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61 
PHYSICAL DISTURBANCES. 
In former papers contributed to this Society the writer has 
entered so fully into the great physical disturbances which form 
so marked a feature in the Somersetshire Coalfield, that it is only 
necessary to refer to them here for the purpose of comparing them 
with the state of things which prevails on the Continent. 
The Coal Measures of the S. of England having been 
gradually formed by successive accumulations of vegetable 
growth, followed at successive intervals by submergences, and 
deposits of a different kind, were at length broken up by an 
extended elevation of the older rocks reaching from Pembroke- 
shire to Frome. 
This great axis of elevation, known in this neighbourhood as 
the Mendip Hills, must, at the close of the Coal Measure period, 
have formed an elevated mountain chain, the height of which 
ean only be judged from the thickness of strata since denuded 
from its summit, which cannot have been less than 12,000 feet ; 
and the effect of this great upheaval on the adjoining Coal 
Measures led to the most remarkable physical disturbances to be 
met with in this country. The Carboniferous Limestone and Mill- 
stone Grit between Mells and Ashwick were raised into a vertical 
position—if, indeed, they were not folded over—and for a distance 
-of five miles on the Northern flank of the Mendips, the Coal 
Measures were completely overturned, carrying with them those 
isolated masses of Mountain Limestone and Millstone Grit at 
Luckington and Vobster, to which Mr. Winwood has again 
-ealled attention to-day. The strata of the Vobster and Nettle- 
bridge Valley were thrown into a series of contortions, and the 
‘Coal Measures in the interior of the basin were thrust bodily 
forward to the N., forming the overlap fault of Radstock. 
So stupendous have these physical disturbances been that 
human ingenuity has been largely exercised of late years in 
endeavouring to get rid of them or explain them away ; but, if 
any doubt on the subject yet lingers in the mind of anyone, it is 
