THE AVONIAN OF THE AVON GORGE 
117 
Diagnosis: — 
Corals: 
In general, the abundance of Clisiophyllidan Corals is re- 
markably striking, both as regards species and individuals ; in 
particular, the predominance of the Dihunophyllum section and 
the occurrence of the Auloyhyllum section are noteworthy 
features. 
Narrow-tubed Lithos trot ions, such as Lithostrotion irregular e 
and L. Portlock% are the dominant forms of that genus. 
Brachiopods: — 
In general, the abundance of Producti, both as regard species 
and individuals, is a salient feature and in particular, the pre- 
dominance of the giganteid section and the entrance of the 
scabriculate and longispinous groups are the facts of chief im- 
portance. 
Of the true Spirifers, Sp. hisulcatus is the dominant species. 
= Subzone of Dihunophyllum 0. 
Diagnosis : — 
The entrance of Dihunophyllum and the predominance of 
those species of the genus which have a simple type of structure. 
The absence of highly specialized Clisiophyllids, such as 
Lonsdalia. 
The maximum abundance of Cyathophyllum Murchisoni and 
of Productus hemisphericus . 
Fauna : — 
Corals : 
, ’ ” '' Diphyphyllum. 
abundant. 
Lithostrotion irregulare. 
Lith. Martini. 
Liih. junceum. 
Syringopora of. geniculata. 
Syr. of. ramulosa. 
Syr. of. distans. 
Alveolites septosa (abundant). 
Cyclophyllum pachyendothecum 
(rare). 
Koninckophyllum d (common 
locally, e.g. at Sodbury). 
Campophyllum aff. Murchisoni. 
Cyathophyllum Murchisoni 
(very abundant). 
