1869.] HULL GEOLOGY OF CHESHIRE. 177 



On the other hand, the evidence which I am ahout to adduce seems 

 to show that the Permian rocks both of the North-west and North- 

 east of England were disconnected during their deposition from those 

 of the midland counties and Shropshire. Under this view, it will 

 be apparent that there are in reality only two types of Permian beds 

 in England, those of the north and those of the midland counties ; 

 though at first sight it might have been supposed there were three, 

 namely, those of the Salopian, Lancashire, and Durham or Yorkshire 

 types. 



Possible Causes of the typical DiFFEHEisrcES n^ the Permian for- 

 mations OYER the Salopian and Lancashire Areas. 



Having thus described the distinctive characters and range of the 

 two types of Permian beds in the tract of country under investiga- 

 tion, it now remains to inquire into the causes of this diversity of 

 character. As already stated, there appear to be three possible modes 

 of explanation. 



1. We might suppose that the beds of both types had been depo- 

 sited in the same basin, and that the differences in mineral and 

 stratigraphical character were due to differences in the sources of the 

 sediment. This explanation appears to me insufficient, as there are 

 no intercalations on either side. Considering the gTcat thickness 

 which this rock attains in North-east Cheshire (at least 1500 feet), 

 and the proximity of the two districts, it is strange that it should 

 not be represented by interstratification amongst the beds of North 

 Staffordshire, if the two areas were in communication, or, on the 

 other hand, that the beds of the Salopian type should not be repre- 

 sented by interstratification amongst those of the Stockport and 

 Manchester district. This explanation also fails to account for the 

 absence of the Upper Permian beds of Lancashire in the southern 

 area, a series of beds which, from their very nature, may be presumed 

 to have extended as far as the hydrographical boundaries would 

 admit. 



2. To suppose that the two types of rocks were not contempo- 

 raneous is still more unsatisfactory, and is not in accordance with 

 the relations which the beds in both regions bear to the Carboni- 

 ferous rocks on which they repose. These relations are precisely 

 similar. In some places there is (as it were by accident) con- 

 formity, in others, great discordance. To suppose that there are 

 two types of Roih-todt-liegende representing two successive stages 

 of this earliest period of the Permian group, is not in accordance 

 with observation in other districts. On the contrary, the beds of 

 the Salopian type must, I think, be regarded as representatives in 

 time of the Lower Red Sandstone of Lancashire, and both as repre- 

 sentatives of the Lower Permian stage, or Both-todt-liegende of 

 Germany. 



careous submarine mud -flats that lay off the coast of a Permian land-area ; the 

 Yorkshire fauna certainly existed further away in deeper water, and within the 

 limits of regular deposition of calcareous sediment." 



