THE AVONIAN OF THE AVON GOROE 
115 
Corals : — 
In addition to Lithostrotion and Syringofora which are 
extremely abundant, Carcinofhyllum and Alveolites occur 
somewhat sparingly, and Cyathoyhyllum has been recorded 
from the uppermost beds in two localities only. These are 
the only corals found in this subzone throughout the South- 
Western Province ; ZapJirentis, Caninia, Dihunoyhyllum, etc., 
being all absent. 
Brachiopods : — 
Productus hemisphericus (abundant). 
Prod, corrugato-hemisphericus (abundant). 
Prod, giganteus (from the uppermost beds only). 
Prod, punctatus (rare). 
Chonetes cf. papilionacea (abundant) and G. aff. comoides. 
Orthothetids (rare). 
Cyrtina carhonaria and var. (especially abundant near the 
base). 
Athyris (rare). 
Seminula ficoides and vars. (abundant). 
The above list comprises all the Brachiopods which have as 
yet been recorded from the S2 subzone throughout the South- 
Western Province. Spirifer, Syringothyris, Schizophoria and 
Leptaena are all absent and, although Seminula is so remark- 
ably abundant, Athyris is very rare. 
The limited nature of the fauna points clearly to the existence, 
during XippQX- Seminula time, of very special conditions through- 
out the whole of the South-Western Province. 
[Recent work has added considerably to our knowledge of the 
area over which the S2-Phase extended. Mr. T. F. Sibly has 
shown that there is very little evidence of the development of 
a typical Sg in the Eastern Mendips, Dr. Wheelton Hind has 
discovered indisputable evidence of the presence of this Phase 
in North Wales, and work by Mr. E. E. L. Dixon and myself has 
shown that the peculiar ‘ pisolite ’ rock-type reaches the acme 
of its development in the Gower Peninsula. Hence it appears 
probable that the S2-Phase extended round the old Welsh land- 
