368 A. J. Jukea-Bruinic — Tico Stat/es in Upj^er Chalk. 

 TABLE IX. 



IiVOCERAMr IN THE UPPER CHAIiK OF THE PAEIS BASIN. 



Species. 





Inoceramus Lainarcki, Park, (type) . 

 I. LamaixM, var. Cuvieri, Sow. . 

 I. Laniarcki, var. Mantelli, de Mercey 

 I. Lamarcki, var. undulatus, Sow. . 

 I. inconstans, Woods ( = Brongniarti) . 



I. involutus, Sow 



I. digitatus, Sow 



I. lezennensis, Decocq 



I. mceqttivalvis, Schliiter .... 



J. zmduloplicatus, Rom 



I. subcardissoides, Schliiter .... 

 I. halticus (=Crippsi, auct.) . . . 

 I. lingua, Goldf 



Prom these lists it will be seen that the English, list is the most 

 complete, and that the evidence of the Inocerami accoi'ds entirely 

 with that of the Cephalopoda. The zone of Ojfaster pilula in England 

 has yielded nine species, of which live, and probably six, range 

 downward, while only three of them range upward. In Germany 

 the same zone has yielded four species, all of which range down into 

 the Marsupites zone and only one (halticus) passes up into the 

 higher zones. 



Infekences. 



Reviewing the results which have been obtained from the tabulated 

 distribution of Cephalopoda, Echinoderms, and Inocerami in the 

 Upper Chalk, we arrive at the following conclusions : — 



1. That the Upper Chalk, with its equivalent in Erance and 

 Germany, contains two distinct assemblages or faunas, and con- 

 sequently that it comprises two stages as distinct from one another 

 as are the Albian, Cenomanian, and Turonian. 



2. That the evidence of the Cephalopoda fixes the line of division 

 between the zones of Offaster pilula and Actinocamax quadratus. 



3. That the distribution of Inocerami in all three countries leads 

 to the same conclusion as that of the Cephalopoda. 



4. Tliat the evidence of the Echinoderms is less definite, because 

 the assemblage found in the 0. pihda zone is everywhere a passage 

 fauna with many species that range both up and down. 



The exact position of the boundary-plane between the two stages 

 is of course a mere matter of detail. The important point, which is 

 so obvious from an inspection of the preceding tables, is the recognition 

 of the fact that our Upper Chalk is not a single stage comparable 

 with the Middle Chalk or Turonian, but comprises two such stages 

 for which names must be adopted. 



