638 EDWABD HULL ON THE CLASSIFICATION 



Anthracosia, Productiis carbonarius, P. semireticulatus, and Strep- 

 torhynchus crenistria, is considered to be the representative of the 

 Chance Pennystone of Coalbrookdale, and is included in the Middle 

 Coal-measures. 



Notwithstanding the freshwater conditions that appear to have 

 prevailed throughout the great mass of the Coal-measures of Prance 

 and Belgium, brackish-water or estuarine conditions, consequent 

 on slight depressions below the sea-level of the period, occurred at 

 several intervals, so that out of twelve fossiliferous stages described 

 by MM. Cornet and Briart five contain C'ardinia and Posidonomya. 

 In the 12th stage marine fossils occur which M. Charles Barrois 

 assigns to the zone of " the Chance Pennystone " of Coalbrookdale*. 

 The same observer has discovered Productiis carbonarius in " le gres 

 des Plaines" in the Boulonnais at the base of the Coal-formation, 

 which he considers as probably representing the Millstone Grit of 

 England. 



(3) Germany. Silesia. — In August of 1862 the attention of 

 Prof. Ferd. Homer was called to the existence of marine shells at 

 two collieries in Upper Silesia, in strata of shale lying near the base 

 of the productive Coal-measures of that district. The beds contain- 

 ing these fossils consist of dark shales about 100 feet in thickness, 

 and upon further examination yielded a large number of forms, de- 

 scribed and figured in Dr. Homer's paper f- They are as follows — 

 Phillipsia (sp. inc.), Orthoceras undatum, 0. dilatatum, 0. telescopio- 

 lum (n. sp.), Nautilus subsulcatus, Nautilus concavus, N. nodoso- 

 carinatus (n. sp.), Goniatites diadema, G. Listeria Bellerophon XJrii, 

 Littorina obscura, Anthracosia ? (n. sp.), Schizodus sulcatus, Leda 

 attenuata, Nucula gibbosa, Area Lacordairiana, Pecten (sp. inc.), 

 P. interstitialis, Productus longispinus, P. semireticulatus, P. pustu- 

 losus, Orthis resupinata, 0. crenistria, Lingula mytiloides, Piscina 

 nitida, Poteriocrinus, and plants — Noeggerathia, Catamites, Trigono- 

 carpum. Dr. Homer very aptly points out the resemblance of this 

 fauna to that of the Pennystone beds of Coalbrook Dale, described by 

 Professor Prestwich, and to that of the Gannister beds of Yorkshire, 

 described by the late Professor Phillips. There can, in fact, be no 

 doubt whatever that the beds in which they occur are the represen- 

 tatives of those just named. Out of the species above enumerated 

 there are no less than 9 which are known as occurring in the Gan- 

 nister-beds in the British Isles, viz. Phillipsia (genus), Nautilus 

 concavus, N. subsulcatus, Goniatites Listeria, Littorina obscura, 

 Schizodus sulcatus, Productus semireticulatus, Orthis resupinata, Lin- 

 gula mytiloides, and Piscina nitida. Here again we find representa- 

 tives of the genus Anthracosia associated with marine forms. 



(4) Westphalia. — The marine zone at the base of the productive 



* Loc. supra cit. pp. 225, 226. 



t Supra cit. 



\ This may be considered the characteristic shell of Stage E in Lancashire, 

 Yorkshire, and Derbyshire. The species of Phillipsia is probably pustulata, 

 which occurs (as we haye seen) in the beds of this stage at Castlecomer in 

 Ireland. 



