brecknockshire, including the anticlinal Ridge of Brecon. — Trap, altered Rocks, and 



Mineral Waters of Llanwrtyd. (PL 31. figs. 1, 6 — 9.) 336 



CHAPTER XXVIII. 



SILURIAN, UPPER CAMBRIAN, AND TRAP ROCKS OF CAERMARTHENSHIRE. 



Course of Upper and Lower Silurian Rocks maintained by superposition and organic remains. — Great 

 changes in lithological structure. — Lower Silurian where best developed — in parts affected by slaty 

 cleavage. — Fine exhibition of Llandeilo flags, their passage into Cambrian System. — Change of strike 

 as the strata pass into Pembrokeshire. — Cambrian Rocks. — Trap and Altered Rocks. — Mines, &c. 

 (PL 34. figs. 1—11.) 347 



