328 Correspondence. 
the Hundred of Yale, along the course of the great fault, past the 
broken limestones north of Cyrn y Brain and the division between 
the Denbighshire and Flintshire coal-fields to the plains of Cheshire : 
he will find the level beds of New Red Sandstone sweeping undis- 
turbedly across the course of the fault, and resting in one place upon 
Permian beds, in another on Coal-measures, and in another on the 
Millstone Grit. 
Let Lim walk into the pleasant Vale of Clwyd, and he will find the 
remains of the Carboniferous Limestone, which sweeps round the 
head of that valley in a beautifully symmetrical synclinal curve, 
covered in the centre of the valley by horizontal beds of New Red 
Sandstone. The Millstone Grit and the Coal-measures which once 
spread over that Carboniferous Limestone had been all swept away 
before the time when the New Red was deposited upon it. 
What became of the materials would be a wild speculation even to 
guess at. Limestones would of course be redissolved and restored 
to the Ocean from which they were originally derived. ‘They may 
have been resolidified and redissolved half a dozen times since then. 
The sandstones of the Millstone Grit may have entered into the 
composition of the New Red Sandstones. The Coal-measure clays 
may have been used up to form beds which have been destroyed and 
left no trace of their existence. Some of the materials may perhaps 
have ultimately entered into the compostiion of the Lias or other 
clays of the Oolites. Quien sabe ? J. Bente JUKES. 
To the Editor of the GEOLOGICAL MAGAZINE. 
Sirn,—In No. X. of your Magazine (p. 181) there appeared an 
abstract of apaper by Mr. Thomas Smyth, ‘ On the Upheaval of the 
Shores of the Firth of Forth during the Human Period ; with a 
notice of the recent discovery of flint weapons at Marionville 
(between Edinburgh and Portobello).’ 
Mr. Smyth states that he found ‘ Oyster-shells for a distance of 
a quarter of a mile from the shore, to a height of about 43 feet 
above the level of the sea...... beneath a stratified deposit 
of sand and gravel;’ and that he ‘had traced the same stratum, 
though devoid of shells | the italics are mine |, to a height of a hundred 
feet.’ Had Mr. Smyth looked into the writings of those who hold that, 
on the shores of the Forth, no evidence is apparent indicative of a 
recent rise, he perhaps would be convinced that the oyster-beds are 
storm-raised, and the sands above them not marine, but blown sand. 
Mr. Smyth goes on to say, ‘I then, in the second place, mention the 
known upheaval of at least 25 feet since the time of the Roman occu- 
pation.” If Mr. Smyth, or any of your readers, will peruse a paper 
which I read before the Royal Society of Edinburgh on the 21st April, 
1862, and published in the 16th volume of the ‘Edinburgh New 
Philosophical Journal,’ entitled ‘On the Danger of Hasty Generaliza-~ 
tions in Geology,’ he will find that I have proved Mr. Geikie’s views 
fallacious on this point, as that gentleman has not yet disproved 
my arguments. Further, if Mr. Smyth will honour me with a 
