128 
THE AVONIAN OF THE AVON GORGE 
Climbing out of the cutting at its farther end, we find ourselves 
upon the bedding slope which bounds the main quarry on its 
northern side. This slope is formed by the lowest beds of the 
massive limestone series which constitute the Zaphrentis-Zone in 
the Avon Section. At this level several of the fossils which are 
characteristic of the Cleistopora-Zone occur in association with 
a typical Zaphrentis-tdiundi, and it is to this fact that the level 
owes its differentiation as Horizon /3. 
The following Corals and Brachiopods have all been collected 
from Horizon in Quarry 1 : — 
(а) Brachiopods which may be considered to be characteristic 
of the Cleistopora-Zone : — 
Spiriferina cf. octoplicata. 
Chonetes cf. Buchiana. 
Athyris Royssii and its variant, mut. 
Camarotoechia mitcheldeanensis . 
(б) Prodmtus cf. hurlingtonensis, mut. /3 is common and may 
be considered to be equally indicative of the uppermost part of 
K and the lowest part of Z. 
(c) Zaphrentis afE. Phillipsi, which by definition is diagnostic 
of the Zaphrentis -Zone, is less common in Quarry 1 than it is on 
the Clifton side of the river, in Press’ Quarry. 
(d) The general Zaphrentis -abssemhlage of Brachiopods which 
has already been specified in the description of the lowest beds 
of Quarry 2. 
Leaving Quarry 1, we must walk northward, along the towing- 
path, as far as the southern end of a good exposure by the side 
of the line. 
K,. 
Here the Ki sub zone is finely exposed and there is a satis- 
factory sequence from the normal development of Ki, down 
through the ‘ Mo^m/a-Phase,’ into the uppermost beds of the 
Old Red Sandstone. 
The rail-side section is, however, less convenient for work than 
