LOWER CHALK—NORTH-WEST OF FRANCE. 251 
This coast section near Havre has been studied by many French 
geologists, and notably by Messrs. Hebert and Lennier, but these 
two observers differed as to the horizon which should be regarded 
as the base of the Cenomanian, and until 1896 the views which 
prevailed in France with respect to the correlation of the beds seen 
near Havre with the Gault Greensand, and Lower Chalk of Eng¬ 
land were both indefinite and erroneous. 
To Mr. W. Hill belongs the credit of ascertaining and proving 
how much of the so-called Cenomanian of Normandy is really the 
equivalent of our Lower Chalk. He visited it and other French 
localities on several occasions during 1895, and his observations 
were published in a joint paper with myself on “ A Delimitation 
of the Cenomanian.”* Mr. Hill satisfied himself that the bed 
which M. Lennier had regarded as the true base of the Cenoma¬ 
nian was the equivalent of the Chloritic Marl or zone of Stauro- 
nema Garteri of the Isle of Wight. 
This bed (No. 1 in the tabular view, Fig. 54) is separated from 
the marly sand below by a well-marked plane of division, and lias 
at its base a thin seam of brownish sand. The bed itself consists 
of grey marl, full of large dark green glauconite grains, and con¬ 
tains many black phosphatic nodules and many fossils, among 
which Bryozoa and Sponges are abundant. Stauronema Garteri 
is common, and Am. [ Acanth .] Mantelli, Am. [Acanth.] navicularis 
and Am. [Schloenb.] varians make their first appearance in this 
bed. At and near Cap la Heve there are indeed two beds of 
similar character at this horizon with a combined thickness of 6 
feet, but as they are followed eastward to St. Jouin, where they 
come down to the beach, they become condensed into one bed 31- 
feet thick. At St. Jouin the full thickness of this Cenomanian 
group comes into the cliff, and the section there seen is repre¬ 
sented in Fig. 54. 
The beds numbered 2 to 7 represent the lower part of our 
Chalk Marl, but differ in containing much more siliceous matter, 
partly in the form of fine quartz-sand, partly in the abundance 
of sponge-spicules, and partly as disseminated globular colloid 
silica. They contain also frequent layers of chert-nodules. 
The hard grey bed, which is numbered 8 in the accompanying 
section much resembles the Totternhoe Stone of Norfolk and Suf¬ 
folk. It has clearly been formed under similar conditions, but does 
not form a zonal limit, for most of the fossils which occur below 
range into the beds above. 
Quart. Journ. Geol. Sue., Vol. lii. p. 99 
