NORTH STAFFORDSHIRE COAL-FIELD ORGANIC REMAINS. 343 



base of the thick ironstones of the middle measures ; but the circumstance was 

 overlooked, and such organisms were supposed tobe confined to a certainhorizon, 

 defined by a bed of what is generally known as Stinking Coal, worked princi- 

 pally for furnace purposes in the Chiu'net valley, and finding its representative 

 in the little coal of Wetley Moor, and the thin seam of the Roaches, A careful 

 examination, however, of beds exposed by sinkings at Longton, led to the 

 discovery of fossils in the shales of a thin unworked coal called the Bay Coal, 

 lying nearly 4000 feet above the Stinking Coal, which corresponded in every 

 essential degree with the fossUs of that weU known bed in the Churnet vaUey. 

 It is, however, a remarkable fact that, although some of the organisms of 

 these widely-separated beds belong to the same type, there is a marked 

 difference in their mode of occurrence, and in the number and variety of both 

 the genera and species they represent. The Stinking-Coal MoUusca consist 

 of immense numbers of compressed Aviculo-pecten, Goniatites, and Posi- 

 donia, with Lingula and Orthoceras. In the Bay Coal shales Fosidonia 

 appears, so far as is known, to be absent, but Avicido-pecten is represented 

 by two species, accompanied by interesting examples of Goniatites, Linr/ida, 

 and Orthoceras. Here, however, come for the first time in this field, Spirifer, 

 Ctenodonta, Macrocheilus, Natieopsis, Nautilus, and Loxonema, and with 

 these are associated at least two species of Biscina. Again, below the Bay 

 Coal, in the Prior's-field ironstone, Discina is now found to be accompanied 

 by Linrjula, but hitherto none of the other foi-ms alluded to have been 

 foimd associated with them. Up to the present moment no instance has 

 come imder notice of the direct commingling of Anthracosia or its congeners 

 with either of the shells referred to. In the case of the Bay Coal, there is 

 immediately above, and in contact with the Lingula shales, a thin band of 

 ironstone, containing Anfhracomya PMIlipsii ; but the separation of the or- 

 ganic contents of the two beds is as complete as if hundreds of feet of strata 

 divided the period of deposition of the one from that of the other. Equally 

 marked and distinct are the Aviculo-pecten and Goniatite beds of the lowest 

 measures ; wherever they occur they are found in immense numbers, generally 

 compressed and confined to a well-marked hne of deposit, never exceeding 

 16 inches in thickness, and in no case becoming incorporated with the 

 shales immediately above or below it. This peculiarity is further illustrated 

 by a thin band of lean ironstone, lying about 50 feet above the Stinking 

 Coal in the Churnet valley, in which were discovered last year remarkably 

 fine examples of Avindo-pecten papyraceus. The Froghall hasmatite, in 

 some instances of thinning out, forms the matrix of Anthracosia acuta, but 

 beyond this its organic contents are remarkably scanty and obscure. Below 

 this bed, at the base of what, however, appears to be the shales of the first 

 grit, occurs another band of haematite, which, in its line of outcrop on the banks 

 of the river Churnet near Consall, is overlaid by a nodular bed of earthy iron- 

 stone, containing Goniatites and Posidonia ; and in the shales by which it is 

 covered, these fossils are accompanied by Aviculo-pecten and Orthoceras. 

 It is therefore a matter of some interest that the lowest or first fossiliferous 

 deposit of the true coal-measures of this field is characterized by a moUusk 

 regarded as of freshwater origin, which, existing dm-ing the deposition of 

 the thick intervening chocolate-coloured shales, ultimately gave place to the 

 marine forms of the Stinking Coal shales, and with its congeners alter- 

 nated with Avicido-pecten, Goniatites, and Posidonia to the base of the 

 more productive measures of the great Pottery coal-field. Beyond this, up 

 to the Prior's-field ironstone, 2500 feet above it, no known break occurs in 

 the distribution of the inferred freshwater mollusks, but they spread outwards 



