188 NORTH STAFFORDSHIRE COAL FOSSILS. 



The coal-measures of North Staffordshire have been 

 divided by Mr. Smyth into four distinct parts as follows : 

 First, the upper measures down to the top Red mine iron- 

 stone, representing a probable thickness of 1,000 feet. 

 Second, the Pottery coal and ironstone measures down to 

 the Ash or Rowhurst coal, from 1,000 to 1,420 feet in 

 thickness. Third, lower thick measures, including the 

 Winpenny coal, thickness from 1,400 to 2,400 feet. Fourth, 

 lowest measures, including the Wetley and Biddulph coal, 

 probably 800 to 1,000 feet. The -whole form an aggregate 

 thickness of from 4,200 to 5,620 feet. 



The upper measures contain many fossil plants. Very 

 fine specimens of Stigmaria occur in the Red mine and 

 Bassy mine ironstones. Fish remains are rare, being almost 

 confined to detached teeth of which Diplodus gibbosus, Ag., 

 is the most common. The most characteristic shell is 

 Anthracomya Phillipsii, immense quantities of which are 

 found in the ironstones. 



The second division contains between forty and fifty 

 seams of coal of an aggregate thickness of fifty yards, and 

 seventeen or eighteen bands of ironstone. It is somewhat 

 remarkable that the principal ironstones are all found in the 

 upper division of this coalfield. In the South Staffordshire 

 and Derbyshire coalfields they occur in the lower divisions. 

 The only beds of ironstone of importance in the lower thick 

 and lowest measures are the Cockshead and the valuable 

 haematite of the Churnet Valley. 



In this division we find a remarkable bed of fresh-water 

 limestone, about 2 feet 6 inches thick, which is generally 

 found about twelve yards above the Bassy mine ironstone. 



