1 54 CARBONIFEROUS. 



In South Brecknockshire they appear to be but thinly repre- 

 sented, and also in North Wales at Moel Hiraddug, on the borders 

 of Flintshire and Denbighshire. 



The beds may be well studied in East and West Angle Bays, and 

 east of Stackpole Quay in Pembrokeshire.^ They were termed the 

 Caldy Series by John Phillips. Some of the shales here are cleaved 

 and become like the Carboniferous Slate of Ireland. 



Amongst the fossils are Rhynchotiella plairodon, Athyris Royssii, 

 Orthis resupinata, Spirifera diipUcostata, S. striata, Discina iiitida, 

 Chonetcs perlata, Carnarophoria globidina, Comilaria qiiadn'sulcata, 

 Sanguinolites cofiiplatiatiis, Modiola jSIacadami \ Poteriocrinites, Platy- 

 crimis, and other Crinoidal remains, as well as Trilobites of the 

 genus Phillipsia} Many remains of Fishes also occur, and some 

 Plant-remains {Sphmopteris ?) have been noticed in North Wales. 



At or near the base of the Lower Limestone Shales of Clifton 

 near Bristol and the Mendip Hills, is found the fish-bed or palate- 

 bed, a dark red conglomeratic bone-bed, four to six inches thick, 

 so named on account of the number of coprolites, palatal teeth and 

 spines of Fishes met with in it. The Fish-remains are those of 

 Psanunodus, Cladodus, Ctenacanthus, Cochliodus, etc. Brachiopoda 

 also occur, as well as the Polyzoa Fenestdla and Ceriopora. 



Trilobites are met with near the junction with the Old Red 

 Sandstone at Burrington, on the Mendip Hills, and near the top of 

 the Shales at Clifton near Bristol. Many fossils have been obtained 

 by Mr. E. Wethered at Drybrook, in the Forest of Dean.^ (See 

 also p. 143.) 



The lower part of the Culm-measures of North Devon, as well 

 as the Pilton, Baggy, and Marwood Beds, are probably of Lower 

 Carboniferous age. (See p. 122.) 



In the South-west of England and in South Wales, the Lower 

 Limestone Shales form a band of generally depressed land sur- 

 rounding the Old Red Sandstone, bounded again by an escarpment 

 of the Carboniferous Limestone. Swallow-holes frequently mark 

 their junction with the newer rock. 



From their appearance, on the Mendip Hills, they have some- 

 times led to fruitless searches for coal. Such soft black shales 

 often contain a good deal of carbonaceous matter, but they also 

 contain (as colouring matter) sulphide of iron. 



CARBONIFEROUS LIMESTONE. 



The Carboniferous Limestone, so named by Conybeare in 1822, 

 is generally a tough bluish-grey crystalline limestone, which emits 

 a fetid odour when fractured. This odour is probably due to 

 sulphuretted hydrogen. The rock occurs in beds of variable 



1 Murchison, Silurian System, p. 383. See also J. W. Salter, Q. J. xix. 477. 



2 For a detailed account of the fossils see W. W. Stoddart, Proc. Bristol Nat. 

 Soc. ser. 2, vol. i. p. 318. 



^ Q. J. xxxix. 211. 



