478 J. E. MAEE AJSD T. EOBEETS O^S THE 



are preserved in the Geological Survey lluseiiin from the limestone 

 of tMs region : — 



Triaueleus favus, Salt. 



Monticiilipora favulosa, Phill. 

 Beyrichia complicata, Sali. 

 Calymene cambrensis, Salt. 

 Asaphiis tyrannus, Murch. 



Leptsena sericea, Sow. 

 Orthis striatula, CoJir. 

 &c. &c. 



The limestone is also seen north of Stoneyford^ on the road 

 between IS'arherth and Clynderwen Station ; and similar limestone, 

 which has, however, not furnished us with any fossils, occurs at 

 Bullhook and Camrose, as marked on the Geological Survey map. 



4. Dicranograiotus Shales. — These beds immediately succeed the 

 Llandeilo limestone of Llandewi Yelfry, and are seen above the liine- 

 stone quarry at " P " in '■' Parsonage." They are black shales, with 

 some grit bands, and are usually crowded with graptolites, including 

 Dicranogrciptus ramosus, Olimacograj^tus hicornis, &c. We have 

 nowhere seen a section giving the complete series. At Llandewi 

 Velfry there is room for about 50 feet of shales betw.een the 

 Llandeilo limestone and the beds above the shales, but it is very 

 doubtful whether the whole of the shales are now represented here. 

 The uppermost beds of the series certainly occur at this locality. 

 They are well-defined, flaggy and sandy black shales, characterized 

 especially by the abundance of OrtJiis argentea, His., and may there- 

 fore be spoken of as the zone of OrtJiis argentea. 



Dr. Hicks (Q. J, G. S. vol. xxxi. p. 178) also places the Llandeilo 

 limestone between the Didymograptus- and Dicranogra]ptus-6h.^e^. 



Confirmatory sections. — The Dicranogra]jtus-s\iLdle^ are exposed to 

 a considerable extent to the north of the complex synclinal. 



On the west side of the Western Cleddau, they occur much folded 

 in the neighbourhood of Camrose, and at Camrose Mill the Dicrano- 

 gra^tus beds are again seen succeeding the Llandeilo limestone. At 

 Wolfsdale they have yielded Ogygia BucJiii. On the east side of 

 the Western Cleddau the beds set in at Kudbaxton, and we have 

 found graptolites at Green Plain, south of Trefgam Bridge. At 

 Clarbeston-Eoad Station also graptolites occur. The beds can then 

 be traced in several sections along the railway as at Pendwr, Long- 

 ridge Bridge, and Blaen Waen, between Clarbeston-Eoad and Clyn- 

 derwen Stations, and they appear to overlie the Llandeilo limestone 

 south of Bullhook, although the two are not in close proximity. 

 These beds are also brought up by folds to the south of this. ]S"orth 

 of Stoneyford they lie immediately over the Llandeilo limestone. The 

 Orthis-argentea zone is seen near Grondre, at Robeston Wathen, and 

 at Prendergast, but no Llandeilo limestone is exposed at these 

 places. 



We have then several independent sections showing the Dicrano- 

 ^r«29ius- shales immediately succeeding the Llandeilo limestone, and 

 the latter may, indeed, be looked upon as merely a calcareous 

 development of the black shales which occur below, within, and 

 above it. 



The fossils, other than graptolites, of the jDicranograptus-shales, 

 occur chiefly in the Orthis-argentea zone, with the exception of 



