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A question naturally arises as to whether the Mendip ridge, 
| thus gradually passing downwards to lower levels in its, passage 
eastwards, may finally flatten out beneath the Secondary rocks, 
and cease to exist as an anticlinal ridge ; but the fact that at this 
the most easterly point, at which we have an opportunity of 
examining it, the Old Red Sandstone comes to the surface, and 
that both that formation and the Mountain Limestone lie at 
high angles, is direct evidence to the contrary ; and the existence 
of what appears to be a corresponding anticlinal in the Ardennes, 
has led to the conviction, that there must be a subterranean 
extension of the Mendip chain throughout the south-east of 
England. 
Being the most easterly loatdenanls indicating the southern 
margin of the Somersetshire coalfield, this bit of old Red 
Sandstone has an interest peculiarly its own, and it suggests 
many speculations as to the course of the same ridge eastward 
beneath the overlying rocks, and as to the prospects of 
finding coal adjacent to it of which at present we have no 
proof. In connection with this subject, however, it must be 
noted, that although the older rocks do not again come to the 
surface in the south-east of England, they have been proved by 
several borings in the neighbourhood of London. At Meux’s 
Brewery in London an important boring was put down in the 
year 1877, which, after passing in succession through all the 
Strata between the London clay and the lower Green-sand, 
entered certain mottled red, purple and green shales, which Mr. 
Etheridge had no difficulty in identifying as belonging to the Upper 
Devonian. They were met with at a depth of 1064 feet and 
_ Were cut through to a depth of 80 feet, the cores showing a dip of 
30° and yielding organic remains, which enabled Mr. Etheridge to 
4 speak with absolute certainty of their Geological age. 
_ Another boring was put down at Ware in Hertfordshire 
(about 20 miles north of London), which, after passing through 
‘Chalk and Green-sand to a depth of 196 feet, proved the Upper 
D 
