﻿Vol. 6 1.] LIMESTONE OF WESTON -SUPER-MARE DISTRICT. 559 



Brachiopod-fauna : — 



Cliothyris glabristria. Orthoietes aff. crenistria. 



Spirifer ef. ductus. Rhipidomella aff. Michelini. 



Spirifer aff. clathratus, and Schizophoria resupinata. 



var. Chonetes cf. hardrensis. 



Reticularia aff. lineata. Chonetes papilionacea. 



Syringothyris cuspidata. Product us pustulosis. 



Syringothyris aff. laminosa. Productus aff. semireticulatus. 

 Leptcena analoga. 



In the upper part of Z , the abundance of Zaphrentis aff. cornu- 

 copia and Syringopora 6 is very characteristic. Amplexus and 

 Michelinia are very common. 



Horizon y is clearly defined by the extreme abundance of Caninia 

 cylindrica in association with Zaphrentis spp. 



Syringothyris-Zone (Zammosa-subzone). 

 Brachiopod-fauna : — 



Syringothyris cuspidata. 

 Syringothyris aff. laminosa. 

 Orthoietes aff. crenistria. 



Chonetes cf. comoides. 

 Chonetes pmpilionacea. 



The basal beds of the ' Camma-Oolite ' contain abundantly 

 Chonetes and OrtJiotetes. 



IV. Comparison with Neighbouring Areas. 



(1) The Weston-Worle Ridge. 



Some interesting conclusions are arrived at, by comparing the 

 development of the Syringothyris-Zone in this area with the 

 equivalent part of the sequence in (1) The Clevedon district 1 ; and 

 (2) the Burrington section. 2 Clevedon lies at the western end of the 

 Clifton-to-Clevedon ridge, about 8 miles north-east, slightly north, 

 of "Weston-super-Mare, and its immediate neighbourhood is the 

 nearest part of the Bristol area of which we have a complete 

 knowledge. Burrington Combe lies about 9| miles east 10° south 

 of Weston, and the development here may be regarded as typical of 

 the Western Men dips. 



The occurrence of representatives of the * laminosa-dolomites ' 

 and ' Caninia-Oolite' in C t in the Weston area constitutes a dis- 

 tinct link with the Clevedon district and, at the same time, a 

 variation from the Burrington type. In the upper part of the zone, 

 however, the thick series of oolitic limestones, containing a typical 

 Syringothyris-f&\m&, indicates the predominance of a Mendip 

 facies ; for this development is exactly paralleled in the Burrington 

 section by Horizon 2 and the greater part of the main Syri)iyothyris- 

 Zone, while differing considerably from the equivalent part of the 

 Clevedon sequence. 



1 For an account of the Carboniferous Limestone of the Clevedon district, 

 see A. Vaughan, Quart. Journ. Geol. Soc. vol. lxi (1905) pp. 225-28. 



3 For an account of the Burrington section, see T. F. Sibly, ' The Car- 

 boniferous Limestone of Burrington Combe ' Proc. Bristol Nat. Soc. ser. 4, 

 vol. i, pt. i, 1905 (issued for 1904) pp. 14-41. 



