﻿192 DK. A. VATJOHAN ON THE PALJEONTOLOGICAL [May I905, 



Syringothyris cuspidata and Orthotetes crenistria are abundant 

 in those particular mutations which characterize the Zaphrentis- 

 Zone. 



Cliothyris glabristria and Meticularia an°. lineata enter, and 

 gradually increase in abundance. , 



Chonetes papilionacea occurs rarely, for the first time, near the 

 top of the subzone. 



Corals : 



Zaphrentis aif. Phillipsi is common in certain beds. 

 Syringopora 6 occurs rarely. 



No other corals have been recorded. 



Z 2 = Subzone of Schizophoria resupinata (besupinata- 

 subzone) . 



Where exposed in the Avon section: — 



Clifton side : The main Black-Bock Quarry (that is, that portion 

 of the present quarry which has been worked back to a con- 

 siderable distance from the line) not including the southern 

 end. (See Horizon y and Zone C, p. 193.) 

 Leigh Woods side : The upper part of Quarry 2. 



Special faunal characters: — 

 Erachiopods: 



Cliothyris Boyssii, Spirifer afT. clathratus, Camarotoechia 

 mitcheldeanensis, Leptena analoga, and Chonetes cf. crassistria 

 are nowhere common. 



JSyringothyris cuspidata and Orthotetes crenistria are abundant 

 in the mutations typical of the Zaphrentis-Zone. 



Bhipidomella aft'. Michelini is common, but has passed its acme. 



Cliothyris gldbristria and Schizophoria resupinata reach their 

 maxima, and are prolific. 



Chonetes cf. hardrensis teems in certain beds, where it is more 

 and more frequently associated with Ch. papilionacea. 



Productus cf. Martini becomes rare, and is replaced by a 

 larger form closely allied to Pr. semireticidatus. Productus aif. 

 Cora, mut. Z, is rare. 



Syringoihyris aff. laminosa makes its entrance in this sub- 

 zone. 



Corals : 



v 7 4- i«? D7-77- • fteem throughout the subzone, 



Zaphrentis air. Plulkpsi -, i - 1 • • ^ 



nr^n ™ * . < and reach their maxima near the 



Zaphrentis an. cornucopice , * ., 



Amplexus cf. coralloides enters towards the top, and quickly 

 attains its maximum. 



Caninia cylindrica and Michelinia occur rarely in the very 

 topmost beds. 



Syringopora 6 is common at certain levels. 



