OP THE SWISS JURA AND ENGLAND. 



245 



The Pterocerian is, perhaps, the most important stage in the 

 whole Upper Jurassic series, since it forms by far the greater por- 

 tion of the high ground in this part of the Jura. Its thickness has 

 been estimated at 150 metres (492 feet), and it would appear as if 

 it was thickest in the southern part of the Jura, and thins out to 

 the north. On the whole, it presents much the same lithological 

 character in the district under consideration, but most of the beds 

 are poor in fossils. It has been divided into an upper and lower 

 substage. 



The Lower Pterocerian consists of a thick series of coarse greyish 

 limestones with some marls, the whole being usually poor in fossils. 

 The following zones have been made out in the Upper Pterocerian 

 (Jaccard, op. cit. p. 189) : — 



3. Yery compact lithographic limestones with Bryozoa. 



2. White saccharoid or crystalline limestone with Bryozoa, Nerincea and 



Diceras (small). 



1. Greyish marls, rich in fossils. 



In the ' Combe Grede ' the following section was observed below 

 the Yirgulian : — 



3. A thick series of greyish limestones. 



2. Greyish, somewhat brecciated limestones, with Terebratula subsella, Ostrea 



solitaria, Nerincea bruntrutana, &c. 



1. Limestones with Nerincea. 



Similar massive limestones were seen near La Bauroe, Locle. 

 North of the road-tunnel, near Noirvaux-dessous, on the way to 

 Ste. Croix, a fossiliferous marly band in the Pterocerian is exposed, 

 and overlying it come some well-bedded, grey, very compact lime- 

 stones. Further south, near Jougne, the Pterocerian is quarried, 

 and the section shows about 24 feet of grey, very compact limestones, 

 with some brownish marly beds. Hocks of this age are also worked 

 near Soleure, and the fossils obtained from the quarries at St. 

 Nicholas (north of Soleure) include remains of Turtles and other 

 Reptiles and of fish. 



The following section was seen in one of the three quarries at 

 St. Nicholas : — 



• ft. 



4. Hard and somewhat porous limestone 5 



3. Greenish marls, with Pferoceras, Nerincea, Terebratula, Hemicidaris, &c. 4 



2. Hard, grey, compact limestone, separated by a thin marly bed from (1) 7 

 1. Thick bed of compact grey limestone. 



The other two quarries are opened in rocks having the same 

 lithological character as that at the base of the above section. 



The following fossils were obtained from the Pterocerian beds at 

 the localities named below 



