170 Hind: Carboniferous Geology. 



sphoericum and Posidonomya becheyi.* I have seen the following 

 species from Doddiscombleigh : — 



Glyphioceras reticulatum. \ Seminula ambigiia. 



Stroboceras sulcatum. \ A Rhynchonellid. 



Posidonomya becheri. 



Mr. Ussher states | : — ' As regards the relative position of 

 the Codden Hill beds and Posidonomya Limestones and Shales, 

 ' wherever these two types are recognisable on the North or 

 South Crop, the Limestone Series is invariably the uppermost.' 

 Glyphioceras spirale is a common fossil in the upper beds of the 

 Lower Culm {Posidonomya beds) at Bampton, Waddon-Barton 

 and elsewhere, both in the Northern and Southern crops. 



SOUTH WALES. 

 At Bishopton in the Gower peninsula is a most typical 

 sequence — the Dihunophyllum beds of the phases D2 and D3, 

 the latter being represented by the dark limestones and shales 

 of Oystermouth Castle. On these rest the Bir.hopton beds, con- 

 sisting of a Series of cherty beds passing up into Black Shales 

 with Posidoniella laevis and Glyphioceras bilingue. I think it 

 probable that the cherts may represent in part the Codden Hill 

 beds, but there seems to be a gap of the higher Series from the 

 zones Posidonomya becheri to the incoming^of the Glyphioceras 

 bilingue beds, probably not any very great thickness of beds, 

 but the zones here afford evidence of a local unconformity. Mr. 

 L Rogers has discovered Glyphioceras reticulatum in the Culm, 

 near Barnstaple, so that the following life zones all occur in 

 the Culm of Devonshire : — 



Gastrioceras listeri. 

 Glyphioceras reticulatum. 

 Glyphioceras spirale. 

 Posidonomya cecheri. 

 Prolecanites compressus. 



And there can be httle doubt that the Culm of the South-west, 

 and the Pendleside Series of Co. Clare and the Midlands are 

 homotaxial equivalents. This view is amply borne out on 

 examining the Carboniferous succession in Belgium and Ger- 

 many, where the Namurien and Culm are characterised by a 

 fauna and flora identical with that of the Pendleside Series. 



* Mem. Geo]. Sur. England and Wales ; ' The Geology of Country 

 round Exeter,' p. 9. 



t The Geology of the Quantock Hills, and of Taunton and Bridge- 

 water, p. o:^, 



{To be continued). 



Naturalist 



1 



