296 JR. D. Vernon — The Loicer Coal-measures 



North Staffordshire. In this area it is difficult to define the upper 

 and lower limits of the group, owing to the replacement of part of the 

 sandstones by sandy shales, but even so far south as Euddington, 

 ■where the ' flags ' are wholly wanting, the sandstones are still quite 

 coarsely grained. 



The Alton Coal. — With the possible exception of the area south-west 

 of Chesterfield (10), this coal, with its accompanying marine bed roof, 

 is persistent throughout the Derbyshire Coalfield into Yorkshire, 

 where it becomes the well-known Ganister or Halifax Hard Coal, 

 which invariably has a marine bed roof. 



The correlation of this coal with the Bullion Coal of Lancashire and 

 with the Crabtree Coal of North Staffordshire is now well established, 

 and is regarded as strong evidence for the formation of the Coal- 

 measures of the Midland Counties in one basin of deposition. 



In Yorkshire the Ganister Coal has been extensively worked as an 

 engine coal. It is interesting to notice that its equivalent in this 

 area, the Alton Coal, possesses identical properties, being a pyritous, 

 quick-burning, good coking coal of variable thickness, used in the 

 past mainly for engine purposes. 



The Belperlaivn Coal. — This coal, with its underclay, rests im- 

 mediately upon the top of the First Grit. Towards the south it thins 

 away (see Fig. 2), and, by the intercalation of shale bands, deteriorates 

 in quality until at Ruddington it contains only 10 inches of coal.^ 

 This seam is the equivalent of the "thin coal and underclay" which 

 is constantly found on the top of the First Grit of the Yorkshire and 

 Lancashire Coalfields. 



2. The Southerly Attenuation of the Coal-measures. 



Figs. 1 and 2 illustrate the general southerly decrease in thickness 

 of these lower measures of the Yorkshire Coalfield. Fig. 2 shows that 

 this attenuation is most marked in the measures below the Alton Coal. 

 It is accompanied by a gradual and progressive loss of the associated 

 sandstones and thin coals, until at Ruddington the measures between 

 the Alton and Belperlawn Coals consist of only 32 feet of fireclay and 

 shales. A similar attenuation occurs in the equivalent measures of 

 the Cheadle Coalfield of North Staffordshire. These facts afford strong 

 confirmatory evidence that in this area and for these lowest measures 

 the old rocks flanking the Charnwood Range were part of the southern 

 margin of deposition of that continuous sheet of Coal-measures of 

 which the Lancashire, Yorkshire, and North Staffordshire Coalfields 

 are the remains. 



List of Fossils from thf, Lower Coal-measures of Nottixghamshire 



AND Derbyshire. 



Calamites sp., cf. schutzei, Stur. Crossotheca sp. 



C. sp., cf. varians, Sterab. Lepidodendron aculeatum, Sternb. 



Gordaites sp. Z. lycopodioides, Sterab. 



Sphenophyllmn cuneifolium, Sterab. Lepidophloios sp. 



Stigmaria ficoides, Sterab. Lepidostrobus sp. 



Sigillaria sp. Carbomcola robioita, J. de C. Sow. 



1 Nevertheless, the sinking- at the Oakwell Colliery, Ilkeston, is being continued 

 to tbe Belperlawn Coal. 



