Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 115 



which occur in the quartziferous limestones of the coast. It is 

 especially rich in ammonites, and nearly all the species occurring 

 at Chard are found also in our coast-zone of Ammonites Maatelli, as 

 will be seen from the list given on p. 159. 



The relative thickness of the beds in the principal sections above 

 described is shown in the accompanying ' Tabular View.' 



III. A Study op the Cliffs between Cape La Heve and Bbunval. 



The bold and almost unbroken line of cliffs which form the 

 French coast from Cape d'Antifer to Cape La Heve present a section 

 of the Cretaceous series from the higher zones of the Upper Chalk 

 seen at the first-named promontory to the yellow sands which 

 form the basement-bed, and which can be seen overlying the 

 Jurassic rocks at Cape La Heve. 



The general trend of these cliffs is about N.N.E. and S.S.W., 

 but at the mouth of the Seine, after passing the lighthouses at 

 Cape La Heve, the cliff turns to the south, making an obtuse angle 

 to the general coast-line. 



Between Cape La Heve and St. Jouin, a distance of some 11 

 miles, the strata are nearly horizontal, and the series seen are the 

 beds from the base of the Cretaceous series to an horizon equivalent 

 to our Grey Chalk ; but at St. Jouin the beds dip gradually to the 

 eastward, and the whole series is brought down to sea-level. 



The section has been well studied by many French geologists, 

 notably by MM. Lesueur, 1 le Vicomte d'Archiac, 2 Hebert, 3 de 

 Lapparent, 4 and Lennier, 5 but even their descriptions do not 

 furnish a complete account of the whole section, nor do they give 

 full lists of the fossils found in the various beds. 



Moreover, since De la Beche's visit in 1821, 6 and Mr. Pratt's 7 

 notice in 1837, no English geologist seems to have studied this fine 

 section. Those who have described English Cretaceous fossils seem 

 to have taken it for granted that the Cenomanian of Normandy 

 included representatives of both our Upper Greensand and Lower 

 Chalk ; but, so far as we can ascertain, no one has hitherto attempted 

 to ascertain how much of this Cenomanian would be regarded as 

 the equivalent of the Lower Chalk. This has been our endeavour, 

 but before entering into details we give the general succession of 

 the series below the Turonian, as seen in the cliffs. This is as 

 follows in descending order, the grouping being that of M. Lennier 

 and Prof, de Lapparent : — 



1 ' Yues et Coupes des Environs du Havre,' Paris, 1843. 



2 ' Etudes sur la Formation Cretacee,' Mem. Soe. Geol. France, ser. 2, vol. ii. 

 p. 95. 



3 Bull. Soc. Geol. France, ser. 2, vol. xxix. (1872), p. 446 ; ibid. ser. 3, 

 vol. iii. (1875) p. 512. 



4 ' Traite de Geologic' 2nd ed. 1885, p. 1074. 



5 Bull. Soc. Geol. Normandie, vol. vi. p. 380, and vol. ix. p. 56 (1880 & 1884). 



6 Trans. Geol. Soc. ser. 2, vol. i. pt. i. (1822) p. 73. 



7 Proc. Geol. Soc. vol. ii. p. 546. 



Q. J. G. S. No. 206. k 



