334 ME. T. E. SIELY ON THE CARBONIFEROUS [May I906, 



Atliyrls cf. planosidcata is not uncommon. Peticularia cf . reticu- 

 lata occurs rarely in the lowest part. 



Spirifer cf. bisulcatus occurs locally at some levels. Sp. cf . fur- 

 catus and Camaroplioria isorhgncha are locally abundant at the 

 base. 



OriJiotlietes aff. crenistria, mut. C, occurs not uncommonly through- 

 out, and is abundant at the top of the subzone. 



A well-marked, spinous mutation of Productus concinno- Martini 

 ( = Pr. cf. semireticidatus, mut. Sj) is abundant in the upper part of 

 the subzone. 



Productus aff. Cora, mut. C, occurs occasionally. Pr. 6 is abun- 

 dant at certain levels, and extremely prolific in the topmost beds. 

 Pr. aff. hemisphericus is not uncommon. Pr. punctatus has been 

 recorded l in this subzone. Specimens of a fimbriate Productus 

 occur not uncommonly. 



Ohonetes cf. papilionacea is prolific in the upper part, and is 

 associated, in the uppermost beds, with abundant specimens of 

 Cli. aff. comoides. 



Dielasma cf. Jiastata and Pugnacc cf. avgulatus occur very rarely 

 in this subzone. 



S 2 = Subzone of Productus all. Cora, mut. S 2 . {Coba- 

 subzone.) 



General lithological character. — Massive limestones, con- 

 sisting mainly of beds which are dark blue-grey or black in colour 

 and very compact in texture. 



The fauna of this subzone contrasts strongly with that of the 

 preceding subzone, for, although abundant in individuals, it is poor 

 in species. 



Coral-f a una : 



Lithostrotion Martini and variants. Very abundant throughout 



the greater part. 

 Syringopora ct'. distans. ~\ 



Syringojiora cf. geniculata. I q . ■. 



Carcinophyllitm aff. 0. ( 



Gyathophyllum Murchisoni (?) J 



Brachiopod-fauna : 



Seminnla ficoides and closely-allied forme. 1 Very abundant throughout 



Pi'oductus aff. Cora, mut. S 2 , and variants. J the greater part. 



Productus aff '. liemisphericus, increasing in numbers. 



Productus ' gigamteus^ abundant in the topmost beds. 



Chonetes cf. papilionacea, abundant at recurring levels. 



Clionetes aff. comoides. 



Orthothetes aff. crenistria, rare. 



Cyrtina aff. carbonaria occurs in the lower part. 



The subzone is especially characterized by Productus aff. Cora, 

 mut. S 2 , and by the maximum of Seminula. 



1 Productus punctatus is abundant at the base of S x in the Weston-super- 

 Mare district, but I have failed to record it at the same horizon in the Men dip 



