NORTH STAFFORDSHIRE COAL FOSSILS. 237 



was founded on specimens collected in the Pottery coal- 

 field. It is not rare in some localities. The species under 

 notice is broad in proportion to its length. It varies in 

 size, from an inch and a half to seven inches in length, 

 and from one inch to six inches in breadth. At the dorsal 

 and ventral margins the body of the fish is prolonged into 

 points, the ends being tipped with a short, strong bone, 

 curved at the point. The body is covered with scales " high 

 in proportion to their breadth : " near the margins they 

 are much shorter. The upper surface % of the scales is 

 ornamented with fine tubercles, which are more or less 

 confluent. The dorsal and anal fins are composed of slender 

 rays finely fringed at their extremities. The dorsal fin is 

 an exact counterpart of the anal fin. In none of our 

 specimens are the pectoral fins preserved, nor is their form 

 known. A row of triangular fulcral scales covers the upper 

 lobe of the caudal fin. The dentary apparatus of the fish 

 is of a complicated character and difficult to describe 

 Generally, however, the mandibles may be said to be com- 

 posed of a strong triangular bone which bears on its 

 margins six or seven conical tubercles, formed by the 

 prolongation of the bony tissue of the jaw. The maxillaries 

 differ somewhat from the mandibles : in both there is a 

 similar style of tooth. For a detailed description of the 

 jaws, together with their microscopical structure, we must 

 refer our readers to Dr. Young's paper (op. cit.) 



Position and locality : Knowles and Deep mine iron- 

 stones, Fenton and Longton ; Brown mine, Silverdale ; 

 Ash coal shale, Longton. 



