THE AVONIAN OF THE AVON GORGE 
111 
Corals abound : 
ZajpUrentis (both species), Caninia, Amplexus, Michelinia, 
Syringopora. 
Local detail : 
Horizon y is represented by the massive bed which immed- 
iately underlies the /umwosu-dolomites at the extreme southern 
end of the Black-Rock Quarry. Sections and weathered calices 
of Caninia cylindrica can be seen in the rock faces, and Zaph- 
rentis is extremely abundant. 
Syringothyris-ZonQ : C = 
Ceneral characters of the zone in those areas in which 
the standard conditions obtained : — 
Lithostrotion is typically absent and Caninia abundant. 
Fauna: — 
Corals: 
Michelinia cf. megastoma can be found throughout. 
Cyaihophyllum is especially characteristic of the upper half. 
Zaphrentis aff. Phillipsi and Zaphrentis aff. cornucopiae pass 
up from the Zaphrentis-Zoiie below, but are only abundant in 
the lower half of the Syringothyris-Zone . 
Brachiopods: 
Syringothyris cf. laminosa and Syringothyris cuspidata are 
characteristic fossils. Chonetes cf. comoides and papilionaceous 
Chonetes crowd certain beds, especially in the lower part of the 
zone where they are associated with equally abundant speci- 
mens of the C mutation of Orthothetes cf. crenistria. 
Gasteropods : — 
A large species of Bellerophon is very abundant in association 
with Cyathophyllum <t> in the upper part of the zone. 
Local detail: — 
Plates IV., Owing to the peculiar conditions of deposition, the 
V. and Va. Syringothyris-ZoiiQ in the Avon section exhibits 
very few of the above characters and, in fact, it is at the present 
