THE AVONIAN OP THE AVON GORGE 
113 
Fauna : — 
Corals : 
Caninia cylindrica, mut. S, Syringopora cf. reticulata. 
Lithostrotion Martini. Syr. cf. distans. 
Lithostrotion hristolense. 
Brachiopods : 
Productus d. 
Productus semireticidatus, mut. 
B r y o z o a : 
Heterotrypa cf. tumida. 
Gasteropods : 
Bellerophon, Loxonema, etc. 
Local detail: 
^ The rifle butts in the Great Quarry stand at the top 
of a dip face which slopes down to the floor of the 
quarry at its north end. Another dip face, lower down in the 
sequence, forms a second and larger slope behind the butts. 
The rocks are best examined from these two slopes which will 
be referred to as ‘ front slope ’ and ‘ back slope ’ respectively. 
The dendroid coral Lithostrotion Martini, which abounds 
throughout the Seminula-Zo-RQ, often builds up entire beds. 
The massive coral, Lithostrotion hristolense, is only abundant 
in a thick bed just above the ‘ back slope.’ Specimens were 
formerly obtained from a petroleum-stained patch at this level 
and are common in old collections, where they are usually 
labelled Lithostrotion aranea. 
Syringo'pora cf. reticulata is, locally, a valuable diagnostic 
fossil, as it is not known, in the Bristol area, above Si or below 
the Syringothyris-ZonQ. 
The subzonal coral, Caninia cylindrica, mut. Si, is only 
abundant in a thick bed a few feet above the ‘ front slope.’ 
Seminula ficoides is enormously abundant at frequent in- 
tervals throughout the Seminula-ZonQ. 
The shaley partings in the Si subzone are frequently crowded 
with crushed Seminulae and, resting immediately upon the 
Athyris cf. planosulcata. 
Syringothyris cf. laminosa. 
