Correspondence—Mr. EF. Wilson. 93 
of the Carboniferous Period.” JI think the epithet “slight” is 
scarcely appropriate to a physical disturbance accompanied by 
denudation which determined the western boundary of the great 
Nottinghamshire and Yorkshire Coal-basin, and produced a north 
and south strike in the rocks which formed the crust of the earth 
during Permian times for many miles north of the place where 
Nottingham now stands. 
I maintain, then, in the absence of any direct evidence to the 
contrary, that we are bound to conclude that the north and south 
series of disturbances, like the east and west series, originated at the 
close of the Carboniferous Period. I say nothing about the age of 
the Pennine Chain as a barrier of high land; for all I know to the 
contrary, the anticlinal may have been planed away before the 
Permian Period, and the Permian rocks deposited continuously across 
it. The discussion as to the correspondence of rocks on opposite 
sides of the axis will throw interesting light on this question. 
I think the reason many geologists experience a difficulty in 
accepting the conclusion advocated in this letter is because they 
are still hampered by the fallacy that the Permian system is 
separated from the Trias by an important physical unconformability. 
9, Att Saints’ Srreer, NorrincHam. J. J. Harris TEALL. 
THE AGE OF THE PENNINE CHAIN. 
Srr,—At the time when Prof. Hull ascribed the elevation of the 
Pennine Chain to the interval between the Permian and Trias, a great 
hiatus was supposed to occur between the deposits of those epochs 
in this country. Now, however, we have learnt to believe that the 
great stratigraphical break comes, not between the Permian and 
the Trias, but between the Carboniferous and the Permian forma- 
tions. Nevertheless the faith in the older hypothesis seems to have 
created a bias on the question at issue that still lingers in the learned 
Professor’s mind. 
Prof. Hull only assails two of my arguments for a pre-Permian 
Pennine Chain ; it is these only, then, that I have to substantiate. 
The Yorkshire Coal-field was evidently completely formed anterior 
to the Permian epoch. ‘The prevailing easterly dip of the Coal- 
measures of Derbyshire and Yorkshire is appreciably greater than 
that of the Permians. (The reason why this difference in dip is 
not more decided in the vicinity of the Magnesian Limestone escarp- 
ment is that we are thereabouts beginning to reach the more central 
and therefore flatter lying portions of the Coal-basin.) 
The unconformable westerly overlap of the Coal-measures by the 
Permians, consequent on this greater dip, is, as illustrated in my 
paper,' decided enough. Prof. Hull is well aware of this; for in a 
paper “On a Deep Boring for Coal at South Scarle, Lincolnshire,” 
we find him expressing the opinion “that the Coal-measures of the 
Yorkshire and Derbyshire Coal-field, after extending for some distance 
with an easterly dip beneath the Magnesian Limestone, rise to the 
eastward, and ultimately terminate against the base of this formation.”* 
1 Grou. Mac. November, 1879. nh 
2 Proc. Inst. Civil Engineers, vol. xlix. part iii. 
