VOL. XIV. (1) MENDIP ARCHIPELAGO 63 
beyond. To the north were the Clifton, Clevedon, 
Walton, and Portishead Islands, whilst to the east of 
Clifton Isle may have been that of Kingswood. 
The outlines of the Clevedon, Walton, and the western 
extension of Clifton islands, are based upon the position 
of outliers of Keuper Conglomerate. The westward 
extension of Clifton Island seems to have only just been 
submerged. To the west was Clevedon Isle, north of 
this was Walton, whilst north of the latter were the 
Portishead islets, well known for their complicated 
geological structure. Clifton Island was indented on the 
east coast by Clifton Bay, and the marginal deposit which 
occupied its westward extremity is represented by the 
Bridge Valley Road section, and the small mass capping 
the limestone on the Somerset side of the river 
Avon. Excayated out of the Old Red Sandstone in the 
western shore was Sea Mills Bay. 
Many of the shore-lines were steep, and the cliffs much 
fissured; the latter was the case in all the Carboniferous 
Limestone islands. Wrington Island, from which 
we have taken our view, was low in the water. 
Trianguloid in shape, its eastern side was indented by a 
large bay, whilst to the west were probably the small 
Cadbury Isles. Wrington Island had also its Keuper 
shore deposit; and in the Winford district this deposit 
yields the reddle (or raddle), for which the locality is 
celebrated. At the present day tongues of ‘‘ Dolomitic 
Conglomerate” can be seen running far into the limestone 
mass; and their independence of more recent combes is 
worthy of notice." 
Keuper times were brought to a close by an invasion 
of the Rhetic sea. ‘‘ The epoch of the Avicula contorta 
zone marks the time when depression had proceeded so 
1 Prof. C. L. Morgan, F.R.S., “ The Geological History of the Bristol Area.” 
British Association Handbook, (1898), p. 34. 
