Yol. 62. ] CARBONIFEROUS LIMESTONE OF THE MENDIP AREA. 379 



marine conditions which existed during the deposition of the 

 Devonian rocks of Devon. 



In conclusion, the speaker enquired as to which of the volcanic 

 horizons proved at Weston-super-Mare corresponded to the igneous 

 rock at Uphill. 



The Bev. H. H. Win wood said that he hoped that the zonal wave 

 would continue to roll on, and that the admirable work done by 

 Dr. Yaughan, and his able pupil the Author, amid the Carboniferous 

 rocks of the West would be taken up by geologists in the North. 

 He asked the Author whether there was any evidence of faulting 

 in the limestone-rocks of the Ebbor Gorge besides the fact, as 

 stated, of the break in the usual zonal succession. The absence or 

 extreme paucity of the ' Modiola '-phase in the Mendips was an 

 argument for the use of the more general term Cleistopora. He 

 noted some new terms again introduced — ' Clevedonian,' ' Kid- 

 wellian,' and ' Avonian ' — somewhat puzzling to older geologists. 

 Would the two former stand the test of criticism? The last- 

 mentioned designation, ' Avonian,' as representing the typical 

 Western section, might perhaps be useful. 



Mr. C, B. Wedd stated that, in Eastern Derbyshire, the coral- and 

 brachiopod-faunas of the upper part of the Carboniferous Limestone 

 agreed closely with the DibunopTiyttum-Zone of Dr. Yaughan's 

 classification. A better acquaintance with the latter and with the 

 fauna of Eastern Derbyshire showed that this agreement was closer 

 than he had supposed, and that all the Upper Limestone, at least 

 down to the second bed of toadstone, could be assigned with con- 

 fidence to the Upper Dibunophyllum-Zone (D ). This included 

 nearly the whole of the limestone exposed in the neighbourhood of 

 Wirksworth, Cromford, Bonsall, Matlock, and Derby, and all the 

 strata seen in the inliers of Crick and Ashover. 



Sir Archibald Geikie expressed the pleasure which geologists in 

 this country could not but feel that the reproach was now being 

 removed that they had left the great Carboniferous Limestone of 

 the British Islands without any attempt to subdivide it into 

 palaeontological zones. He hoped that, in introducing new strati- 

 graphical terms, regard would be had to the detailed work of 

 the Continental geologists, particularly those of Belgium, in the 

 Carboniferous Limestone. 



The Author thanked the Fellows for their kind reception of his 

 paper. In answer to Mr. Dixon, he stated that the igneous rock 

 at Uphill was associated with Upper Zaphrentis-Be&s, and therefore 

 occurred at the lower of the two volcanic horizons. Replying to 

 the Bev. H. H. Winwood, he explained that, although the 

 exposures north-east of the Ebbor Yalley did not furnish any 

 direct proof of the existence of a fault between the Upper 

 Dibunophyllnm-'Beds and the Lower Seminula-Beds, such evidence as 

 there was undoubtedly favoured that view. The terms Clevedonian 

 and Kidwellian had been suggested by Dr. Yaughan for the lower 

 and upper stages, respectively, of the Avonian, because it was not 



