122 
THE AVONIAN OF THE AVON GORGE 
Lonsdalia, Lithostrotion irregulare and Gyathophyllum regium 
are the most abundant Corals. 
Brachiopods : 
Prodiictus latissimo-giganteus. Spiriferina cf. hiplieata. 
Choneti-Produchis. Martinia ovali-glabra. 
Spirifer hisulcatus. Athyris planosulcata. 
8p. planicosta. 
Giganteid Producti are the only Brachiopods which are abun- 
dant ; Spiriferids and Athyrids are rare. 
Bryozoa are not uncommon, and Catamites occurs in a thin 
grit band. 
Returning to Clifton Bridge Station, we will now commence 
our walk downstream along the towing path. 
The Dihunophyllum-Zone is poorly exhibited in the rail-side 
cutting, the beds which we have just examined in Rownham 
Quarry cropping out again at the southern end of this exposure. 
As we pass under the Suspension Bridge, the upper Seminula- 
Zone is well exposed in the clifi-face but presents no new points 
of special interest. 
In Nightingale Valley, which lies immediately north of the 
Suspension Bridge, the continuation of the Great Fault has been 
traced by Professor Lloyd Morgan. 
At this point, therefore, we enter upon the main Avon 
Section which includes, without a break in the sequence, all 
the zones, from the upper part of the Dibunophyllum-Zoxie down 
to the base of the Cleistopora-Zone and its conformable junction 
with the Upper Old Red Sandstone. 
D,. 
North of Nightingale Valley, the D2 beds form a high mural 
exposure which can be examined in Quarry 6. This quarry has 
been long disused, and will scarcely repay a short visit. Most 
of the fossils obtained at Rownham Quarry can also be found 
here, and Fistulipora cf. incrustans, a Monticuliporid character- 
istic of D2, is somewhat abundant, as are also the narrow-tubed 
