OF I HE SAT IS S J TEA AXD EXGLAXD. 



265 



16 species which, have been 

 England : — 



Ammonites gigas, Ziet. 



Gravesianus, d'Orb. 



Irius, d'Orb. 



!Natica Marcousana, D'Orb. 



elegans, De Lor. 



*Pleuroinya tellina, Ag. 

 Plectomya rugosa, Bom. 

 Cardiuin dissiinile, Soiv. 



* Also ranges do 



met with in the Portlanclian of 



Cyprina Brongniarti, Pict. 

 Lucina portlaudica, Sow. 

 Trigonia concentrica, Ag. 



gibbosa, Ag. 



Mytilus boloniensis, De Lor. 

 Pinna suprajurensis, D'Orb. 

 Pecten suprajurensis, D'Orb. 

 Perna Bouchardi, Opp. 



to the Corallian. 



The three first-named fossils in the list are quoted by Judd from 

 the Portlandian of Speeton (Q. J. Gr. S. vol. xxiv. p. 238), and the 

 others are found in Blake's list of fossils from the Portland Rocks 

 of England (Q. J. G. S. vol. xxxvi. p. 235). The above list clearly 

 shows that the fauna of the Portlandian of the Jura is closely allied to 

 that of the Portland rocks of England, and this is more especially the 

 case with the Portland beds of Speeton, as stated by Prof. Judd (op. 

 cit. p. 238). Neither in Greppin's nor in Jaccard's list of Portlandian 

 fossils is there a single species characteristic of the Upper Kimeridge 

 Clay of England, although it is highly probable that these beds are 

 partly the representatives of the Portlandian. We have seen that 

 the beds which underlie the Portlandian, namely, the Tirgulian, are 

 probably represented by the upper portion of the Lower Kimeridge 

 Clay. If such be the case, then the Upper Kimeridge must repre- 

 sent, in time at least, a part of the Portlandian of the Jura. Blake 

 correlates the Portlandian of the Paris Basin with the Upper 

 Kimeridge and Portland beds of England. Waagen and Eenevier 

 do the same for the Portlandian of the Jura, a view which, from 

 palseontological and stratigraphical considerations, appears to be 

 correct. 



The Purbeckian of the Jura has, as already stated, been fully 

 described by Jaccard and De Loriol (Soc. Phys. et d'Histoire Xat. de 

 Geneve, vol. xiii.) and also by "Maillard (Mem. Soc. Pal. Suisse, 

 vols. xi. & xii.). From palseontological considerations, Jaccard and 

 De Loriol regard the Purbeckian of the Jura as the equivalent of the 

 Purbeck beds of England, of which it represents the Middle and 

 Lower divisions (op. cit. p. 64). Maillard arrives at exactly the 

 same conclusion (op. cit. vol. xi. p. 133). He states that 16 of the 

 Purbeckian fossils occur in England in the following beds : — 



Three are exclusively Wealden : — 



Lioplax inflata, Sandb. 

 Psammobia tellinoides, Sow. 



Unio subtruncatus, Sow. 



Three species are found in the Wealden and Purbeck : — 



Corbula alata, Sow. 

 Cyrena angulata, Sandb. 



Q. J. as. No. 170. 



Cyrena media, Sow. 



