Lm:-ZoyES IN THE BRITISH CARBONIFEROUS ROCKS. 



307 



There can Ijc no doubt that the Pendlesidc Series is well I'epresented in 

 North AVales, and includes the Teilia liniestoncis and the scries of Lady 

 McLaren's Quarry, and the black .shales and limestones known aa 

 the Holywell Shales. Possibly the latter arc somewhat higher in the 

 series than the Teilia beds. The fauna of the Holywell Shales is fairly 

 rich and contains : — 



Posulonoiiiya Bcoberi. 



,, membianacea. 



I'terinopeclen papyiaceus. 



„ carbonaiius. 



AcLiuoplcria persulcata. 

 T-eiopturia, cf. longirostrit^. 

 rosidonoiiiya minor. 



,, laevis. 



Orllioccras .^p. 

 Ulypliioceias rcticulatiim. 



,, I'billipsii 



„ diadema. 



I'roductus coia (late luutatiou) 

 Ijingula iintiloidcs. 

 Kecd-like plant remains. 



Tlicse beds are well exposed in the quarry E. of Holywell, above 

 the workhouse, and there is a good section in the dingle between Holy- 

 well and the Bagillt Ixoad, and also in that road. 



Tliese black shales, which form the upper part of the Pendlesidc 

 Series of North Wales, are known as the Holywell Shales. They were 

 unfortunately mapped and correlated with the Lower Coal Measures of 

 Lancashire ; a mistake indicated at once by a study of the fauna and the 

 absolutely different lithological characters of both series and the negative 

 evidence afforded by the absence of the characteristic Coal Measure 

 fauna. 



Succeeding the Holywell Shales are a thick series of sandy shales and 

 the (iwespyr Sandstone, Avhich we estimate to hn about 300 feet thick. 



This series we provisionally con-elated with the Millstone Crit Series 

 on account of its position. The sandstone is fine-grained and contains 

 mimerous fragments of plant remains. It also contains a good deal of 

 felspar. 



We therefore classify the Carboniferous succession of North Wales as 

 follows : — 



Coal Measures , 

 Millstone Grit 

 I'endleside Series 

 Oyathaxonia beds 

 Upper Dibunopliyllnm beds 

 Lower Dibunophyllum beds 

 Scminula beds, a few feet . 

 Basement beds 



C.M. 

 M.G. 

 T. 



1>, 

 i\. 



Is., 

 J - 



ExcellcJit work has been done by Mr. T. F. Sibly on the Carboniferous 

 limestone of Weston-super-Mare and the Mendij) area. His papers 

 have both been published in tlic ' Quar. Jour. Ceol. Soc' He has found 

 it po.s.siblc to carry on the subdivisions proposed l)y J )r. A. Vaughan for 

 the Bristol area and to demonstrate the occurrence of each zone and 

 sub-zone in the districts he describes. Naturally in examining new areas 

 some fresh details have come to light, but the extension of Dr. Vaughan's 

 lines is veiy important. 



J-)r. Vaughan himself has demonstrated that his zones can be traced 

 throughout South Wales ; consequently we may now consider that the 

 south-west Carboniferous province has been accurately zoned. In con- 

 junction with Dr. Matley he has shown that the Carboniferous succession 

 at Rush contains the whole of the zones which range from the Upper 



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