﻿Vol. 64.] BALA AND LLANDOTERY EOCKS OF GLYN CEIEIOG. 



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of fine and coarse beds, and the occasional inclusion of thin seams 

 of interbedded slate, make it certain that the band as a whole is 

 contemporaneous with the beds among which it lies. We have 

 found no trace of the intense metamorphism of the overlying and 

 underlying beds to which Messrs. Cope & Lomas refer. 



(2) Teirw Beds. — The beds between the Cwm-Clwyd Ash and 

 the Craig-y-Pandj Ash may be divided roughly into (i) a lower 

 division, consisting chiefly of sandstones and grits with subordinate 

 slates ; and (ii) an upper division, consisting chiefly of slates with 

 subordinate sandstone-bands. 



The lower division is well exposed in the valley of the Teirw, 

 especially upon the southern bank of the stream ; in Teirw-Hill 



Fig. 3. — Slate-fragments in the grits of the Teirw Beds, at the 

 quarries on the right hank of the Ceiriog at Pandy. 



6 vnches 



v'-^/:r,ry\'v.(:-^-:^(-^-. 



[The oblique lines show the direction of the bedding.] 



Quarry ; and in the new quarries opened on the right bank of the 

 Ceiriog near Pandy. At Cwm Clwyd the sandstones do not lie 

 directly on the ash, but are separated by some 50 or 60 feet of 

 slate. Many of the beds are very coarse and contain volcanic 

 fragments, while others are fine and compact. False bedding is 

 occasionally well shown. The coarser beds are remarkable for 

 the number of flattened fragments of slate that they contain 

 (see fig. 3). Some of these are rounded or disc-like in shape, while 



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