Vol. XXviii.] PALEONTOLOGY OF LANCASHIRE COAL MEASURES. 625 



The remains consist of ribs, vertebrae and (?) shoulder 



girdle. 



Impression of ribs and vertebrae from Bastard Cannel of 

 Cliviger near Burnley. (W. 1159, e. coll. Wild, M.M.) 



Having enumerated the fossil fauna of the Middle Coal 

 Measures, and indicated the horizons and locaKties in which 

 each species occurs, it is now necessary to consider the 

 faunal development of each horizon, by which the range 

 of each species can be determined, and the data made 

 readily available to the needs of the practical miner and 

 field geologist. 



It will be noted that undetermined species of most genera 

 are indicated in the range columns. 



The need to record the genus, where the species is yet 

 unknown, arises from the fact that frequently examples of 

 the genus are recorded from an horizon from which no 

 known species has yet been obtained. An example will 

 make this clear. Sphenacanthus sp. is recorded from the 

 Royley or Arley Mine of the Oldham, Barnsley, and 

 Ashton-under-Lyne district, but no known species. 



Sphenacanthus hybodoides does occur in the Two Feet 

 and Pomfret Mines of Bardsley. Did we fail to record 

 Sphenacanthus sp. from the Royley Mine, it would naturaUy 

 be assumed that the genus was restricted to the two seams 

 mentioned. In tabulating the range of species, it has been 

 found necessary to divide the coalfield into districts, and 

 deal with the faunal horizons of each separately. The 

 districts are as follows : — Burnley, Bolton, Wigan, and 

 Bardsley, Oldham and Ashton-under-Lyne. 



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