THE OLDEST MOUNTAIN IN ENGLAND. 
21 
The felspar rock and the granite closely resemble some of the 
Wrekin felstones and bastard granites ; but, however this may 
be, it is certain that the conglomerate, being a shore deposit, 
was derived from neighbouring land. It is clear, then, that 
some portion of the Wrekin mass — not necessarily, though very 
probably, the actual Wrekin wedge — was elevated above the 
Pre-Cambrian ocean. 
Figs. 1 & 2 are an attempt to represent two stages in the 
Pre-Cambrian history of the Wrekin. 
s.e. Fig. 1. n.w. 
Sea level. 
Beds of tuff and lava have been formed by volcanic eruption. They have 
been tilted up with a considerable dip to the north, which is represented as a 
slight dip to the north-west, the section being taken at right angles across the 
present axis of the hill. They have since suffered considerable denudation, 
and now form the bottom of the Pre- Cambrian sea. The Wrekin commences 
an independent existence by its separation from the main mass by two parallel 
faults, represented by the dotted lines. 
Fig. 2. 
S.E. N,W. 
The wedge is now thrust up above the level of the waves, disturbing the 
adjoining beds in its upward motion. A portion of the ridge forms an island, 
which furnishes pebbles to the sands (afterwards quartzite) which are ac- 
cumulating round its margin. 
Whether or not the Wrekin stood above the sea in the Cam- 
brian epoch is difficult to determine. In the Lower Cambrian 
