574 Correspondence — Prof. Edward Hull. 



either in character, thickness, or succession of the Permians on the 

 opposite side of the Pennine Chain," I quite dissent from his way 

 of putting ray views, except in the matter of " thickness," which is 

 of very little importance in an inquiry of this kind. On the con- 

 trary — both in Yorkshire and Lancashire — we have Upper Permian 

 beds represented by Magnesian Limestones with identical fossils, 

 and Lower Permian beds, consisting of soft sandstone of very great 

 thickness at Stockport and elsewhere, close to the edge of the Pen- 

 nine Chain. 



I cannot consent " to omit from consideration " the " Lower Per- 

 mian Sandstone " as Mr. Wilson wishes us to, on the ground that 

 " its true horizon seems doubtful." There is really no such doubt, 

 as, both at Manchester and Stockport, these sandstones have been 

 proved to rest unconformably on the Coal-measures on the one hand, 

 and be overlain by marls with limestone containing Permian fossils 

 on the other. Then, again, both of these formations are unconform- 

 ably overlain by the New Red Sandstone, as was clearly proved by 

 the borings at Heaton Mersey, below Stockport, and other places. I 

 must repeat, therefore, that there can be no question that the Lower 

 Red Sandstone of Stockport is the representative of the Lower Eed 

 Sandstone of Durham and North Yorkshire ; for they agree both in 

 position, character, and their relations to the adjoining formations — 

 both above and below. 



If this be so, I would ask Mr. Wilson how can he account for the 

 fact that this Lower Permian Sandstone is remarkably free from 

 fragments of Carboniferous rocks, or, indeed, of rocks of any kind, if 

 it was deposited at the base of a Carboniferous ridge ? 



As I have already shown, in the paper just quoted, the differences 

 in the characters of the Permian rocks in the N.W. and N.E. of 

 England are those of degree rather than of kind, and may be ac- 

 counted for on the law, or principle, which will be found to charac- 

 terize many natural groups or formations ; namely, the development, 

 in opposite directions, of calcareous and sedimentary strata. 1 The 

 real Carboniferous barrier of this period lay below the Cheshire 

 Plain, reaching the Carboniferous tract along the valley of the Dane, 

 near Bosley. To the north and south of this ridge the Permian 

 beds were connected more or less across the country. 



In conclusion, I cannot admit that the absence of such a thin and 

 local formation as the Marl-slate of the North-east of England in 

 Lancashire or Cumberland is of much importance in this inquiry. 

 I can point, on the other hand, to real Magnesian Limestones at Skil- 

 law Clough, and two or three other spots, as evidences of connexion 

 between the east and west. I do not therefore see sufficient reason 

 for altering the conclusion to which I have already arrived, while I 

 admit that both points of view — that held by Mr. Wilson, and by 

 myself — have their difficulties. Edward Hull. 



1 Ibid, p. 176. 



