Reviews — A. de Grossouvre on the Upper Chalk. 41 



one relies entirely on the succession of Ammonite faunas, putting all 

 other fossils aside, the gaize of Havre and that of Argonne will 

 necessarily be excluded from the Cenomanien." 



With regard to the upper limit of the stage, he says that it is 

 almost everywhere clearly indicated by the disappearance of the roto- 

 magensis group of the genus Acanthoceras and their i-eplacement by 

 the ornatissimum group, as well as by the appearance of Fachydiscus 

 peramplus (which he refers to the genus Neoptijchites) . By this 

 criterion he places the subzone oi Actinocamax plenus in the Turonian, 

 because M. Lambert has found Pach. peramplus in it at Dracy 

 (Yonne), but in England Acanth. rotomagensis has been found in it 

 and Pach. peramplus has not, so that by the same criterion we do 

 right to retain the Belemnite marl in the Lower Chalk (Cenomanian). 



For the Turonian he accepts D'Orbigny's definition of that stage in 

 Touraine as including all the beds between the Cenomanian and the 

 ' craie de Villedieu.' As the base of the latter appears to lie some- 

 where in what is usually called the zone of Micraster cortestudinarium, 

 it is evident that, according to D'Orbigny and De Grossouvre, the 

 Turonian should comprise the beds which have hitherto been known 

 in France as the zones oi Inoceramus labiatus, of TerebratuUna gracilis, 

 and of JPolaster planus, with a portion of the zone of Micraster 

 cortestudinarium. M. de Grossouvre, however, takes the Ammonoidea 

 as his zonal guides, and divides his Turonian into four zones, which 

 are grouped under two sub-stages thus : — 



I. . ( zone of Acanthoceras Beverim. 



Angoumien \ a ,i ,- • 



° ,, Acanthoceras ornatissimum. 



rj • i ,, Acanthoceras Bizeti. 



baumurien < „, .. , ., 



( ,, Mammites nodosoides. 



In the Senonian M. de Grossouvre groups ail the higher Cretaceous 

 beds which are found in France, and he divides the stage into two 

 large sub-stages for which he adopts the names Corhierien and 

 Campanien, the former corresponding mainly with the zones of 

 Micraster coranguinum and Marsupites, the latter with the zones 

 of Actinocamax quadratus and Belemnitella mucronata. He regards 

 the Maestrichtien of Belgium as only a facies of the craie de Meudon, 

 and the Dordonien of Aquitaine as another facies of about the same 

 age, so that both these divisions are brought within the limits of 

 his Campanien. 



Finally, he excludes the ' calcaire pisolitique ' of France and the 

 limestones of Saltholm and of Faxe from the Cretaceous system, on 

 the ground that they contain no Ammonites. He places them, with the 

 Montien of Belgium, as the basal portion of the Tertiary succession, 

 though he hesitates to call them Eocene. In this he follows the 

 Geological Survey of Belgium, who have created a ' Pal^ocene 

 System ' for their Montien, but it is generally admitted that the 

 typical Danien is older than the Montien, and for myself I fail to 

 see that the absence of Ammonites is a sufficient reason for excluding 

 the Saltholm and Faxe beds from the Cretaceous system. 



Returning to M. de Grossouvre's classification of the Senonian, 

 there can be no doubt that he avoids some difficulties by taking 



