324 ME. T. E. SIBLY ON THE CAEBONIFEEOTJS [May T906, 



14. On the Caebonifeeotjs Limestone (Avonian) of the Mendip 



Aeea (Soheeset), with especial reference to the Paljeontological 



Sequence. By Thomas Feanklin Sibly, B.Sc, F.G.S. (Read 



February 7th, 1906.) 



[Plates XXXI-XXXV] 



Contents. 



Page 



I. Introduction 324 



II. The Faunal Sequence in the Mendip Area 326 



III. General Stratigraphy of the Carboniferous Limestone in the 



Mendip Area 336 



IV. Description of Exposures in the Mendip Area 338 



V. Correlation of the Mendip and Bristol Areas 353 



Note on the Separation of the Syringothyris-Zone and the 



Seminula-Zoue in the Mendip Area 358 



Note on the Distinctness of the Clevedonian and Kidwellian 



Faunas in the Mendip Sequence 359 



VI. Summary 360 



VII. Notes on the Geology of the Ebbor-Kocks District, near Wells 361 



VIII. Notes on certain Corals and Brachiopods included in the Faunal 



Lists 366 



I. Introduction. 



This paper contains the results of a detailed examination of the 

 Carboniferous Limestone in the Mendip area. 



The object of my work has been the complete investigation of the 

 faunal sequence in the Carboniferous-Limestone Series, following 

 on the lines laid down by Dr. Arthur Vaughan, in his great paper l 

 on ' The Palseontological Sequence in the Carboniferous Limestone 

 of the Bristol Area.' Detailed work in the Mendips has shown 

 that the system of zones and subzones, established by Dr. Vaughan 

 in the Bristol sequence, requires only very slight modification to 

 co-ordinate accurately the faunal sequence in the Mendip area. 

 The correlation of the Mendip and Bristol areas is treated fully in 

 the present paper, my comparison being based on Dr. Vaughan's 

 paper, to which I make frequent reference. 



I am indebted to Mr. H. B. Woodward's Geological Survey- 

 memoir on i The Geology of East Somerset & the Bristol Coalfields/ 

 published in 1876, and to a paper by Prof. C. Lloyd Morgan, entitled 

 4 Mendip Notes,' published in the Proceedings of the Bristol 

 Naturalists' Society, 2 for much valuable information and guidance. 

 To my recent paper 3 on ' The Carboniferous Limestone of Burrington 

 Combe/ which deals fully with the Burrington section, I refer 

 frequently. 



The Carboniferous Limestone presents more or less complex 

 structural features in several parts of the Mendip area, and it is to 

 be hoped that the application of palseontological study to these 

 problems will furnish correct solutions. The time at my disposal has 



1 Quart. Journ. Geol. Soc. vol. Ixi (1905) pp. 181-305. 



2 N. s. vol. Yi (1890-91) pp. 169-82. 



3 Proc. Bristol Nat. Soc. ser. 4, vol. i, pt. 1, 1905 (issued for 1904) pp. 14-41. 



