CARBONIFEROUS LIMESTONE. 



157 



Stephen and Egremont. It may be seen near Ulverston, Cartmel, 

 Kendal, Kirkby Lonsdale, Sedbergh, Orton, Lowther, Caldbeck, 

 Cleator, etc. Everywhere it forms bold hills ; often presenting 

 rough precipices toward the Lake Mountains, which are known by 

 the name of " Scars."' Its rests unconformably on the older rocks. 



The Limestone is much quarried in the neighbourhood of Hesket 

 Newmarket. 



In the Isle of Man the Carboniferous Limestone series consists 

 of the Poolvash black marble and limestone group, overlaid by the 

 ^ Posidonia schists,' with Posidonomya Bechcri, and underlaid by the 

 (lower) Castletown limestone, and the Old Red Conglomerate.^ 

 (See p. 144.) 



In the Isle of Anglesey the Carboniferous Limestone is repre- 

 sented by the grey and black Pentraeth Limestone, with occasional 

 beds of sandstone. The thickness of the limestone series here is 

 estimated at from 200 to 500 feet. The beds are exposed on the 

 shore of Lligwy Bay, and the passage from the Old Red Sandstone 

 and conglomerate, through yellow sandstone, thin shales, and 

 limestone with quartz pebbles, is on the whole gradual.^ The 

 Limestone is also exposed on the Caernarvonshire side of the 

 Menai Straits. 



In Denbighshire and Flintshire the Carboniferous Limestone 

 has been divided as follows by Mr. G. H. Morton :* — 



No7-th Flintshire. 

 Upper Black 



Limestone 

 Upper Grey ) 



Limestone . \ 

 Middle White 



Limestone . 

 Lower Brown 



Limestone . 



150 



600 



South Flintshire. 

 Arenaceous 



Limestone . 

 Upper Grey 



Limestone . 

 Middle White 



Limestone . 

 Lower Brown 



Limestone . 



400 



200 



600 



100 



Llangollen. 

 Upper Grey ) 



Limestone. \ 

 Upper White 



Limestone . 

 Lower White 



Limestone . 

 Lower Brown 



Limestone . 



300 

 300 



480 



1 150 feet. 



1300 feet. 



1200 feet. 



In North Flintshire the Black Limestone (known as the Aberdo 

 Limestone) is quarried at Afon Goch, and near Holywell. Here 

 the beds yield Posidonomya Bccheri, Aviailopeclefi papyraceiis, Gonia- 

 tites bilinguis, etc.® South of Halkin Mountain, the upper part of 

 the Carboniferous Limestone contains alternations of sandstone 

 and limestone, and this feature continues to Llandegla, in the 

 neighbourhood of Mold. 



^ Article by J. Phillips, in Black's Guide to the Lake District, p. 253. 



2 Rev. J. G. Gumming, Isle of Man, 1848; Q. J. ii. 317. See also G. H. 

 Morton, G. Mag. 1879, p. 212. 



^ A. C. Ramsay, Geol. North Wales (Geol. Survey), edit. 2, p. 256. 



* Proc. Liverpool Geol. Soc. iii. 166, iv. 390. See also the Carboniferous 

 Limestone and Cefn-y-Fedw Sandstone, etc., by G. H. Morton, 1879 (reprint 

 of former paper). 



® A. Strahan, Geology of Rhyl, etc. (Geol. Survey), p. 8. 



