282 



Reviews — Memoirs of Geological Survetj- 



For similar reasons the terms Upper, Middle, and Lower CoaU 

 measures have not been adopted ; since the positions of the- 

 palEBontological boundary lines or zones, which may give a definite 

 significance to the terms, have not been determined with accuracy. 



It is evident, as pointed out by Juices long ago, that as regards 

 the higher portions of the Coal-measures, North Staffordshire 

 presents the type-development for the Midlands. In that region 

 Mr. Gibson has established a definite stratigraphical sequence in 

 the comparatively barren strata which conformably overlie the pro- 

 ductive Coal-measures, and he has also proved that the same sequence 

 may be recognised in the other coalfields of the Midland area. 



The points of special economic interest are given in a separate 

 chapter, considerable attention being paid to the future development 

 of the coalfield. 



The portion of the memoir descriptive of the Cheadle Coalfield is 

 largely a reprint from a separately published memoir on this small 

 coalfield by Mr. G. Barrow.^ Since the publication of that memoir 

 the prediction there made that the Dilhorne Coal underlay the 

 Delpbouse area has been verified by actual sinking. 



The formations and groups of rock in North Staffordshire are 

 arranged in the following descending order of sequence, the sedi- 

 mentary and igneous rocks being kept distinct : — 



TABLE OF FORMATIOiS'S. 

 Sedimentary. 



Pleistocene | EecentandPost-Glacial... Alluvium, peat, and river gravels. 

 AND Eecent. (Glacial ... ... ... Clays, sands, gravels, and erratic blocks. 



f Keuper ... ... ... Marl, soft flags, and building-stones. 



\ Bunter ... ... ... Sandstones and conglomerates. 



'Eed sandstones and marls (Keele group). 

 Grey sandstones and marls (Newcastle- 

 under-Lyme group). 

 Tti,. Po/i „„.i ri.„,, «„.,-„„ ) lied marls and green grits (Etruria marl 

 group). 

 Grey shales and marls, thin coals, and 

 bands of Blackband ironstone (Black- 

 band group). 

 Grey shales, sandstones, and marls, 

 with numerous seams of coal and clay 

 ironstones in upper portion. 

 Grits and shale. 

 Grits, crowstones, and shales. 

 ( Massive limestone, with shale and thin 

 \ beds of limestone at top. 

 Igneous. 



A. Interstratified, or contemporaneous with the formation among which they lie. 



Tuils and agglomerates in the upper part of the Carbouiferous Limestone. 



B. Intrusive or subsequent in date to the formations among which they lie. 



Basalt and dolerite in dykes traversing the Carboniferous and Triassic formations. 



The district occupied by the coalfields of North Staffordshire is 

 situated at the south-western termination of the Pennine Chain — so 

 well known as forming the backbone of England. This elevated tract, 

 though consisting in the main of one great anticlinal uplift, of which 

 the core is composed of the periclinal Carboniferous Limestone massif 



' See footnote ante. 



Trias 



S i 



The Eed and Grey Series 



The Grey or chief Coal- 

 bearing Series 



Millstone Grit 



Pendleside Series 



Carboniferous Limestone 



