WALTER KEEPING ON THE 



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1 



(3) ffliyader to the Teifi Pools 

 (fig. 5). — In this section three 

 main folds are indicated, namely a 

 central anticlinal fold at Disgwylf a 

 in the Ehyader pale slates, with a 

 synclinal on its east and west. 

 The former is a comparatively 

 simple basin of pale slates beneath 

 the grits and conglomerates of 

 Cwm Elan and Gwastaden; the 

 latter, corresponding with the 

 Plynlimmon synclinal, is a much 

 more complicated structure, pro- 

 bably much affected by reversals. 



General Result of the East and 

 West Traverses (see fig. 6). — The 

 sections just indicated show that 

 the great area of Mid Wales is 

 made up of a thick series of im- 

 perfect slates, pale slates, shales 

 and grits, having a general re- 

 semblance and intimate connexion 

 throughout, as of one continuous 

 group, but divisible into the sub- 

 groups indicated in the beginning 

 of this paper. 



These rocks form one great pri- 

 mary synclinal extending from the 

 Aberystwyth axis to the east of 

 Ehyader, and from the west of 

 Llandeilo to Aberaeron. For in 

 the west of Cardiganshire we find 

 a great and continuous course of 

 easterly dips running inwards from 

 the coast ; and in the eastern half 

 of the area, in Eadnorshire and 

 Carmarthenshire, is a correspond- 

 ing grand set of westerly dips. 

 Subordinate but still very great 

 anticlinal folds along north and 

 south axes bring up on the east 

 the Metalliferous slates between 

 Plynlimmon and Ehyader, and on 

 the west the upper part of the 

 Aberystwyth grits, in the line of 

 Pont Erwyd and the Devil's 

 Bridge. Another, smaller fold 

 with the same result as the last, 

 runs from Ystrad Meurig north- 

 wards towards Machynlleth, thus 



