As a single instance--It is a provable and proven fact--as
you may see from Mr. Ramsay's survey of North Wales--that over a
large tract to the south of Snowdon, between Port Madoc and Barmouth,
there has been ground off and carried away a mass of solid rock
20,000 feet thick; thick enough, in fact, if it were there still, to
make a range of mountains as high as the Andes. It is a provable and
proven fact that vast tracts of the centre of poor old Ireland were
once covered with coal-measures, which have been scraped off in
likewise, deprived of inestimable mineral wealth. The destruction of
rocks--"denudation" as it is called--in the district round Malvern,
is, I am told, provably enormous. Indeed, it is so over all Wales,
North England, and West and North Scotland. So there is enough of
rubbish to be accounted for to make our New Red sands. The round
pebbles in it being, I believe, pieces of Old Red sandstone, may have
come from the great Old Red sandstone region of South East Wales and
Herefordshire. Some of the rubbish, too, may have come from what is
now the Isle of Anglesey.
For you find in the beds, from the top to the bottom (at least in
Cheshire), particles of mica. Now this mica could not have been
formed in the sand. It is a definite crystalline mineral, whose
composition is well known.
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