552 Dr. C. Struchmann — The Jura of Hanover and England. 



ledge contain 19 species of the Hanoverian Upper Jura, namely, 1 

 Echinoid, 15 Bivalves, and 3 Gasteropods. 



a. Of these 19 species, 12 are observed in the Hanoverian 

 Coralline Oolite in general ; on the other hand, exclusively in 

 the Kimmeridge, 7 species, namely : — Ostrea Monsieliardensis, 

 Exogyra Bnmtrutana, Pinna granulata, Ceromya excentrica, Pleuro- 

 mya tellina, Natica Eudora and Lucina plebeia. 



On the other hand, 14 species occur in the Hanoverian Kimmeridge 

 in general, and only in lower beds 5 species. Of the latter, two species 

 ( Chemnitzia heddingtonensis and Lima prohoscidea) go down into the 

 Hersumer beds, while three species are peculiar to the Coralline 

 Oolite in North Germany, namely, Cidaris florigemma, PJiasianeUa 

 striata, and Ostrea deltoidea. Among the species which are found 

 both in the Kimmeridge and in lower beds, Lucina suhstriata must 

 also be mentioned ; this only attains the climax of its development 

 in the Kimmeridge. 



6. Of the 14 species which occur in the Hanoverian Kimmeridge, 

 12 appear in the Lower Kimmeridge (Astartian), while only 2 

 species {Pinna granulata and Natica Eudora) belong exclusively 

 to Upper Kimmeridge beds. It is true that the first-mentioned 

 12 species are not exclusively confined to the Lower Kimmeridge; 

 9 species ascend to a higher horizon. 



It appears, therefore, from this comparison, as indeed is indicated 

 by Blake, that the Kimmeridge Passage-beds also possess a mixed 

 fauna. But while in the case of the Supra-coralline beds the 

 downward relationships, i.e. to the Coralline Oolite, are prepon- 

 derant, the fauna of the so-called Passage-beds decidedly bears 

 rather the character of the Kimmeridge formations, and indeed of 

 their lower division, so that I have not the least hesitation about 

 placing the English beds with Bhynchonella inconstans parallel to the 

 Hanoverian Lower Kimmeridge. The characteristic shell of this 

 zone does not indeed occur in the North-German Jurassic deposits, 

 for the species cited by some observers under this name from the 

 Coralline Oolite, especially from Goslar, is erroneously referred to 

 the English species, and is rather a large variety of Bhynchonella 

 pingiiis, A. Rom., or, more probably, a new species. The conditions 

 of strati£cation are quite in accordance with the opinion expressed 

 by me. I therefore regard the Kimmeridge Passage-beds as also 

 the equivalent of the zone of Ammonites tenuilobatus in Svvabia, of 

 the Badener beds of Eastern Switzerland, of the Astartian of Western 

 Switzerland, and of the Sequanien superieur of the Hante Marne, 

 and of Boulogne-sur-Mer, according to P. de Loriol. This assump- 

 tion is further borne out by the reciprocal palseontological relations 

 of the immediately following Kimmeridge beds. 



6. The Lower Kimmeridge Clay possesses 25 species of fossil 

 remains which also occur in the Hanoverian Upper Jura, namely, 16 

 Bivalves, 3 Gasteropods, 2 Cephalopods, and 4 Fishes. Of these 

 there have been observed near Hanover : — 



