546 LOWER CAEBONIFEROrS OF XORTH-WESTERX EXGLAND. [DeC. I9 I 2. 



is characteristic of Z-C in the Bristol, Malahide, and Tournai 

 areas. The lowest layers, therefore, containing the Vaur/hania- 

 cleistoporoiLles Band must be provisionally correlated w^ith Z-C of 

 the South-'Western Province. 



The lowest fossiliferous horizon in the Xorth-AYestern Province, 

 found in Pinskey Gill (Eavenstonedale), contains a somewhat unique 

 fauna. The characteristic Spirifer appears to be unknown in the 

 Lower Carboniferous deposits of the Bristol District.^ The casts of 

 the little Camarotoechia-\\kQ brachiopod bear a distinct resemblance 

 to C. mitcheldeanensis, but are in too imperfect a state of preserva- 

 tion for exact determination. It will be best, therefore, for the 

 present to leave the correlation of these beds as an open question, 

 merely suggesting that they probably represent some portion of the 

 Zaphrentis Zone of the Bristol sequence, since they underlie the con- 

 glomerate which forms the base of the Z-C beds mentioned above. 



[Since this paper was read before the Society, I have had the 

 pleasure of going over a good deal of the ground in the Shap and 

 Ravenstonedale Districts with Dr. Vaughan, Mr. E. E. L. Dixon, 

 and Mr. E. G. Carruthers, when special attention was given to the 

 correlation of the beds with those of the South-Western Province, 

 At the conclusion of the visit, Dr. Vaughan expressed himself in 

 general agreement with the correlation set forth in the table on 

 p. 547. He would, however, not only include the Tliysanophyllum 

 Band in C.„ but w^ould extend that sub-zone downwards to the 

 top of the Algal Limestones. Although only a small thickness 

 of beds is involved, the change is important, as it throws the 

 Syringotliyris-cuspidata Beds into C.,, instead of C^, where the index- 

 fossil occurs typically in the Bristol District. 



Mr. Dixon, while recognizing that the fauna of the Solenopora 

 Sub-zone has affinities with that of C^, considers that the physical 

 evidence is in favour of his original view that submergence in the 

 northern area did not take place until deposits of C, age were 

 being laid down in the South-AVestern Province ; his view will be 

 found in the discussion published at the end of this paper (p. 585).] 



Correlation with Northumberland. 



The classification described in this paper can also be broadly 

 applied to the Lower Carboniferous successioii in Northumberland 

 and Xorth Cumberland, and by this means it is possible to esrablish 

 with some degree of certainty the equivalents, in Northumberland, 

 of the Bristol Zones. I have already given a general comparison 

 elsewhere.^ More recent work in Cumberland has shown that 

 several of the horizons established in Westmorland are also clearly 

 recognizable in the Xorth Cumberland and Border Districts ; but 

 the detailed investigation of the succession is not yet complete. 

 Mention may be especially made of the important development of 

 algal limestones in North Cumberland at an horizon equivalent to 

 that of the Solenopora Beds of Shap ; while other bands also present 

 in both districts are included in the accompanying table. 



1 ' Geology in the Field ' (Jubilee vol. Geol. Assoc.) pt. iv (1910) p. 683. 



