237 
The Secretary then took up his parable, and with the geological 
map spread out on the grass, spoke of the geological features of 
the district. Alluding to the Mendip hills, which formed the 
base of the Bristol and Somerset Coal field, they were now, he 
said, standing to the south of this, with the ancient barrier of 
these hills shutting them off from that field, but might not 
another roll of these Coal Measures be lying beneath their feet 
between the Quantocks on the south, and these hills on the 
north? Possibly : but if so it must be won at a great depth, for 
the Secondary formations on the south side where they were 
standing were of much greater thickness than the same on the 
north ; the Triassic, Liassic and Oolitic rocks being estimated by 
thousands on this side instead of by hundreds of feet on the 
other. With regard to the Knoll on which they were standing, 
some 475 feet above the sea level—having passed from the 
alluvial plains of the Moor, they had gradually walked over the 
Lower, Middle and Upper Lias beds, forming platforms dis- 
cernible from a long distance, until they reached the main mass 
of the Knoll itself, which consisted of the Midford sands, capped 
by a small exposure of the Cephalopoda bed of the Inferior 
Oolite according to the recent survey. Glastonbury Tor, which 
they could see in the distance to the height of 500 feet above sea 
level, was of similar formation, but capped only by the sands. 
Both were once islands in the ancient seas, and bore traces of 
great denudation ; indeed should there be a rise of the tide from 
any unforeseen cause, to the height of some 20 feet above its 
ordinary level, the whole Moor might even now be covered by the 
sea water as it was formerly, and the various knolls seen rising 
as of yore islands from the mass of water. Before descending, 
attention was drawn to the state of the ground on top of the 
camp, pitted all over with irregular hollows, apparently the result 
of quarry explorations for stone. Query, whence came the lower 
Lias used in the churches on either side of the knoll? Not from 
here of course, but from some beds lower down in the formation. 
