250 THE CRETACEOUS ROCKS OF BRITAIN 
CHAPTER XXL 
THE LOWER CHALK (CENOMANIAN) IN THE 
NORTH-WEST OF FRANCE. 
General Remarks. 
On the western side of the Pails basin the Cenomanian beds, 
which include the representative of our Lower Chalk crop out in 
the Departments of the Seine Inferieure, Eure, Eure et Loir, Cal 
vados, Orne, and Sarthe. 
In the eastern part of this district the beds consist mainly of 
chalky marls, more or less glauconitic, but comparable to those 
of the English Lower Chalk, and these are well exposed near Rouen 
and Pavilly. When traced toward the west, however, the beds 
become more glauconitic and more sandy, the sandiness increasing 
toward the south-west till in the Sarthe there is neither marl nor 
chalk, but a series of sands and calcareous sandstones. 
With regard to thickness the beds comparable with our Lower 
Chalk are believed to be from 150 to 160 feet thick in the eastern 
part of the Seine Inferieure, but thin gradually westward along 
the coast till they are not more than 60 or 70 feet thick in Calvados. 
Toward the south-west, however, the beds thicken as the arena¬ 
ceous facies comes on, and expand in the Sarthe to a thickness of 
about 300 feet. 
In the following pages we shall give a brief account of the coast 
section near Havre, and of the exposures near Rouen, Vimontiers 
(Orne) and Theligny (Sarthe). For more detailed accounts the 
reader is referred to a paper by Mr. Hill and myself (Quart. Journ. 
Geol. Soc. Vol. lii. p. 99), to papers by M. Bizet in the Bull. Soc. 
Geol. Norm., Vols. viii. and xi., and to the volume by M. Guillier 
on the Geology of the Sarthe (1886). 
Stratigraphical Details. 
Seine Inferieure .—The cliffs of Normandy east of Cap la Hew 
present a fine section of the Cenomanian, which here exhibits a 
special facies, partly sandy and siliceous and partly chalky, so that 
it forms a connecting link between the purely chalky fao'es of the 
Isle of Wight and the arenaceous deposits of the Orne and Sarthe. 
