172 MESSES. A. J. JUKES-BROWNE AND W. HILL : [May 1896, 



ourselves as without doubt the base of the 'Cenomanien' is sufficient 

 to prove that this base is a clearly-marked horizon. Now it seemed 

 to us equally clear that this basement-bed corresponded to the 

 Chloritie Marl of the Isle of Wight, or zone of Stauronema Carteri. 

 The overlying beds are therefore the equivalent of our Chalk Marl, 

 and the material of them is a chalky marl, though more visibly 

 glauconitic than our Chalk Marl. At a certain level there is a bed 

 which has some resemblance to Totternhoe Stone, and above this 

 Holaster subglobosus becomes common, just as it does in some parts 

 of England. About 80 feet from the base is a band of glauconitic 

 chalk with phosphate-nodules, but there is no marked change of 

 fauna here, and between 30 and 40 feet above this band we reach 

 the base of the Turonian. 



In our opinion, therefore, the acknowledged ' Cenomanien ' of 

 these cliffs is the equivalent of our Lower Chalk, and of that only. 

 That its fauna should contain a certain admixture of species which 

 lived in English waters at the very close of the Upper Greensand 

 epoch can only surprise those who imagine that every portion of a 

 contemporaneous set of beds must hold precisely the same fauna, 

 whether one portion was formed in shallower water or not. The 

 presence of Pecten asper and other fossils which do not occur in our 

 Chalk Marl is capable of a very simple explanation, which we shall 

 mention further on. 



Beneath this ' Cenomanien ' at Cape La Heve there is a represen- 

 tative of our Gault-and-Upper Greensand group. It is of no great 

 thickness, only about 35 feet, unless the basal conglomerate or 

 Carstone be added, as M. Lennier thinks it should, which would 

 raise the total to 50 feet In this thickness, however, the Lower 

 Gault (or Albien proper), together with so much of the Upper 

 Greensand as is included in the zone of Ammonites rostratus (or 

 Gaize), are clearly represented, but we do not think that any equiva- 

 lent of the English zone of Pecten asper is present. This zone is so 

 variable a quantity in England that there is nothing surprising in 

 its being absent at Havre, where the whole Gault-and-Greensand 

 group is evidently in process of thinning out. 



We have seen that on the south coast of England the zone of 

 Pecten asper varies from 60 to about 6 feet, and north of Devizes, 

 in Wiltshire, it thins rapidly till we get a sequence very like that 

 near Havre, namely Chloritie Marl with phosphates resting on a 

 few feet of unfossiliferous marly greensand which passes down into 

 micaceous sandstone or Gaize. Moreover this zone is absent at 

 Eastbourne, Folkestone, and Wissant, and also in Argonne and 

 Perthois on the borders of the Marne and Meuse in the East of 

 Prance, the Chloritie Marl in all these places resting directly on 

 beds which are referred to the zone of Ammonites rostratus. 1 



Passing now to the Cenomanian of the Calvados and Orne, a 

 section near Honfleur seems to show the Chloritie Marl with a some- 

 what different facies, for it no longer contains phosphatic nodules, 



1 See Barrois, 'Terr. Cret. des Ardennes,' Ann. Soc. geol. Nord, vol. v. 

 (1878) p. 332. 



