550 Dr. C. Siruchinann — The Jura of Hanover and England. 



h. Of the 68 species of the Middle Calcareous Grit, etc., tLere 

 are, near Hanover : — 



Peculiar to the Lower Coralliue Oolite 55 species. 



Only occurring lower 6 ,, 



Only higher (including 2 species in the Upper Coralline Oolite) 7 ,, 



Only 25 species are peculiar to the Tipper Coralline Oolite, so 

 that the palasontological affinity to the Lower Coralline Oolite is 

 considerably greater. Of the above 55 species, the following 11 

 species are, so far as at present known, limited to the Lower 

 Coralline Oolite, namely : — MontUvaltia suhdispar/^ Thamnastrcea 

 arachnoides/'' IsastrcBu explanata/'' Millericrinns ecJiinatus, Pseudo- 

 diadema liemisplioericvm,^^ Qhjpticus hieroglypMcus/-^ Pygaster um- 

 brella/^ Pecten incequicostatus/-^ Lima densepunctata,^-' Opis Phillips- 

 iana, and Isodonta Deshayesea.^'-' 



The species marked with an asterisk are confined in England also 

 to this division according to the evidence before me. 



Hence it cannot be at all doubtful that we must seek the parallels 

 for this middle division of the " Corallian Eocks " in the North 

 German Coralline Oolite, and indeed especially in the Lower 

 Coralline Oolite {Crenidaris-heds of the Aargau according to 

 Moesch, " Rauracien inferieur" of Tribolet, " Sequanien inferieur " 

 of the Haute-Marne of P. de Loriol, beds with Ammonites himammatus 

 (inferior zone) or beds with Cidaris florigemma (inferior zone) of 

 Oppel). The agreement in the stratigraphical and palseontological 

 conditions may be characterized as complete. 



4. The Supracoralline heds (Upper Calcareous Grit) in England 

 show 30 species which also occur in the Hanoverian Upper Jura, 

 and among them ai-e 4 Echinoids, 16 Conchifera, and 6 Gasteropods. 



a. Of the SO sj)ecies there belong 



To the Hanoverian Coralline Oolite in general 22 species. 



Only to lower beds {Fholadomya hemicardia) 1 , , 



Only to higher heds, e.e. the Kimmeridge 7 ,, 



These last species are : — Terehratula subsella, Area superba, Nuctda 

 Menkei, Astarte supracorallina, Pleuromya tellina, Corbula Deshayesea 

 and Natica Eudora. 



b. On the other hand, there are of the 30 common species 



In the Hanoverian Kimmeridge in general 12 species. 



Only in lower beds 18 ,, 



Of the last-mentioned 18 species, eight, according to extant observa- 

 tions, belong exclusively to the Coralline Oolite, namely: — Cidaris 

 Jlorigemma, Hemicidaris intermedia, Pygurus pentngonalis/'' Ostrea 

 deltoidea, Goniomya mMrginala, Trochus exigiius/'' Chemnitzia pseudo- 

 limbata and Natica Clio.^' Of these the three species marked with 

 an asterisk are peculiar to the Upper Coralline Oolite, and the other 

 five species to the Lower Coralline Oolite ; ten species also occur in 

 the Hersumer beds, among which are Pecten vimineus, Lima rigida, 

 Ammonites plicatilis, and Colly rites bicordatus, species which, with us, 

 are characteristic of a lower horizon. 



c. Of the 12 species which are found in the North-Germau 



