NORTH STAFFORDSHIRE COAL-FIELD ORGANIC REMAINS. 45 



and pass downwards into the shales of the Millstone-grit and the grey iron- 

 stone nodules of the Carboniferous shales. In the Aviculopecten shales of the 

 Stinking Coal two or three at present undetermined species are imbedded, 

 but rarely in a well-preserved condition. The species of this bed are inter- 

 mixed with the marine shells, and appear to be different to those so largely 

 distributed amongst the beds of the upper thick measures ; and in no instance 

 have they been found in this deposit to pass above the line of the bone-bed 

 alluded to, where detached scales are largely intermixed with Lhujulce and 

 other organisms in a fragmentary condition. 



Towards the upper part of these lower beds a small species, tolerably per- 

 fect, is occasionally found imbedded in nodides of clay ironstone ; but, gene- 

 rally speaking, between this point and the shales of the Ash Coal, the base of 

 the upper thick measures, evidence of the existence of these fish seldom 

 occurs, except in the form of detached scales, scattered over the face of the 

 numerous intervening bone-beds. In the Ash-coal shales, however, they 

 appear in a more perfect form, and attain their maximum development in 

 the shales of the Deep Mine ironstone, 200 yards above it. This latter iron- 

 stone is at Longton, on the extreme western boundary of the proved measures, 

 1 foot 3 inches thick, and divided into four bands overlaid by a bed of black 

 shale, hard, clean, and easily split into thin slabs. As an ichthyolitic 

 depository it is one of the most interesting met with, and affords in addition 

 some curious data referable to the range of animal life in one distinct horizon. 

 This stone is worked at Longton, Fenton, Shelton, Berryhill, Sneyd Green, 

 Golden-hill, and other places, but not always under the same name. The 

 Longton bed is opened at two points communicating with each other, and from 

 the shales of these two workings have been collected, in a remarkable state of 

 preservation, specimens of eighteen genera, and about twenty-six species of 

 fish. One new genus, under the name of Cycloptychius, occurs in great 

 numbers and the most perfect condition ; but beyond the limits of the two 

 pits at Longton it has never as yet been known to pass ; and in each direc- 

 tion from this point, where the stone has been worked, the whole of its 

 organic remains die gradually out to a few detached scales and isolated teeth. 

 The restriction of the Palcronisci of this deposit to a definite range would 

 appear to indicate the prevalence of either deep or shallow water along this 

 particular line ; but it is in the character of its organic contents that this 

 peculiarity is the more observable ; the stone itself, where it has been 

 pierced, although showing a tendency to thin out towards its eastern out- 

 crop, retains over the greater part of the field a tolerably uniform thickness 

 and character. 



Of Coslacanthus there are two species, ft leptums and C. granulates, the 

 former being the more common, and of greater range. Detached scales are 

 met with in the Hydrate shales, and here and there in the fossiliferous beds 

 of the lowest measures, including the Stinking Coal shales. In the Wood- 

 head coal-shale of the lower thick measures, 0. lepturus is occasionally found 

 in a fair state of preservation, and also in the nedular grey ironstones inter- 

 mixed with the grey shales above it. More frequently, however, it occurs as 

 detached scales ; and in this form, wherever Palceoniscus is detected, both 

 Gcelacanthvs and Platysomus are generally in association with it. The Deep 

 Mine ironstone contains numerous fine specimens, and it not unfrequently 

 occurs in the Cockshead, Knowles, and Brown Mine ironstones and shales. 



Platysomus, of which there are two species, has a somewhat similar range ; 

 but in certain deposits, in different localities, each species appears to be a 

 characteristic feature. 



