186 Correspondence—Professor Edward Hull. 
my paper “On the Upper Limit of the Essentially Marine Beds of 
the Carboniferous Series,” ! where this and the ‘‘ Ackworth rock ” 
are placed in my Carboniferous “Stage G.” It is therefore futile 
to controvert a point which has never been asserted, at least by 
myself. The Lower Red Sandstone of truly Permian age is an 
entirely different rock, both in geological position and character. 
Whether in Lancashire, Cheshire, or Durham, it is quite unlike the 
Upper Coal-measure Sandstones, and it never occurred to me to con- 
found the two together, as has been done by Mr. Wilson. Again, 
on referring to Professor Ramsay’s paper, ‘‘On the Triassic and 
Permian Rocks,” it seems to me that his statement refers in a large 
measure to the Upper Coal-measure Sandstones of Yorkshire and 
Derbyshire, above described; but in any case it will be found, on 
referring to the recently published 6-inch maps of the Durham 
District, that the Lower Permian Sandstone is distinctly marked at 
intervals along the margin of the Magnesian Limestone, under the 
designation of ‘Yellow Sand.” Besides, neither in the paper 
referred to, nor in the new edition of the “ Physical Geology of Great 
Britain” (1878), does Professor Ramsay throw any doubt upon the 
age of the beds represented in Lancashire by Mr. Binney and 
myself as of Permian age; and as regards the question under 
discussion this is the essential point. I repeat, therefore, that allow- 
ing for the distance by which they are separated, the Permian beds 
on either side of the Pennine Chain are sufficiently similar in posi- 
tion, character, and succession, to admit of the probability that they 
were originally continuous. This probability is reduced to a certainty 
by the identity of the fossils, of which Mr. Wilson seems to take little 
account. 
Mr. Wilson has referred to the results of the Scarle boring. Now, 
assuming the Carboniferous rocks which were reached to be those of 
the uppermost Coal-measures, and lying 2,000 feet (as Mr. Wilson 
supposes) above the highest beds cropping out along the borders of 
the Magnesian Limestone in Derbyshire, the distance being thirty- 
five miles, has Mr. Wilson calculated what the dip would be? 
He will find that about 1° will be a sufficient angle to bring them in. 
Now, I have never denied that the Coal-measures have a slight dip in 
relation to the Permian beds; but I say this may be an older tilting 
than that which upraised the Carboniferous rocks of the Pennine 
Chain. 
In reference to the general question of the relations of the Triassic 
and Permian rocks, I am at variance with the views of both your. 
correspondents. I think I may claim to have a much larger personal 
knowledge of the relations of these rocks over the central and 
northern counties than either Mr. Wilson or Mr. Teall, having spent 
from ten to a dozen years in mapping them. Knowing also the 
geology of Nottingham from personal examination, and from the 
observations of others, I have no hesitation in saying that the 
relations of these two formations in that very district prove distinctly 
their mutual unconformity. In other districts this unconformity is 
1 Quart. Journ. Geol. Soc. Nov. 1877, p. 627. 
