process-blocks and other illustrative figures. xv 



Fig. Page 



7. Map showing the lines of flexure in S.E. England 454 



8. Model illustrating the physiography of the Seaford district ... 436 



1. Section showing the general relations of the members of the 



Plynlimon Stage near Nant-y-M6ch 470 



2. Section from Drum Peithnant to Craig Yspio 474 



•3. Section showing the Pont Erwyd Stage and its relations to the 



Plynlimon Stage near Eistedclfa Gurig 476 



4. Section from Craig Yspio to Cwm Ergyr 476 



5. Plan of the Fuches-gau locality 480 



•6. Section from the Afon Castell over Banc Bryn-chwith . 483 



.7. Vertical section through a part of the eyphus zone 486 



8. Vertical section through the eyphus zone, Rheidol Gorge 487 



9. Plan of section along Nant Fuehes-wen 494 



10. Plan showing the distribution of the Rheidol & Castell Groups 



near Dyffryn Castell 498 



11. Vertical section of the Pont Erwyd Stage 504 



12. Section from N. of Yspytty Cynfyn to Llyn Rhuddnant 508 



13. Vertical section of the Ystwyth Stage 517 



14. Plan of folding, about half a mile N. of Pont Erwyd 523 



15. Section along the line A-B in fig. 14 523 



.16. Section illustrating the outline of the ground produced by 



pitching folds 524 



47. Diagram illustrating the effect of pitch on the apparent dip of 



rock-outcrops 526 



18. Monograptus atavus, sp. nov 532 



19. Monograptus rheidolensis, sp. nov 534 



1 . Barren surface of limestone, with ' grikes,' Bally vaghan 540 



2. Results of pluvial & marine action on the limestone, Black 



• Head 540 



3. Map showing the outcrop of the Carboniferous Limestone in 



County Clare 543 



4. Terrace in the limestone escarpment, Burren 544 



■5. Foot of the main escarpment, showing scree-formation, Burren. 545 



-6. Natural limestone amphitheatre of Ballyvaghan 546 



7. Eastern edge of the Burren plateau, Glencolumbkille 546 



