NORTH STAFFORDSHIRE COAL FOSSILS. 189 



It contains great numbers of a small annelid (Spirorbis 

 carbonarius), and affords a valuable datum-line to the 

 underlying measures. Similar beds, but much thinner, occur 

 near the Newcastle tunnel, Hartshill, and Blurton, but 

 whether they represent distinct bands is not yet quite clear. 

 In the Warwickshire, Shropshire, and South Wales coal- 

 fields similar beds of limestone are found, and at Ardwick, 

 near Manchester, there is a bed much more largely 

 developed. This affords a clear proof that important 

 changes took place over a wide extent during <the forma- 

 tion of these coalfields. At Shelton Colliery the Gubbin 

 ironstone contains many fine specimens of teeth of several 

 species of fishes. Teeth of a rare reptile (Pteroplax cornuta) 

 (see plate, fig. 1) are occasionally found in this bed. 



Passing over a number of coal seams the shales of which 

 contain but few organic remains, we come to the Deep 

 mine ironstone, one of the richest stones in the eastern 

 part of the district. At Longton it is worked to a greater 

 extent than in any other part. It has a fine black lami- 

 nated shale, which contains many perfect fishes, of which 

 Pakeoniscus is the characteristic genus. It contains one 

 new genus (Cycloptychius) ; also fine specimens of Coelacan- 

 thus, Amphicentrum, and Acanthodes. Detached teeth of 

 Megalichthys and Diplodus are not rare, and occasionally 

 specimens of Sphenopteris Hoeninghausii and a new species 

 of pecopteris with serrated edges are found. At Shelton, 

 this bed does not appear to be rich in organic remains. 

 The Rusty mine and Chalky mine ironstones are rich in 

 several species of fishes. At Fenton, a fine jaw, teeth, 

 and a large portion of the head of a rare reptile (Pteroplax 

 cornuta) have been found in the latter bed. About 12 

 yards below this bed there is a bed of sandstone con- 

 taining mineral tar. 



