﻿240 DR. A. VAUGHAN ON THE PALJEONTOLOGICAL [May 1905, 



In the lower beds Zaphrentis aff. cornucopia is abundant, and fine speci- 

 mens can be obtained. The uppermost beds show an unequalled 

 development of the ' laminosar AolomiteB.' Chonetes aff. papilionacea 

 and Orthotetes crenistria mut. C occur in profusion. 



(b) A limestone-quarry. — This quarry lies a short distance 

 south-west of the last. It is mainly composed of an unfossili- 

 ferous limestone, which is perfectly white (the ' Caninia -Oolite '). 

 At the base are the uppermost beds of the ' Z«min os«-dolomite,' 

 teeming with Chonetes aff. papilionacea and Orthotetes crenistria. 



(c) ' Near' Cromhall. — In Mr. Champions Collection there 

 are specimens of Lithostrotion Martini, which certainly indicate 

 the Seminula-Zone. 



I have no doubt that a very complete section could be con- 

 structed, from all the exposures between Cromhall and Charfield ; 

 the exact resemblance of those exposures which I have examined, 

 to those already described in other parts of the Bristol area, 

 suggests, however, that the results would present no special 

 interest. 



(E) The Backwell-Wrmgtoii Mass. 



This triangular mass of Carboniferous Limestone, which mea- 

 sures 51 miles from west to east and 3| miles from north to south, 

 lies south-west of Bristol and due west of Dun dry Hill. 



The general structure of the mass is an anticline, the crest of 

 which runs west-and-east, a little south of Broadfield Farm, thus 

 dividing the mass into two very unequal parts, namely, a broad 

 northern part and a much narrower southern part. The crest of 

 the anticline had been eroded in post-Carboniferous times and is 

 now partly concealed, immediately south of Broadfield Farm, beneath 

 lihastic and Liassic deposits. 



Detailed Account. 

 Upper Tournaisian. 



Resupinata-suhzone (including Horizon y). 



Exposures. — Along the crest of the anticline and, under- 

 lying the lavas of Goblin Combe, on both sides of the anticline. 1 

 Fauna: — 



Zaphrentis aff. Pkillipsi. 

 Zaphrentis aff. cormccopi(g. 

 Caninia cylindrica. 

 Amplexus cf. coralloides. 



Spirifer aff. clathratus. 

 Syringothyris aff. laminosa. 

 Cliothyris sp. 



The only point that is worth emphasizing is the strong definition of 

 Horizon y, a fact which indicates our approach towards the Menclip area, 

 where Caninia and Amplexus occur abundantly. 



1 C. Lloyd Morgan & S. H. Reynolds, Quart. Journ. Geol. Soc. vol. lx (1904) 

 137. 



