﻿196 DE. A. VATTGHAN ON THE PAL^EONTOLOGICAL [May I905, 



Former designation. — The whole of the Middle Limestones, 

 with the exception of the very topmost beds (which form the 

 lower part of Zone D) and of the lowest beds (already described 

 under subzone S x ). 



Where exposed in the Avon section : — 

 Clifton side : 



(1) The upper two-thirds of the Great Quarry, and the rocks at 



the side of the line up to the bottom of the new Zigzag 

 Path. 

 Note. — All the beds above the base of the oolite (which occurs about the 

 middle of the Great Quarry) are repeated by the Great Fault in 

 St. Vincent's Bock. 



(2) In this repetition the higher portions of the Seminula-Zone 



are exposed, from the Great Fault (near the bottom of Bridge- 

 Valley Road) almost up to the wall at the bottom of the 

 old Zigzag Path. 



Leigh Woods side : 



(1) Quarry 4, except the lowest beds ; along the side of the line ; 



Quarry 5 and the lower part of the series through which 

 the tunnel is bored. 



(2) (Owing to the repetition by the Great Fault). Along the 



side of the river-path, from Nightingale Valley to the end of 

 the riverside exposure. 



(3) Also in the disused quarry to the right of the road, immedi- 



ately after crossing the Suspension-Bridge. 



Coral-fauna : 



Alveolites septosa. 

 Syringopora cf. distans. 

 Lithostrotion Martini & muts. 



Brachiopod-fauna : 

 Seminula ficoidea and closely- 

 allied forms. 

 Orthotetes crenistria, mut. S. 

 Productus aff. hemisphericus. 



Cyathophyllum Murchisoni. 

 Clisiophyllum ( Carcinophyl- 

 0. 



Productus Cora, mut. I 

 Productus ' giganteus.' 

 Chonetes papilionacea. 

 Chonetes aff. comoides. 



A characteristic bryozoan in this subzone is Chcetetes (?) radians. 



Special f aunal characters : — 



Lithostrotion Martini, Seminulce, and Producti abound throughout. 



Chonetes -papilionacea and Syringopora sp. are common at re- 

 curring levels. 



Clisiophyllids occur sparingly from the base of the oolite onwards, 

 and are chiefly represented by Clisiophyllum 6. 



Orthotetes, Alveolites, and Cyathophyllum Murchisoni are rare. 



Productus i giganteus y becomes abundant at the top of the 

 subzone. 



Productus Cora, mut. S 2 , attains its maximum in the Seminula- 

 oolite. 



Productus aff. hemisphericus gradually increases in numbers. 



