Vol. 62.] ROCKS OF WESTERN CAERMARTHES SHIRE. 641 



less irregular curve along the eastern brow of ' Pale Mountain/" 

 between Greystones and Dol-dderwydd, where the beds are cut off 

 by a fault. 



Members of the series are seen near Forest Tunnel and in the 

 wooded ground north of Great Pale. A thin band of mudstones 

 cropping out in the wood has yielded some fragments of fossils 

 including Ortliis, Airy-pa (?), and trilobites (Acidaspis Brightii ? and 

 Trinucleus ?). 



The grits have been quarried in Pale Wood and at Penygraig. 

 West of the latter place they are either faulted out, or overlapped 

 by the Old Red Sandstone ; but they are well exposed again in 

 Middleway Dingle and in Penyback Quarries, south of Whitland. 

 In the quarries the beds are vertical, and exhibit beautiful samples 

 of ripple-marks, which give a clue as to the conditions under which 

 they were laid down. Fossils are extremely rare in these beds — 

 so much so, that with the exception of the specimens found in 

 Pale "Wood, only one or two poor unidentifiable fragments have 

 been discovered. 



Whether these beds are of true Lower Llandovery age has not 

 been definitely settled ; but it is quite clear that they are younger 

 than the Bala rocks of this region, and older than the Old Red 

 Sandstone, under which they are seen to pass at several points. 



IV. Concluding Remarks. 



It is deemed unnecessary to take up any space for correlation, 

 for most of the beds agree closely with the beds of other Welsh 

 areas, which have been carefully and fully worked out by various 

 authors. 



The Tetrag^rtus-'Beds are, in most respects, in complete 

 agreement with those beds at St. David's, the fauna at Blaencediw 

 being identical with that found at Whitesand Bay (Miss Elles). 



The Vidymograptus-bifidus and D.-Murchisoni Beds of this region 

 are, lithologically, very similar to those beds as exposed at Llanvirn 

 and Abereiddy, and the two faunas are practically identical. 



The Asaphus-tyr annus Beds, although varying much in lithological 

 character, agree palaeontologically with beds of that age in the 

 typical areas of Llandeilo and Pembrokeshire. 



The Dicranograjrtus-Beds are like those of Pembrokeshire in 

 some respects, but there is one feature that calls for special 

 remark. Miss Elles says that Lep>togra2)tus-Beds were not known to 

 occur in South Wales till they were discovered at Mydrim. These 

 beds, she says, are on the same horizon as the Rorrington Flags of 

 Shropshire. 



The three lower members of the Bala-Caradoc Series of this area 

 are so like the Robeston-Wathen, the Sholeshook Limestones, and 

 the Redhill Beds of Messrs. Marr & Roberts, that they could 

 hardly be mistaken by anyone that had seen those beds in 

 Pembrokeshire. There is, however, a slight lithological difference 

 between the fourth member (£) and the Slade Beds of Haver- 



