139 
length of section is laid open up to the superimposed limestone 
itself.* 
The Old Red Sandstone has been much flattened and 
thinned out in the neighbourhood of Yorkley, Soilwell Farm, 
and Lydney. 
If we construct a section from the Ebury River, in Mon- 
mouthshire, and continue it across the Forest of Dean towards 
the Severn, it will be seen that an anti-clinal line exists to the 
East of the outcroppings of the lower Carboniferous Limestone, 
and this same line of upheaval can be traced through the 
country for a considerable distance. 
Buckland and Conybeare considered that an anticlinal line 
passed the middle of the valley of the Severn, and that it was 
the cause of separating Dean Forest from the Bristol coal field. 
Murchison and Phillips concluded that the principal dis- 
turbance passed through Flintshire, Malvern, and then South- 
ward into Somersetshire, and that the elevation of the Malvern 
Hills, the Eastern portion of the Forest of Dean, and the 
greater portion, if not all, of South Wales, is due to this cause. 
The axis of the Malvern Hills is composed of Syenitic 
rock, and, according to the late Rev. W. 8. Symonds, it is eight 
miles long and half a mile in width.t It is very probable that 
this upheaval took place after the formation of the Lower 
Silurian beds, and may have terminated with the close of the 
Carboniferous period. The general effect produced must doubt- 
less have led to a series of elevations and depressions of the 
ancient sea level at a very early epoch. 
The upheaving force exerted on the Hastern side of the 
Forest must also have been enormous, for if we construct a 
restored section of the removed strata we should find that the 
top of the Carboniferous Limestone was raised more than 
5,500 feet above the present level of the water in the river 
Severn. The coal measures were consequently elevated as 
much as 8,000 feet above the same level, and the Old Red 
* See section by John Jones and W. C. Lucy, Vol. IV. Cotteswold Club. 
¢ See the works on the subject by Phillips, Hull, Rutley, and Callaway. 
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