VOL. XIV.(1) | PRE-RHATIC DENUDATION 51 
the subsequent contortions of the strata must have pro- 
ceeded with imperceptible slowness. At first our area 
was probably on the northern slope of a simple anticlinal 
fold of great breadth,’ more or less levelled by wave-denu- 
dation, the summit of which was but slightly raised above 
the waves. Systems of drainage would be easily estab- 
lished on the slopes, and the streams would begin to 
excavate their channels. As the lateral pressure increased, 
this broad arch was gradually crumpled into a number of 
folds, the highest of which would probably coincide with 
the axis of the original anticline. But as the anticlines were 
raised across the direction of drainage, their motion was so 
slow that the rivers would cut down into them as fast as 
they arose. This explanation would also apply to 
faults,* which might therefore produce no effect upon the 
scenery. The main rivers would be fed by tributaries, 
whose direction would perhaps at first be decided by the 
synclinal depressions in the crust. 
The continuation of the process of elevation, accom- 
panied by sub-aerial denudation, resulted in the creation of 
a mountain chain, ranging to the east and west for unknown 
distances. We may call it the Mendip range, for the 
present Mendip anticlinal system doubtless constituted 
the summit ridge. We can hardly doubt that the chain 
was once much more lofty than at present; but we can 
form no estimate of the actual elevation, for, as the mass 
rose higher and higher, it was worn down by the increasing 
play of the forces of the atmosphere. At first, the slopes 
on either side of the summit-ridge were scored by rivers 
into deep valleys with steep sides, which rose here and 
there into subsidiary mountain peaks. But with the lapse 
of ages, the asperities of the surface were worn into rounded 
1 The Wealden dome may illustrate this stage of the folding. 
2 Such as the upthrust-fault seen at the foot of the Valley Road, Hotwells. 
