Vol. 57.] THE UPPEE COAL-MEA8T7KES OP THE MIDLANDS. 259 



suppose that exactly the same law of sedimentation recommenced 

 after the break as had been in operation before it. 



The Black-Eand Series is thus seen to be palseontologically and 

 lithologically allied to the productive series : it also obeys the same 

 law of sedimentation as that under which the productive measures 

 were deposited. It is therefore not surprising to find that it shares 

 in all the faulting and folding which afiect the Carboniferous strata 

 in North Staffordshire. Without unduly forestalling the Geolo- 

 gical Survey memoir which will give the details of the structure, I 

 may say that every fault and all the synclines and anticlines affect 

 the higher measures as much as the underlying series. 



On the other hand, the map of the North Staffordshire Coalfield to 

 be published shortly brings out very clearly the great unconformity 

 between the Trias and the Carboniferous, and shows that many of 

 the faults which affect the latter do not affect the Trias, or do so in 

 a lesser degree. It is, therefore, evident that the chief movements 

 which have resulted in the tectonic structure of the North Stafford- 

 shire Coalfield took place in the great interval of time marked by 

 the hiatus between the Trias and the Carboniferous svstems. 



The Red Colour shown to be Original. 



As long as the Keele Sandstones and Marls were considered to be 

 of Permian age, the red colour was regarded as original, but when it 

 became evident that they belonged to the Carboniferous, the question 

 arose whether the colour might not be due to subsequent staining. 

 It will, therefore, not be out of place to say a few words on this 

 subject. 



The great thickness of the Xeele Series is in itself a strong argu- 

 ment against the colour being due to subsequent staining. Also 

 on the view of after-staining it is difficult to understand why at 

 Blurton, where the Keele Sandstone is faulted against the basal 

 beds of the Newcastle Series (p. 256), the former is of a deep red 

 colour and the latter pale grey or white, since both are equally open 

 and porous rocks. The fact that entomostracan limestones, or red 

 shales with entomostraca, invariably accompany the red colour, 

 shows that this marks conditions of deposition, and that the red 

 coloration is original. 



Summary. 



To summarize briefly the results obtained in North Staffordshire : 

 The upper barren Coal-Measures of North Staffordshire are capable 

 of a fourfold subdivision, the groups representing a definite 

 sequence of red and grey strata. Thin bands of limestone with 

 Spirorbis and entomostraca are developed throughout, and certain of 

 them occupy definite and constant positions. Though these attain 

 their maximum development in the barren series, they are not 

 unknown in the productive measures. Ked strata are at their 

 maximum thickness in the higher barren measures, but, although 



