﻿Yol. 6 I.] SEQUENCE IN IHE BEISTOL AKEA. 221 



Syrinyothyris-Zone (C). 



Sequence in ascending order : — 



(1) Thick encrinital, dolomitic limestones, comparatively 



unfossiliferous. 



(2) A very fossiliferous encrinital band (the ' sub-Oolite '). 



This band is non- oolitic in the lower portion, but oolitic 



in the upper. 

 (H) A band of pure oolite (the ' Caninia-Qolite '). 

 (4) Thick dolomites, with subsidiary shales ; unfossiliferous. 



Exposures : — 



(1) is well exposed on each side of the cutting. 



(2) can be excellently worked in the lower portion of the 



oolite-quarry, west of the tunnel. 



(3) forms the upper part of this quarry, and also extends on 



each side of the cutting as far as the western mouth of 

 the tunnel. 



(4) forms the sides and roof of the tunnel, and extends from 



the eastern mouth of the tunnel to near the end of the 

 cutting. 



Fauna: — 

 Corals : 



Zapfirentis afF. Phillipsi occurs sparingly in (1) and in the 

 lower part of (2) ; a single specimen has been found in 

 the upper part of (2). 

 Caninia: one specimen only was found, namely, in the 

 lower part of (2). 



Brachiopods : 



Chonetes cf. hardrensis is extremely abundant in the lower 

 part of (2), and is also met with in (1). This species is, 

 as we ascend, gradually replaced by Chonetes aff. papi- 

 lionacea, which teems in the upper part of (2). 



Spirifer an , clathratus and ffliipidomella aff. Michelini are 

 found infrequently in the lower part of (2). 



Orihotetes crenistria (cf. var. Kellii) occurs abundantly in the 

 upper part of (2), in association with Clionetes aff. papilio- 

 nacea and an occasional specimen of Syringothyris aff. 

 laminosa. It extends on into (3). 



Productus aff. semireticulalus occurs rarely in the upper part 

 of (2). 



Euomphcdus occurs in considerable numbers in the upper 

 part of (2) and in (3). 



