)10 A. J. Jukes-Broioie — I'tco Stages, in Upper Chalk. 



From this table it will be seeu that in Germanj' there are two very 

 distinct af5semblao;es of Cephalopoda; the one set being almost entirely 

 restricted to the four lower zones, and the other set to the qtiadratus 

 and mucronata zones. The one fauna comprises forty-seven species 

 and the other forty-six species, of which only two are common to 

 b(jth, these two being Desmoceras ohscurum and Scaphites hippocrepis. 

 All the commoner and characteristic species of eacli fauna are absolutely 

 restricted to it. 



The passage zone of S. bhiodo.ius has yielded fifteen species, of which 

 eight are peculiar to it, two range up into the quadratus zone, and five 

 range down into lower zones. It will be seen in the sequel that the 

 evidence of the Inocerami confirms the inference tluit this zone is more 

 closely allied to the zone below than to the one above. Hence 

 Dr. Scbliiter seems to have been fully justified in drawing the line 

 between his Uuter- and Ober-Senon at the base of the quadratus cluilk. 



We will now pass to Belgium and the North of France, where a 

 fair number of Cephalopoda have been obtained, though far fewer 

 than in German3\ The following table shows the range of those 

 which have been recorded from Belgium, the Cotentin, and Touraine, 

 as well as from tlie Paris Basin proper ; but it will be seen that few 

 species are yet known to occur in the zones of A. granulatus and 

 A. quadratus. In the Paris Basin these zones have not yet been 

 specially examined and searched, except in the neighbourhood of 

 Sens and of Reims ; a few remains of Ammonoids have been found 



